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[PATCH v24 3/5] Make archiver process an auxiliary process
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* [PATCH v24 3/5] Make archiver process an auxiliary process
@ 2018-11-07 07:53  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2018-11-07 07:53 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.
Archiver process must be a auxiliary process since it uses shared
memory after stats data wes moved onto shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/bootstrap/bootstrap.c   |  8 +++
 src/backend/postmaster/pgarch.c     | 98 +++++++----------------------
 src/backend/postmaster/pgstat.c     |  6 ++
 src/backend/postmaster/postmaster.c | 35 ++++++++---
 src/include/miscadmin.h             |  2 +
 src/include/pgstat.h                |  1 +
 src/include/postmaster/pgarch.h     |  4 +-
 7 files changed, 67 insertions(+), 87 deletions(-)

diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 8ea033610d..6e38f9a3d2 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -329,6 +329,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			case BgWriterProcess:
 				statmsg = pgstat_get_backend_desc(B_BG_WRITER);
 				break;
+			case ArchiverProcess:
+				statmsg = pgstat_get_backend_desc(B_ARCHIVER);
+				break;
 			case CheckpointerProcess:
 				statmsg = pgstat_get_backend_desc(B_CHECKPOINTER);
 				break;
@@ -456,6 +459,11 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			BackgroundWriterMain();
 			proc_exit(1);		/* should never return */
 
+		case ArchiverProcess:
+			/* don't set signals, archiver has its own agenda */
+			PgArchiverMain();
+			proc_exit(1);		/* should never return */
+
 		case CheckpointerProcess:
 			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index f84f882c4c..4342ebdab4 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -77,7 +77,6 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
@@ -96,7 +95,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
 static void pgarch_exit(SIGNAL_ARGS);
 static void ArchSigHupHandler(SIGNAL_ARGS);
 static void ArchSigTermHandler(SIGNAL_ARGS);
@@ -114,75 +112,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -222,8 +151,8 @@ pgarch_forkexec(void)
  *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
  *	since we don't use 'em, it hardly matters...
  */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -255,8 +184,27 @@ PgArchiverMain(int argc, char *argv[])
 static void
 pgarch_exit(SIGNAL_ARGS)
 {
-	/* SIGQUIT means curl up and die ... */
-	exit(1);
+	PG_SETMASK(&BlockSig);
+
+	/*
+	 * We DO NOT want to run proc_exit() callbacks -- we're here because
+	 * shared memory may be corrupted, so we don't want to try to clean up our
+	 * transaction.  Just nail the windows shut and get out of town.  Now that
+	 * there's an atexit callback to prevent third-party code from breaking
+	 * things by calling exit() directly, we have to reset the callbacks
+	 * explicitly to make this work as intended.
+	 */
+	on_exit_reset();
+
+	/*
+	 * Note we do exit(2) not exit(0).  This is to force the postmaster into a
+	 * system reset cycle if some idiot DBA sends a manual SIGQUIT to a random
+	 * backend.  This is necessary precisely because we don't clean up our
+	 * shared memory state.  (The "dead man switch" mechanism in pmsignal.c
+	 * should ensure the postmaster sees this as a crash, too, but no harm in
+	 * being doubly sure.)
+	 */
+	exit(2);
 }
 
 /* SIGHUP signal handler for archiver process */
diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c
index fabcf31de8..8299d2a435 100644
--- a/src/backend/postmaster/pgstat.c
+++ b/src/backend/postmaster/pgstat.c
@@ -2932,6 +2932,9 @@ pgstat_bestart(void)
 			case StartupProcess:
 				lbeentry.st_backendType = B_STARTUP;
 				break;
+			case ArchiverProcess:
+				beentry->st_backendType = B_ARCHIVER;
+				break;
 			case BgWriterProcess:
 				lbeentry.st_backendType = B_BG_WRITER;
 				break;
@@ -4275,6 +4278,9 @@ pgstat_get_backend_desc(BackendType backendType)
 
 	switch (backendType)
 	{
+		case B_ARCHIVER:
+			backendDesc = "archiver";
+			break;
 		case B_AUTOVAC_LAUNCHER:
 			backendDesc = "autovacuum launcher";
 			break;
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 9ff2832c00..84fda38249 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -146,7 +146,8 @@
 #define BACKEND_TYPE_AUTOVAC	0x0002	/* autovacuum worker process */
 #define BACKEND_TYPE_WALSND		0x0004	/* walsender process */
 #define BACKEND_TYPE_BGWORKER	0x0008	/* bgworker process */
-#define BACKEND_TYPE_ALL		0x000F	/* OR of all the above */
+#define BACKEND_TYPE_ARCHIVER	0x0010	/* archiver process */
+#define BACKEND_TYPE_ALL		0x001F	/* OR of all the above */
 
 #define BACKEND_TYPE_WORKER		(BACKEND_TYPE_AUTOVAC | BACKEND_TYPE_BGWORKER)
 
@@ -539,6 +540,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1785,7 +1787,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3042,7 +3044,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3187,10 +3189,8 @@ reaper(SIGNAL_ARGS)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3438,7 +3438,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3643,6 +3643,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3915,6 +3927,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5190,7 +5203,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5475,6 +5488,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index bc6e03fbc7..1f4db67f3f 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -399,6 +399,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -411,6 +412,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index fe076d823d..65713abc2b 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -718,6 +718,7 @@ typedef struct PgStat_GlobalStats
  */
 typedef enum BackendType
 {
+	B_ARCHIVER,
 	B_AUTOVAC_LAUNCHER,
 	B_AUTOVAC_WORKER,
 	B_BACKEND,
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index 2474eac26a..88f16863d4 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
-- 
2.23.0


----Next_Part(Tue_Dec__3_17_27_59_2019_887)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
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 filename="v24-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH 3/5] Make archiver process an auxiliary process
@ 2018-11-07 07:53  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2018-11-07 07:53 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.
Archiver process must be a auxiliary process since it uses shared
memory after stats data wes moved onto shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/bootstrap/bootstrap.c   |  8 +++
 src/backend/postmaster/pgarch.c     | 98 +++++++----------------------
 src/backend/postmaster/pgstat.c     |  6 ++
 src/backend/postmaster/postmaster.c | 43 ++++++++-----
 src/include/miscadmin.h             |  2 +
 src/include/pgstat.h                |  1 +
 src/include/postmaster/pgarch.h     |  4 +-
 7 files changed, 70 insertions(+), 92 deletions(-)

diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index bfc629c753..2f38420313 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -326,6 +326,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			case StartupProcess:
 				statmsg = pgstat_get_backend_desc(B_STARTUP);
 				break;
+			case ArchiverProcess:
+				statmsg = pgstat_get_backend_desc(B_ARCHIVER);
+				break;
 			case BgWriterProcess:
 				statmsg = pgstat_get_backend_desc(B_BG_WRITER);
 				break;
@@ -451,6 +454,11 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			StartupProcessMain();
 			proc_exit(1);		/* should never return */
 
+		case ArchiverProcess:
+			/* don't set signals, archiver has its own agenda */
+			PgArchiverMain();
+			proc_exit(1);		/* should never return */
+
 		case BgWriterProcess:
 			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index 3ca30badb2..6441e69e9a 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -78,7 +78,6 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
@@ -95,7 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
 static void pgarch_exit(SIGNAL_ARGS);
 static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
@@ -111,75 +109,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -219,8 +148,8 @@ pgarch_forkexec(void)
  *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
  *	since we don't use 'em, it hardly matters...
  */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -252,8 +181,27 @@ PgArchiverMain(int argc, char *argv[])
 static void
 pgarch_exit(SIGNAL_ARGS)
 {
-	/* SIGQUIT means curl up and die ... */
-	exit(1);
+	PG_SETMASK(&BlockSig);
+
+	/*
+	 * We DO NOT want to run proc_exit() callbacks -- we're here because
+	 * shared memory may be corrupted, so we don't want to try to clean up our
+	 * transaction.  Just nail the windows shut and get out of town.  Now that
+	 * there's an atexit callback to prevent third-party code from breaking
+	 * things by calling exit() directly, we have to reset the callbacks
+	 * explicitly to make this work as intended.
+	 */
+	on_exit_reset();
+
+	/*
+	 * Note we do exit(2) not exit(0).  This is to force the postmaster into a
+	 * system reset cycle if some idiot DBA sends a manual SIGQUIT to a random
+	 * process.  This is necessary precisely because we don't clean up our
+	 * shared memory state.  (The "dead man switch" mechanism in pmsignal.c
+	 * should ensure the postmaster sees this as a crash, too, but no harm in
+	 * being doubly sure.)
+	 */
+	exit(2);
 }
 
 /* SIGUSR1 signal handler for archiver process */
diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c
index 51c486bebd..ca5c6376e5 100644
--- a/src/backend/postmaster/pgstat.c
+++ b/src/backend/postmaster/pgstat.c
@@ -2927,6 +2927,9 @@ pgstat_bestart(void)
 			case StartupProcess:
 				lbeentry.st_backendType = B_STARTUP;
 				break;
+			case ArchiverProcess:
+				beentry->st_backendType = B_ARCHIVER;
+				break;
 			case BgWriterProcess:
 				lbeentry.st_backendType = B_BG_WRITER;
 				break;
@@ -4273,6 +4276,9 @@ pgstat_get_backend_desc(BackendType backendType)
 
 	switch (backendType)
 	{
+		case B_ARCHIVER:
+			backendDesc = "archiver";
+			break;
 		case B_AUTOVAC_LAUNCHER:
 			backendDesc = "autovacuum launcher";
 			break;
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7a92dac525..ee41d7009e 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -146,7 +146,8 @@
 #define BACKEND_TYPE_AUTOVAC	0x0002	/* autovacuum worker process */
 #define BACKEND_TYPE_WALSND		0x0004	/* walsender process */
 #define BACKEND_TYPE_BGWORKER	0x0008	/* bgworker process */
-#define BACKEND_TYPE_ALL		0x000F	/* OR of all the above */
+#define BACKEND_TYPE_ARCHIVER	0x0010	/* archiver process */
+#define BACKEND_TYPE_ALL		0x001F	/* OR of all the above */
 
 #define BACKEND_TYPE_WORKER		(BACKEND_TYPE_AUTOVAC | BACKEND_TYPE_BGWORKER)
 
@@ -539,6 +540,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1785,7 +1787,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3042,7 +3044,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3177,20 +3179,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3438,7 +3436,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3643,6 +3641,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3915,6 +3925,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5190,7 +5201,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5475,6 +5486,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 62d64aa0a1..dc7dd1c164 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -397,6 +397,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -409,6 +410,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 36b530bc27..0334213b98 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -718,6 +718,7 @@ typedef struct PgStat_GlobalStats
  */
 typedef enum BackendType
 {
+	B_ARCHIVER,
 	B_AUTOVAC_LAUNCHER,
 	B_AUTOVAC_WORKER,
 	B_BACKEND,
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index b3200874ca..e3ffc63f14 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
-- 
2.23.0


----Next_Part(Wed_Jan_22_17_24_04_2020_620)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v46 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index c87ffc6549..a1e51c5b99 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 0786fcf103..430d438303 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -354,6 +354,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Thu_Jan_14_15_14_25_2021_903)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v46-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v45 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index db0cfaa360..aabf9d73eb 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 0786fcf103..430d438303 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -354,6 +354,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Fri_Jan__8_10_24_34_2021_185)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v45-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v46 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index c87ffc6549..a1e51c5b99 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 0786fcf103..430d438303 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -354,6 +354,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Thu_Jan_14_15_14_25_2021_903)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v46-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v47 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index c87ffc6549..a1e51c5b99 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 683ab64f76..6cdaf3753d 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -355,6 +355,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Thu_Jan_21_12_03_48_2021_284)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v47-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v48 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..22e1cd244c 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3143,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3403,7 +3400,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,6 +3606,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3912,6 +3921,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5140,7 +5150,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5204,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5445,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..491747c113 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Fri_Mar__5_17_18_56_2021_497)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v48-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v49 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 174 +++--------------------
 src/backend/postmaster/postmaster.c      |  88 ++++++------
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 83 insertions(+), 232 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..e237cedaff 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,25 +79,17 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -105,121 +98,9 @@ static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +112,24 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..d9f8d82650 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3126,6 +3127,18 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  We treat it the same way to WAL receiver.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			continue;
+		}
+
 		/*
 		 * Was it the autovacuum launcher?	Normal exit can be ignored; we'll
 		 * start a new one at the next iteration of the postmaster's main
@@ -3141,24 +3154,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3403,7 +3398,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3604,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3904,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -4989,6 +4982,19 @@ SubPostmasterMain(int argc, char *argv[])
 
 		AuxiliaryProcessMain(argc - 2, argv + 2);	/* does not return */
 	}
+	if (strcmp(argv[1], "--forkarch") == 0)
+	{
+		/* Restore basic shared memory pointers */
+		InitShmemAccess(UsedShmemSegAddr);
+
+		/* Need a PGPROC to run CreateSharedMemoryAndSemaphores */
+		InitAuxiliaryProcess();
+
+		/* Attach process to shared data structures */
+		CreateSharedMemoryAndSemaphores();
+
+		PgArchiverMain(); /* does not return */
+	}
 	if (strcmp(argv[1], "--forkavlauncher") == 0)
 	{
 		/* Restore basic shared memory pointers */
@@ -5037,12 +5043,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5140,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5194,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5435,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d73890b228 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,8 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Tue_Mar__9_16_53_11_2021_575)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v49-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v50 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 174 +++--------------------
 src/backend/postmaster/postmaster.c      |  88 ++++++------
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 83 insertions(+), 232 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..e237cedaff 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,25 +79,17 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -105,121 +98,9 @@ static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +112,24 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..d9f8d82650 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3126,6 +3127,18 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  We treat it the same way to WAL receiver.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			continue;
+		}
+
 		/*
 		 * Was it the autovacuum launcher?	Normal exit can be ignored; we'll
 		 * start a new one at the next iteration of the postmaster's main
@@ -3141,24 +3154,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3403,7 +3398,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3604,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3904,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -4989,6 +4982,19 @@ SubPostmasterMain(int argc, char *argv[])
 
 		AuxiliaryProcessMain(argc - 2, argv + 2);	/* does not return */
 	}
+	if (strcmp(argv[1], "--forkarch") == 0)
+	{
+		/* Restore basic shared memory pointers */
+		InitShmemAccess(UsedShmemSegAddr);
+
+		/* Need a PGPROC to run CreateSharedMemoryAndSemaphores */
+		InitAuxiliaryProcess();
+
+		/* Attach process to shared data structures */
+		CreateSharedMemoryAndSemaphores();
+
+		PgArchiverMain(); /* does not return */
+	}
 	if (strcmp(argv[1], "--forkavlauncher") == 0)
 	{
 		/* Restore basic shared memory pointers */
@@ -5037,12 +5043,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5140,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5194,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5435,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d73890b228 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,8 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Tue_Mar__9_18_29_34_2021_806)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v50-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v51 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 194 ++++-------------------
 src/backend/postmaster/postmaster.c      |  83 +++++-----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 94 insertions(+), 236 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..c219780c60 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,13 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,148 +75,29 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +109,27 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +602,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ *  exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	ProcGlobal->archiverLatch = NULL;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..fd509869aa 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3141,24 +3142,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3175,6 +3158,26 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving of remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
+		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			if (PgArchStartupAllowed())
+				PgArchPID = StartArchiver();
+			continue;
+		}
+
 		/* Was it the system logger?  If so, try to start a new one */
 		if (pid == SysLoggerPID)
 		{
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d71700a565 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -350,6 +350,8 @@ typedef struct PROC_HDR
 	Latch	   *walwriterLatch;
 	/* Checkpointer process's latch */
 	Latch	   *checkpointerLatch;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 	/* Current shared estimate of appropriate spins_per_delay value */
 	int			spins_per_delay;
 	/* The proc of the Startup process, since not in ProcArray */
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Wed_Mar_10_12_10_39_2021_432)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v51-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v52 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 224 ++++++++---------------
 src/backend/postmaster/postmaster.c      |  83 ++++-----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  13 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 9 files changed, 139 insertions(+), 222 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..2558bcfb08 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,13 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +493,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..c399e6c267 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,68 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	Latch	*latch;		/* latch to wake the archiver up */
+	slock_t  mutex;		/* locks this struct */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size	size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
+	return size;
+}
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool	found;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver ", PgArchShmemSize(), &found);
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
+	if (!found)
 	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
+		SpinLockInit(&PgArch->mutex);
+		PgArch->latch = NULL;
 	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
 }
-#endif							/* EXEC_BACKEND */
-
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +144,48 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = MyLatch;
+	SpinLockRelease(&PgArch->mutex);
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	Latch	*latch;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
+	SpinLockAcquire(&PgArch->mutex);
+	latch = PgArch->latch;
+	SpinLockRelease(&PgArch->mutex);
 
-	errno = save_errno;
+	if (latch)
+		SetLatch(latch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +210,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +248,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +270,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +656,17 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ *  exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = NULL;
+	SpinLockRelease(&PgArch->mutex);
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..34c8551288 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3141,24 +3142,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3175,6 +3158,26 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
+		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			if (PgArchStartupAllowed())
+				PgArchPID = StartArchiver();
+			continue;
+		}
+
 		/* Was it the system logger?  If so, try to start a new one */
 		if (pid == SysLoggerPID)
 		{
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..d053bf1564 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,9 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Wed_Mar_10_17_51_37_2021_192)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v52-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v45 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index db0cfaa360..aabf9d73eb 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 0786fcf103..430d438303 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -354,6 +354,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Fri_Jan__8_10_24_34_2021_185)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v45-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v46 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index c87ffc6549..a1e51c5b99 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 0786fcf103..430d438303 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -354,6 +354,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Thu_Jan_14_15_14_25_2021_903)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v46-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v47 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index c87ffc6549..a1e51c5b99 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 683ab64f76..6cdaf3753d 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -355,6 +355,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Thu_Jan_21_12_03_48_2021_284)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v47-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v48 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..22e1cd244c 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3143,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3403,7 +3400,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,6 +3606,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3912,6 +3921,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5140,7 +5150,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5204,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5445,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..491747c113 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Fri_Mar__5_17_18_56_2021_497)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v48-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v49 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 174 +++--------------------
 src/backend/postmaster/postmaster.c      |  88 ++++++------
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 83 insertions(+), 232 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..e237cedaff 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,25 +79,17 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -105,121 +98,9 @@ static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +112,24 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..d9f8d82650 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3126,6 +3127,18 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  We treat it the same way to WAL receiver.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			continue;
+		}
+
 		/*
 		 * Was it the autovacuum launcher?	Normal exit can be ignored; we'll
 		 * start a new one at the next iteration of the postmaster's main
@@ -3141,24 +3154,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3403,7 +3398,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3604,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3904,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -4989,6 +4982,19 @@ SubPostmasterMain(int argc, char *argv[])
 
 		AuxiliaryProcessMain(argc - 2, argv + 2);	/* does not return */
 	}
+	if (strcmp(argv[1], "--forkarch") == 0)
+	{
+		/* Restore basic shared memory pointers */
+		InitShmemAccess(UsedShmemSegAddr);
+
+		/* Need a PGPROC to run CreateSharedMemoryAndSemaphores */
+		InitAuxiliaryProcess();
+
+		/* Attach process to shared data structures */
+		CreateSharedMemoryAndSemaphores();
+
+		PgArchiverMain(); /* does not return */
+	}
 	if (strcmp(argv[1], "--forkavlauncher") == 0)
 	{
 		/* Restore basic shared memory pointers */
@@ -5037,12 +5043,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5140,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5194,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5435,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d73890b228 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,8 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Tue_Mar__9_16_53_11_2021_575)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v49-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v50 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 174 +++--------------------
 src/backend/postmaster/postmaster.c      |  88 ++++++------
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 83 insertions(+), 232 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..e237cedaff 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,25 +79,17 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -105,121 +98,9 @@ static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +112,24 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..d9f8d82650 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3126,6 +3127,18 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  We treat it the same way to WAL receiver.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			continue;
+		}
+
 		/*
 		 * Was it the autovacuum launcher?	Normal exit can be ignored; we'll
 		 * start a new one at the next iteration of the postmaster's main
@@ -3141,24 +3154,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3403,7 +3398,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3604,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3904,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -4989,6 +4982,19 @@ SubPostmasterMain(int argc, char *argv[])
 
 		AuxiliaryProcessMain(argc - 2, argv + 2);	/* does not return */
 	}
+	if (strcmp(argv[1], "--forkarch") == 0)
+	{
+		/* Restore basic shared memory pointers */
+		InitShmemAccess(UsedShmemSegAddr);
+
+		/* Need a PGPROC to run CreateSharedMemoryAndSemaphores */
+		InitAuxiliaryProcess();
+
+		/* Attach process to shared data structures */
+		CreateSharedMemoryAndSemaphores();
+
+		PgArchiverMain(); /* does not return */
+	}
 	if (strcmp(argv[1], "--forkavlauncher") == 0)
 	{
 		/* Restore basic shared memory pointers */
@@ -5037,12 +5043,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5140,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5194,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5435,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d73890b228 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,8 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


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 filename="v50-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v51 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 194 ++++-------------------
 src/backend/postmaster/postmaster.c      |  83 +++++-----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 94 insertions(+), 236 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..c219780c60 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,13 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,148 +75,29 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +109,27 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +602,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ *  exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	ProcGlobal->archiverLatch = NULL;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..fd509869aa 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3141,24 +3142,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3175,6 +3158,26 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving of remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
+		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			if (PgArchStartupAllowed())
+				PgArchPID = StartArchiver();
+			continue;
+		}
+
 		/* Was it the system logger?  If so, try to start a new one */
 		if (pid == SysLoggerPID)
 		{
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d71700a565 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -350,6 +350,8 @@ typedef struct PROC_HDR
 	Latch	   *walwriterLatch;
 	/* Checkpointer process's latch */
 	Latch	   *checkpointerLatch;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 	/* Current shared estimate of appropriate spins_per_delay value */
 	int			spins_per_delay;
 	/* The proc of the Startup process, since not in ProcArray */
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


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 filename="v51-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v52 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 224 ++++++++---------------
 src/backend/postmaster/postmaster.c      |  83 ++++-----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  13 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 9 files changed, 139 insertions(+), 222 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..2558bcfb08 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,13 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +493,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..c399e6c267 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,68 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	Latch	*latch;		/* latch to wake the archiver up */
+	slock_t  mutex;		/* locks this struct */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size	size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
+	return size;
+}
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool	found;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver ", PgArchShmemSize(), &found);
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
+	if (!found)
 	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
+		SpinLockInit(&PgArch->mutex);
+		PgArch->latch = NULL;
 	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
 }
-#endif							/* EXEC_BACKEND */
-
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +144,48 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = MyLatch;
+	SpinLockRelease(&PgArch->mutex);
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	Latch	*latch;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
+	SpinLockAcquire(&PgArch->mutex);
+	latch = PgArch->latch;
+	SpinLockRelease(&PgArch->mutex);
 
-	errno = save_errno;
+	if (latch)
+		SetLatch(latch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +210,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +248,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +270,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +656,17 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ *  exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = NULL;
+	SpinLockRelease(&PgArch->mutex);
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..34c8551288 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3141,24 +3142,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3175,6 +3158,26 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
+		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			if (PgArchStartupAllowed())
+				PgArchPID = StartArchiver();
+			continue;
+		}
+
 		/* Was it the system logger?  If so, try to start a new one */
 		if (pid == SysLoggerPID)
 		{
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..d053bf1564 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,9 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Wed_Mar_10_17_51_37_2021_192)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v52-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v45 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index db0cfaa360..aabf9d73eb 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 0786fcf103..430d438303 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -354,6 +354,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Fri_Jan__8_10_24_34_2021_185)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v45-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v46 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index c87ffc6549..a1e51c5b99 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 0786fcf103..430d438303 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -354,6 +354,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Thu_Jan_14_15_14_25_2021_903)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v46-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v47 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index c87ffc6549..a1e51c5b99 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 683ab64f76..6cdaf3753d 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -355,6 +355,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Thu_Jan_21_12_03_48_2021_284)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v47-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v48 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..22e1cd244c 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3143,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3403,7 +3400,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,6 +3606,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3912,6 +3921,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5140,7 +5150,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5204,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5445,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..491747c113 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Fri_Mar__5_17_18_56_2021_497)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v48-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v49 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 174 +++--------------------
 src/backend/postmaster/postmaster.c      |  88 ++++++------
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 83 insertions(+), 232 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..e237cedaff 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,25 +79,17 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -105,121 +98,9 @@ static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +112,24 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..d9f8d82650 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3126,6 +3127,18 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  We treat it the same way to WAL receiver.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			continue;
+		}
+
 		/*
 		 * Was it the autovacuum launcher?	Normal exit can be ignored; we'll
 		 * start a new one at the next iteration of the postmaster's main
@@ -3141,24 +3154,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3403,7 +3398,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3604,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3904,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -4989,6 +4982,19 @@ SubPostmasterMain(int argc, char *argv[])
 
 		AuxiliaryProcessMain(argc - 2, argv + 2);	/* does not return */
 	}
+	if (strcmp(argv[1], "--forkarch") == 0)
+	{
+		/* Restore basic shared memory pointers */
+		InitShmemAccess(UsedShmemSegAddr);
+
+		/* Need a PGPROC to run CreateSharedMemoryAndSemaphores */
+		InitAuxiliaryProcess();
+
+		/* Attach process to shared data structures */
+		CreateSharedMemoryAndSemaphores();
+
+		PgArchiverMain(); /* does not return */
+	}
 	if (strcmp(argv[1], "--forkavlauncher") == 0)
 	{
 		/* Restore basic shared memory pointers */
@@ -5037,12 +5043,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5140,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5194,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5435,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d73890b228 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,8 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Tue_Mar__9_16_53_11_2021_575)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v49-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v50 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 174 +++--------------------
 src/backend/postmaster/postmaster.c      |  88 ++++++------
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 83 insertions(+), 232 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..e237cedaff 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,25 +79,17 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -105,121 +98,9 @@ static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +112,24 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..d9f8d82650 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3126,6 +3127,18 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  We treat it the same way to WAL receiver.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			continue;
+		}
+
 		/*
 		 * Was it the autovacuum launcher?	Normal exit can be ignored; we'll
 		 * start a new one at the next iteration of the postmaster's main
@@ -3141,24 +3154,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3403,7 +3398,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3604,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3904,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -4989,6 +4982,19 @@ SubPostmasterMain(int argc, char *argv[])
 
 		AuxiliaryProcessMain(argc - 2, argv + 2);	/* does not return */
 	}
+	if (strcmp(argv[1], "--forkarch") == 0)
+	{
+		/* Restore basic shared memory pointers */
+		InitShmemAccess(UsedShmemSegAddr);
+
+		/* Need a PGPROC to run CreateSharedMemoryAndSemaphores */
+		InitAuxiliaryProcess();
+
+		/* Attach process to shared data structures */
+		CreateSharedMemoryAndSemaphores();
+
+		PgArchiverMain(); /* does not return */
+	}
 	if (strcmp(argv[1], "--forkavlauncher") == 0)
 	{
 		/* Restore basic shared memory pointers */
@@ -5037,12 +5043,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5140,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5194,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5435,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d73890b228 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,8 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Tue_Mar__9_18_29_34_2021_806)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v50-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v51 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 194 ++++-------------------
 src/backend/postmaster/postmaster.c      |  83 +++++-----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 94 insertions(+), 236 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..c219780c60 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,13 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,148 +75,29 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +109,27 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +602,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ *  exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	ProcGlobal->archiverLatch = NULL;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..fd509869aa 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3141,24 +3142,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3175,6 +3158,26 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving of remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
+		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			if (PgArchStartupAllowed())
+				PgArchPID = StartArchiver();
+			continue;
+		}
+
 		/* Was it the system logger?  If so, try to start a new one */
 		if (pid == SysLoggerPID)
 		{
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d71700a565 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -350,6 +350,8 @@ typedef struct PROC_HDR
 	Latch	   *walwriterLatch;
 	/* Checkpointer process's latch */
 	Latch	   *checkpointerLatch;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 	/* Current shared estimate of appropriate spins_per_delay value */
 	int			spins_per_delay;
 	/* The proc of the Startup process, since not in ProcArray */
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Wed_Mar_10_12_10_39_2021_432)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v51-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v52 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 224 ++++++++---------------
 src/backend/postmaster/postmaster.c      |  83 ++++-----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  13 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 9 files changed, 139 insertions(+), 222 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..2558bcfb08 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,13 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +493,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..c399e6c267 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,68 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	Latch	*latch;		/* latch to wake the archiver up */
+	slock_t  mutex;		/* locks this struct */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size	size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
+	return size;
+}
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool	found;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver ", PgArchShmemSize(), &found);
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
+	if (!found)
 	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
+		SpinLockInit(&PgArch->mutex);
+		PgArch->latch = NULL;
 	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
 }
-#endif							/* EXEC_BACKEND */
-
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +144,48 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = MyLatch;
+	SpinLockRelease(&PgArch->mutex);
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	Latch	*latch;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
+	SpinLockAcquire(&PgArch->mutex);
+	latch = PgArch->latch;
+	SpinLockRelease(&PgArch->mutex);
 
-	errno = save_errno;
+	if (latch)
+		SetLatch(latch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +210,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +248,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +270,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +656,17 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ *  exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = NULL;
+	SpinLockRelease(&PgArch->mutex);
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..34c8551288 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3141,24 +3142,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3175,6 +3158,26 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
+		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			if (PgArchStartupAllowed())
+				PgArchPID = StartArchiver();
+			continue;
+		}
+
 		/* Was it the system logger?  If so, try to start a new one */
 		if (pid == SysLoggerPID)
 		{
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..d053bf1564 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,9 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Wed_Mar_10_17_51_37_2021_192)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v52-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v45 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index db0cfaa360..aabf9d73eb 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 0786fcf103..430d438303 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -354,6 +354,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Fri_Jan__8_10_24_34_2021_185)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v45-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v46 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index c87ffc6549..a1e51c5b99 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 0786fcf103..430d438303 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -354,6 +354,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Thu_Jan_14_15_14_25_2021_903)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v46-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v47 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index c87ffc6549..a1e51c5b99 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 683ab64f76..6cdaf3753d 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -355,6 +355,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Thu_Jan_21_12_03_48_2021_284)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v47-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v48 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..22e1cd244c 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3143,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3403,7 +3400,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,6 +3606,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3912,6 +3921,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5140,7 +5150,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5204,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5445,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..491747c113 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Fri_Mar__5_17_18_56_2021_497)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v48-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v49 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 174 +++--------------------
 src/backend/postmaster/postmaster.c      |  88 ++++++------
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 83 insertions(+), 232 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..e237cedaff 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,25 +79,17 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -105,121 +98,9 @@ static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +112,24 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..d9f8d82650 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3126,6 +3127,18 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  We treat it the same way to WAL receiver.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			continue;
+		}
+
 		/*
 		 * Was it the autovacuum launcher?	Normal exit can be ignored; we'll
 		 * start a new one at the next iteration of the postmaster's main
@@ -3141,24 +3154,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3403,7 +3398,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3604,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3904,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -4989,6 +4982,19 @@ SubPostmasterMain(int argc, char *argv[])
 
 		AuxiliaryProcessMain(argc - 2, argv + 2);	/* does not return */
 	}
+	if (strcmp(argv[1], "--forkarch") == 0)
+	{
+		/* Restore basic shared memory pointers */
+		InitShmemAccess(UsedShmemSegAddr);
+
+		/* Need a PGPROC to run CreateSharedMemoryAndSemaphores */
+		InitAuxiliaryProcess();
+
+		/* Attach process to shared data structures */
+		CreateSharedMemoryAndSemaphores();
+
+		PgArchiverMain(); /* does not return */
+	}
 	if (strcmp(argv[1], "--forkavlauncher") == 0)
 	{
 		/* Restore basic shared memory pointers */
@@ -5037,12 +5043,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5140,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5194,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5435,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d73890b228 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,8 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Tue_Mar__9_16_53_11_2021_575)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v49-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v50 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 174 +++--------------------
 src/backend/postmaster/postmaster.c      |  88 ++++++------
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 83 insertions(+), 232 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..e237cedaff 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,25 +79,17 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -105,121 +98,9 @@ static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +112,24 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..d9f8d82650 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3126,6 +3127,18 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  We treat it the same way to WAL receiver.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			continue;
+		}
+
 		/*
 		 * Was it the autovacuum launcher?	Normal exit can be ignored; we'll
 		 * start a new one at the next iteration of the postmaster's main
@@ -3141,24 +3154,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3403,7 +3398,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3604,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3904,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -4989,6 +4982,19 @@ SubPostmasterMain(int argc, char *argv[])
 
 		AuxiliaryProcessMain(argc - 2, argv + 2);	/* does not return */
 	}
+	if (strcmp(argv[1], "--forkarch") == 0)
+	{
+		/* Restore basic shared memory pointers */
+		InitShmemAccess(UsedShmemSegAddr);
+
+		/* Need a PGPROC to run CreateSharedMemoryAndSemaphores */
+		InitAuxiliaryProcess();
+
+		/* Attach process to shared data structures */
+		CreateSharedMemoryAndSemaphores();
+
+		PgArchiverMain(); /* does not return */
+	}
 	if (strcmp(argv[1], "--forkavlauncher") == 0)
 	{
 		/* Restore basic shared memory pointers */
@@ -5037,12 +5043,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5140,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5194,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5435,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d73890b228 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,8 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Tue_Mar__9_18_29_34_2021_806)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v50-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v51 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 194 ++++-------------------
 src/backend/postmaster/postmaster.c      |  83 +++++-----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 94 insertions(+), 236 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..c219780c60 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,13 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,148 +75,29 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +109,27 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +602,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ *  exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	ProcGlobal->archiverLatch = NULL;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..fd509869aa 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3141,24 +3142,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3175,6 +3158,26 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving of remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
+		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			if (PgArchStartupAllowed())
+				PgArchPID = StartArchiver();
+			continue;
+		}
+
 		/* Was it the system logger?  If so, try to start a new one */
 		if (pid == SysLoggerPID)
 		{
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d71700a565 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -350,6 +350,8 @@ typedef struct PROC_HDR
 	Latch	   *walwriterLatch;
 	/* Checkpointer process's latch */
 	Latch	   *checkpointerLatch;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 	/* Current shared estimate of appropriate spins_per_delay value */
 	int			spins_per_delay;
 	/* The proc of the Startup process, since not in ProcArray */
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


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Content-Transfer-Encoding: 7bit
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 filename="v51-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v52 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 224 ++++++++---------------
 src/backend/postmaster/postmaster.c      |  83 ++++-----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  13 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 9 files changed, 139 insertions(+), 222 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..2558bcfb08 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,13 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +493,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..c399e6c267 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,68 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	Latch	*latch;		/* latch to wake the archiver up */
+	slock_t  mutex;		/* locks this struct */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size	size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
+	return size;
+}
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool	found;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver ", PgArchShmemSize(), &found);
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
+	if (!found)
 	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
+		SpinLockInit(&PgArch->mutex);
+		PgArch->latch = NULL;
 	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
 }
-#endif							/* EXEC_BACKEND */
-
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +144,48 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = MyLatch;
+	SpinLockRelease(&PgArch->mutex);
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	Latch	*latch;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
+	SpinLockAcquire(&PgArch->mutex);
+	latch = PgArch->latch;
+	SpinLockRelease(&PgArch->mutex);
 
-	errno = save_errno;
+	if (latch)
+		SetLatch(latch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +210,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +248,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +270,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +656,17 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ *  exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = NULL;
+	SpinLockRelease(&PgArch->mutex);
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..34c8551288 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3141,24 +3142,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3175,6 +3158,26 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
+		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			if (PgArchStartupAllowed())
+				PgArchPID = StartArchiver();
+			continue;
+		}
+
 		/* Was it the system logger?  If so, try to start a new one */
 		if (pid == SysLoggerPID)
 		{
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..d053bf1564 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,9 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Wed_Mar_10_17_51_37_2021_192)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v52-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v45 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index db0cfaa360..aabf9d73eb 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 0786fcf103..430d438303 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -354,6 +354,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Fri_Jan__8_10_24_34_2021_185)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v45-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v46 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index c87ffc6549..a1e51c5b99 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 0786fcf103..430d438303 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -354,6 +354,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Thu_Jan_14_15_14_25_2021_903)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v46-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v47 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index c87ffc6549..a1e51c5b99 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 683ab64f76..6cdaf3753d 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -355,6 +355,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Thu_Jan_21_12_03_48_2021_284)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v47-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v48 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..22e1cd244c 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3143,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3403,7 +3400,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,6 +3606,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3912,6 +3921,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5140,7 +5150,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5204,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5445,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..491747c113 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Fri_Mar__5_17_18_56_2021_497)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v48-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v49 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 174 +++--------------------
 src/backend/postmaster/postmaster.c      |  88 ++++++------
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 83 insertions(+), 232 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..e237cedaff 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,25 +79,17 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -105,121 +98,9 @@ static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +112,24 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..d9f8d82650 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3126,6 +3127,18 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  We treat it the same way to WAL receiver.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			continue;
+		}
+
 		/*
 		 * Was it the autovacuum launcher?	Normal exit can be ignored; we'll
 		 * start a new one at the next iteration of the postmaster's main
@@ -3141,24 +3154,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3403,7 +3398,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3604,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3904,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -4989,6 +4982,19 @@ SubPostmasterMain(int argc, char *argv[])
 
 		AuxiliaryProcessMain(argc - 2, argv + 2);	/* does not return */
 	}
+	if (strcmp(argv[1], "--forkarch") == 0)
+	{
+		/* Restore basic shared memory pointers */
+		InitShmemAccess(UsedShmemSegAddr);
+
+		/* Need a PGPROC to run CreateSharedMemoryAndSemaphores */
+		InitAuxiliaryProcess();
+
+		/* Attach process to shared data structures */
+		CreateSharedMemoryAndSemaphores();
+
+		PgArchiverMain(); /* does not return */
+	}
 	if (strcmp(argv[1], "--forkavlauncher") == 0)
 	{
 		/* Restore basic shared memory pointers */
@@ -5037,12 +5043,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5140,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5194,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5435,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d73890b228 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,8 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Tue_Mar__9_16_53_11_2021_575)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v49-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v50 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 174 +++--------------------
 src/backend/postmaster/postmaster.c      |  88 ++++++------
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 83 insertions(+), 232 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..e237cedaff 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,25 +79,17 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -105,121 +98,9 @@ static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +112,24 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..d9f8d82650 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3126,6 +3127,18 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  We treat it the same way to WAL receiver.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			continue;
+		}
+
 		/*
 		 * Was it the autovacuum launcher?	Normal exit can be ignored; we'll
 		 * start a new one at the next iteration of the postmaster's main
@@ -3141,24 +3154,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3403,7 +3398,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3604,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3904,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -4989,6 +4982,19 @@ SubPostmasterMain(int argc, char *argv[])
 
 		AuxiliaryProcessMain(argc - 2, argv + 2);	/* does not return */
 	}
+	if (strcmp(argv[1], "--forkarch") == 0)
+	{
+		/* Restore basic shared memory pointers */
+		InitShmemAccess(UsedShmemSegAddr);
+
+		/* Need a PGPROC to run CreateSharedMemoryAndSemaphores */
+		InitAuxiliaryProcess();
+
+		/* Attach process to shared data structures */
+		CreateSharedMemoryAndSemaphores();
+
+		PgArchiverMain(); /* does not return */
+	}
 	if (strcmp(argv[1], "--forkavlauncher") == 0)
 	{
 		/* Restore basic shared memory pointers */
@@ -5037,12 +5043,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5140,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5194,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5435,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d73890b228 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,8 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Tue_Mar__9_18_29_34_2021_806)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v50-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v51 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 194 ++++-------------------
 src/backend/postmaster/postmaster.c      |  83 +++++-----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 94 insertions(+), 236 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..c219780c60 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,13 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,148 +75,29 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +109,27 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +602,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ *  exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	ProcGlobal->archiverLatch = NULL;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..fd509869aa 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3141,24 +3142,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3175,6 +3158,26 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving of remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
+		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			if (PgArchStartupAllowed())
+				PgArchPID = StartArchiver();
+			continue;
+		}
+
 		/* Was it the system logger?  If so, try to start a new one */
 		if (pid == SysLoggerPID)
 		{
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d71700a565 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -350,6 +350,8 @@ typedef struct PROC_HDR
 	Latch	   *walwriterLatch;
 	/* Checkpointer process's latch */
 	Latch	   *checkpointerLatch;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 	/* Current shared estimate of appropriate spins_per_delay value */
 	int			spins_per_delay;
 	/* The proc of the Startup process, since not in ProcArray */
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Wed_Mar_10_12_10_39_2021_432)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v51-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v52 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 224 ++++++++---------------
 src/backend/postmaster/postmaster.c      |  83 ++++-----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  13 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 9 files changed, 139 insertions(+), 222 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..2558bcfb08 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,13 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +493,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..c399e6c267 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,68 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	Latch	*latch;		/* latch to wake the archiver up */
+	slock_t  mutex;		/* locks this struct */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size	size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
+	return size;
+}
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool	found;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver ", PgArchShmemSize(), &found);
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
+	if (!found)
 	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
+		SpinLockInit(&PgArch->mutex);
+		PgArch->latch = NULL;
 	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
 }
-#endif							/* EXEC_BACKEND */
-
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +144,48 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = MyLatch;
+	SpinLockRelease(&PgArch->mutex);
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	Latch	*latch;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
+	SpinLockAcquire(&PgArch->mutex);
+	latch = PgArch->latch;
+	SpinLockRelease(&PgArch->mutex);
 
-	errno = save_errno;
+	if (latch)
+		SetLatch(latch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +210,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +248,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +270,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +656,17 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ *  exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = NULL;
+	SpinLockRelease(&PgArch->mutex);
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..34c8551288 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3141,24 +3142,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3175,6 +3158,26 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
+		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			if (PgArchStartupAllowed())
+				PgArchPID = StartArchiver();
+			continue;
+		}
+
 		/* Was it the system logger?  If so, try to start a new one */
 		if (pid == SysLoggerPID)
 		{
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..d053bf1564 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,9 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Wed_Mar_10_17_51_37_2021_192)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v52-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v45 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index db0cfaa360..aabf9d73eb 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 0786fcf103..430d438303 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -354,6 +354,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Fri_Jan__8_10_24_34_2021_185)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v45-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v46 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index c87ffc6549..a1e51c5b99 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 0786fcf103..430d438303 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -354,6 +354,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Thu_Jan_14_15_14_25_2021_903)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v46-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v47 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index c87ffc6549..a1e51c5b99 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 683ab64f76..6cdaf3753d 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -355,6 +355,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Thu_Jan_21_12_03_48_2021_284)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v47-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v48 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..22e1cd244c 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3143,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3403,7 +3400,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,6 +3606,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3912,6 +3921,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5140,7 +5150,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5204,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5445,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..491747c113 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Fri_Mar__5_17_18_56_2021_497)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v48-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v49 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 174 +++--------------------
 src/backend/postmaster/postmaster.c      |  88 ++++++------
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 83 insertions(+), 232 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..e237cedaff 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,25 +79,17 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -105,121 +98,9 @@ static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +112,24 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..d9f8d82650 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3126,6 +3127,18 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  We treat it the same way to WAL receiver.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			continue;
+		}
+
 		/*
 		 * Was it the autovacuum launcher?	Normal exit can be ignored; we'll
 		 * start a new one at the next iteration of the postmaster's main
@@ -3141,24 +3154,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3403,7 +3398,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3604,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3904,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -4989,6 +4982,19 @@ SubPostmasterMain(int argc, char *argv[])
 
 		AuxiliaryProcessMain(argc - 2, argv + 2);	/* does not return */
 	}
+	if (strcmp(argv[1], "--forkarch") == 0)
+	{
+		/* Restore basic shared memory pointers */
+		InitShmemAccess(UsedShmemSegAddr);
+
+		/* Need a PGPROC to run CreateSharedMemoryAndSemaphores */
+		InitAuxiliaryProcess();
+
+		/* Attach process to shared data structures */
+		CreateSharedMemoryAndSemaphores();
+
+		PgArchiverMain(); /* does not return */
+	}
 	if (strcmp(argv[1], "--forkavlauncher") == 0)
 	{
 		/* Restore basic shared memory pointers */
@@ -5037,12 +5043,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5140,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5194,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5435,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d73890b228 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,8 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Tue_Mar__9_16_53_11_2021_575)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v49-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v50 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 174 +++--------------------
 src/backend/postmaster/postmaster.c      |  88 ++++++------
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 83 insertions(+), 232 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..e237cedaff 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,25 +79,17 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -105,121 +98,9 @@ static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +112,24 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..d9f8d82650 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3126,6 +3127,18 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  We treat it the same way to WAL receiver.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			continue;
+		}
+
 		/*
 		 * Was it the autovacuum launcher?	Normal exit can be ignored; we'll
 		 * start a new one at the next iteration of the postmaster's main
@@ -3141,24 +3154,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3403,7 +3398,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3604,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3904,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -4989,6 +4982,19 @@ SubPostmasterMain(int argc, char *argv[])
 
 		AuxiliaryProcessMain(argc - 2, argv + 2);	/* does not return */
 	}
+	if (strcmp(argv[1], "--forkarch") == 0)
+	{
+		/* Restore basic shared memory pointers */
+		InitShmemAccess(UsedShmemSegAddr);
+
+		/* Need a PGPROC to run CreateSharedMemoryAndSemaphores */
+		InitAuxiliaryProcess();
+
+		/* Attach process to shared data structures */
+		CreateSharedMemoryAndSemaphores();
+
+		PgArchiverMain(); /* does not return */
+	}
 	if (strcmp(argv[1], "--forkavlauncher") == 0)
 	{
 		/* Restore basic shared memory pointers */
@@ -5037,12 +5043,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5140,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5194,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5435,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d73890b228 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,8 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Tue_Mar__9_18_29_34_2021_806)--
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Content-Transfer-Encoding: 7bit
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 filename="v50-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v51 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 194 ++++-------------------
 src/backend/postmaster/postmaster.c      |  83 +++++-----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 94 insertions(+), 236 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..c219780c60 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,13 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,148 +75,29 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +109,27 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +602,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ *  exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	ProcGlobal->archiverLatch = NULL;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..fd509869aa 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3141,24 +3142,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3175,6 +3158,26 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving of remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
+		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			if (PgArchStartupAllowed())
+				PgArchPID = StartArchiver();
+			continue;
+		}
+
 		/* Was it the system logger?  If so, try to start a new one */
 		if (pid == SysLoggerPID)
 		{
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d71700a565 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -350,6 +350,8 @@ typedef struct PROC_HDR
 	Latch	   *walwriterLatch;
 	/* Checkpointer process's latch */
 	Latch	   *checkpointerLatch;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 	/* Current shared estimate of appropriate spins_per_delay value */
 	int			spins_per_delay;
 	/* The proc of the Startup process, since not in ProcArray */
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Wed_Mar_10_12_10_39_2021_432)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
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 filename="v51-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v52 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 224 ++++++++---------------
 src/backend/postmaster/postmaster.c      |  83 ++++-----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  13 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 9 files changed, 139 insertions(+), 222 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..2558bcfb08 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,13 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +493,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..c399e6c267 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,68 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	Latch	*latch;		/* latch to wake the archiver up */
+	slock_t  mutex;		/* locks this struct */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size	size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
+	return size;
+}
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool	found;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver ", PgArchShmemSize(), &found);
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
+	if (!found)
 	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
+		SpinLockInit(&PgArch->mutex);
+		PgArch->latch = NULL;
 	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
 }
-#endif							/* EXEC_BACKEND */
-
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +144,48 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = MyLatch;
+	SpinLockRelease(&PgArch->mutex);
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	Latch	*latch;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
+	SpinLockAcquire(&PgArch->mutex);
+	latch = PgArch->latch;
+	SpinLockRelease(&PgArch->mutex);
 
-	errno = save_errno;
+	if (latch)
+		SetLatch(latch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +210,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +248,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +270,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +656,17 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ *  exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = NULL;
+	SpinLockRelease(&PgArch->mutex);
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..34c8551288 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3141,24 +3142,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3175,6 +3158,26 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
+		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			if (PgArchStartupAllowed())
+				PgArchPID = StartArchiver();
+			continue;
+		}
+
 		/* Was it the system logger?  If so, try to start a new one */
 		if (pid == SysLoggerPID)
 		{
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..d053bf1564 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,9 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Wed_Mar_10_17_51_37_2021_192)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v52-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v45 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index db0cfaa360..aabf9d73eb 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 0786fcf103..430d438303 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -354,6 +354,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Fri_Jan__8_10_24_34_2021_185)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v45-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v46 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index c87ffc6549..a1e51c5b99 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 0786fcf103..430d438303 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -354,6 +354,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Thu_Jan_14_15_14_25_2021_903)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v46-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v47 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index c87ffc6549..a1e51c5b99 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 683ab64f76..6cdaf3753d 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -355,6 +355,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Thu_Jan_21_12_03_48_2021_284)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v47-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v48 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..22e1cd244c 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3143,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3403,7 +3400,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,6 +3606,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3912,6 +3921,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5140,7 +5150,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5204,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5445,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..491747c113 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Fri_Mar__5_17_18_56_2021_497)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v48-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v49 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 174 +++--------------------
 src/backend/postmaster/postmaster.c      |  88 ++++++------
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 83 insertions(+), 232 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..e237cedaff 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,25 +79,17 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -105,121 +98,9 @@ static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +112,24 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..d9f8d82650 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3126,6 +3127,18 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  We treat it the same way to WAL receiver.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			continue;
+		}
+
 		/*
 		 * Was it the autovacuum launcher?	Normal exit can be ignored; we'll
 		 * start a new one at the next iteration of the postmaster's main
@@ -3141,24 +3154,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3403,7 +3398,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3604,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3904,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -4989,6 +4982,19 @@ SubPostmasterMain(int argc, char *argv[])
 
 		AuxiliaryProcessMain(argc - 2, argv + 2);	/* does not return */
 	}
+	if (strcmp(argv[1], "--forkarch") == 0)
+	{
+		/* Restore basic shared memory pointers */
+		InitShmemAccess(UsedShmemSegAddr);
+
+		/* Need a PGPROC to run CreateSharedMemoryAndSemaphores */
+		InitAuxiliaryProcess();
+
+		/* Attach process to shared data structures */
+		CreateSharedMemoryAndSemaphores();
+
+		PgArchiverMain(); /* does not return */
+	}
 	if (strcmp(argv[1], "--forkavlauncher") == 0)
 	{
 		/* Restore basic shared memory pointers */
@@ -5037,12 +5043,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5140,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5194,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5435,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d73890b228 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,8 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Tue_Mar__9_16_53_11_2021_575)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v49-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v50 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 174 +++--------------------
 src/backend/postmaster/postmaster.c      |  88 ++++++------
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 83 insertions(+), 232 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..e237cedaff 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,25 +79,17 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -105,121 +98,9 @@ static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +112,24 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..d9f8d82650 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3126,6 +3127,18 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  We treat it the same way to WAL receiver.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			continue;
+		}
+
 		/*
 		 * Was it the autovacuum launcher?	Normal exit can be ignored; we'll
 		 * start a new one at the next iteration of the postmaster's main
@@ -3141,24 +3154,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3403,7 +3398,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3604,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3904,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -4989,6 +4982,19 @@ SubPostmasterMain(int argc, char *argv[])
 
 		AuxiliaryProcessMain(argc - 2, argv + 2);	/* does not return */
 	}
+	if (strcmp(argv[1], "--forkarch") == 0)
+	{
+		/* Restore basic shared memory pointers */
+		InitShmemAccess(UsedShmemSegAddr);
+
+		/* Need a PGPROC to run CreateSharedMemoryAndSemaphores */
+		InitAuxiliaryProcess();
+
+		/* Attach process to shared data structures */
+		CreateSharedMemoryAndSemaphores();
+
+		PgArchiverMain(); /* does not return */
+	}
 	if (strcmp(argv[1], "--forkavlauncher") == 0)
 	{
 		/* Restore basic shared memory pointers */
@@ -5037,12 +5043,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5140,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5194,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5435,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d73890b228 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,8 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Tue_Mar__9_18_29_34_2021_806)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v50-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v51 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 194 ++++-------------------
 src/backend/postmaster/postmaster.c      |  83 +++++-----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 94 insertions(+), 236 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..c219780c60 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,13 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,148 +75,29 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +109,27 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +602,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ *  exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	ProcGlobal->archiverLatch = NULL;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..fd509869aa 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3141,24 +3142,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3175,6 +3158,26 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving of remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
+		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			if (PgArchStartupAllowed())
+				PgArchPID = StartArchiver();
+			continue;
+		}
+
 		/* Was it the system logger?  If so, try to start a new one */
 		if (pid == SysLoggerPID)
 		{
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d71700a565 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -350,6 +350,8 @@ typedef struct PROC_HDR
 	Latch	   *walwriterLatch;
 	/* Checkpointer process's latch */
 	Latch	   *checkpointerLatch;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 	/* Current shared estimate of appropriate spins_per_delay value */
 	int			spins_per_delay;
 	/* The proc of the Startup process, since not in ProcArray */
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Wed_Mar_10_12_10_39_2021_432)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v51-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v52 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 224 ++++++++---------------
 src/backend/postmaster/postmaster.c      |  83 ++++-----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  13 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 9 files changed, 139 insertions(+), 222 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..2558bcfb08 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,13 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +493,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..c399e6c267 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,68 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	Latch	*latch;		/* latch to wake the archiver up */
+	slock_t  mutex;		/* locks this struct */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size	size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
+	return size;
+}
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool	found;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver ", PgArchShmemSize(), &found);
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
+	if (!found)
 	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
+		SpinLockInit(&PgArch->mutex);
+		PgArch->latch = NULL;
 	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
 }
-#endif							/* EXEC_BACKEND */
-
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +144,48 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = MyLatch;
+	SpinLockRelease(&PgArch->mutex);
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	Latch	*latch;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
+	SpinLockAcquire(&PgArch->mutex);
+	latch = PgArch->latch;
+	SpinLockRelease(&PgArch->mutex);
 
-	errno = save_errno;
+	if (latch)
+		SetLatch(latch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +210,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +248,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +270,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +656,17 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ *  exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = NULL;
+	SpinLockRelease(&PgArch->mutex);
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..34c8551288 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3141,24 +3142,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3175,6 +3158,26 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
+		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			if (PgArchStartupAllowed())
+				PgArchPID = StartArchiver();
+			continue;
+		}
+
 		/* Was it the system logger?  If so, try to start a new one */
 		if (pid == SysLoggerPID)
 		{
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..d053bf1564 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,9 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Wed_Mar_10_17_51_37_2021_192)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v52-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v33 4/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index cdd586fcfb..ee3444284b 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -489,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 5480a024e0..d398ce6f03 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -319,6 +319,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -439,30 +442,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index 37be0e2bbb..063d1323ea 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	pqsignal(SIGQUIT, SignalHandlerForCrashExit);
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 160afe9f39..9de9396628 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -539,6 +539,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1785,7 +1786,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3068,7 +3069,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3203,20 +3204,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3464,7 +3461,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3669,6 +3666,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3941,6 +3950,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5216,7 +5226,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5259,16 +5269,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5501,6 +5501,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 5aa19d3f78..7acc48734e 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -187,6 +187,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index e917dfe92d..0783692c83 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -336,6 +336,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 1c67de2ede..54ce0b97d7 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 14fa127ab1..619b2f9c71 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index b3200874ca..e3ffc63f14 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index 56c5ec4481..c691acf8cd 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index ae4f573ab4..1a8a0c2e15 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -272,6 +272,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.18.2


----Next_Part(Fri_May_15_17_30_36_2020_111)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v33-0005-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v45 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index db0cfaa360..aabf9d73eb 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 0786fcf103..430d438303 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -354,6 +354,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Fri_Jan__8_10_24_34_2021_185)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v45-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v46 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index c87ffc6549..a1e51c5b99 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 0786fcf103..430d438303 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -354,6 +354,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Thu_Jan_14_15_14_25_2021_903)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v46-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v47 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index c87ffc6549..a1e51c5b99 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 683ab64f76..6cdaf3753d 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -355,6 +355,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Thu_Jan_21_12_03_48_2021_284)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v47-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v48 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..22e1cd244c 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3143,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3403,7 +3400,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,6 +3606,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3912,6 +3921,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5140,7 +5150,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5204,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5445,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..491747c113 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Fri_Mar__5_17_18_56_2021_497)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v48-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v49 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 174 +++--------------------
 src/backend/postmaster/postmaster.c      |  88 ++++++------
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 83 insertions(+), 232 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..e237cedaff 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,25 +79,17 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -105,121 +98,9 @@ static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +112,24 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..d9f8d82650 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3126,6 +3127,18 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  We treat it the same way to WAL receiver.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			continue;
+		}
+
 		/*
 		 * Was it the autovacuum launcher?	Normal exit can be ignored; we'll
 		 * start a new one at the next iteration of the postmaster's main
@@ -3141,24 +3154,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3403,7 +3398,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3604,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3904,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -4989,6 +4982,19 @@ SubPostmasterMain(int argc, char *argv[])
 
 		AuxiliaryProcessMain(argc - 2, argv + 2);	/* does not return */
 	}
+	if (strcmp(argv[1], "--forkarch") == 0)
+	{
+		/* Restore basic shared memory pointers */
+		InitShmemAccess(UsedShmemSegAddr);
+
+		/* Need a PGPROC to run CreateSharedMemoryAndSemaphores */
+		InitAuxiliaryProcess();
+
+		/* Attach process to shared data structures */
+		CreateSharedMemoryAndSemaphores();
+
+		PgArchiverMain(); /* does not return */
+	}
 	if (strcmp(argv[1], "--forkavlauncher") == 0)
 	{
 		/* Restore basic shared memory pointers */
@@ -5037,12 +5043,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5140,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5194,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5435,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d73890b228 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,8 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Tue_Mar__9_16_53_11_2021_575)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v49-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v50 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 174 +++--------------------
 src/backend/postmaster/postmaster.c      |  88 ++++++------
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 83 insertions(+), 232 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..e237cedaff 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,25 +79,17 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -105,121 +98,9 @@ static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +112,24 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..d9f8d82650 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3126,6 +3127,18 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  We treat it the same way to WAL receiver.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			continue;
+		}
+
 		/*
 		 * Was it the autovacuum launcher?	Normal exit can be ignored; we'll
 		 * start a new one at the next iteration of the postmaster's main
@@ -3141,24 +3154,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3403,7 +3398,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3604,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3904,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -4989,6 +4982,19 @@ SubPostmasterMain(int argc, char *argv[])
 
 		AuxiliaryProcessMain(argc - 2, argv + 2);	/* does not return */
 	}
+	if (strcmp(argv[1], "--forkarch") == 0)
+	{
+		/* Restore basic shared memory pointers */
+		InitShmemAccess(UsedShmemSegAddr);
+
+		/* Need a PGPROC to run CreateSharedMemoryAndSemaphores */
+		InitAuxiliaryProcess();
+
+		/* Attach process to shared data structures */
+		CreateSharedMemoryAndSemaphores();
+
+		PgArchiverMain(); /* does not return */
+	}
 	if (strcmp(argv[1], "--forkavlauncher") == 0)
 	{
 		/* Restore basic shared memory pointers */
@@ -5037,12 +5043,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5140,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5194,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5435,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d73890b228 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,8 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Tue_Mar__9_18_29_34_2021_806)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v50-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v51 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 194 ++++-------------------
 src/backend/postmaster/postmaster.c      |  83 +++++-----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 94 insertions(+), 236 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..c219780c60 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,13 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,148 +75,29 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +109,27 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +602,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ *  exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	ProcGlobal->archiverLatch = NULL;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..fd509869aa 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3141,24 +3142,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3175,6 +3158,26 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving of remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
+		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			if (PgArchStartupAllowed())
+				PgArchPID = StartArchiver();
+			continue;
+		}
+
 		/* Was it the system logger?  If so, try to start a new one */
 		if (pid == SysLoggerPID)
 		{
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d71700a565 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -350,6 +350,8 @@ typedef struct PROC_HDR
 	Latch	   *walwriterLatch;
 	/* Checkpointer process's latch */
 	Latch	   *checkpointerLatch;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 	/* Current shared estimate of appropriate spins_per_delay value */
 	int			spins_per_delay;
 	/* The proc of the Startup process, since not in ProcArray */
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Wed_Mar_10_12_10_39_2021_432)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v51-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v52 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 224 ++++++++---------------
 src/backend/postmaster/postmaster.c      |  83 ++++-----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  13 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 9 files changed, 139 insertions(+), 222 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..2558bcfb08 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,13 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +493,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..c399e6c267 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,68 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	Latch	*latch;		/* latch to wake the archiver up */
+	slock_t  mutex;		/* locks this struct */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size	size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
+	return size;
+}
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool	found;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver ", PgArchShmemSize(), &found);
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
+	if (!found)
 	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
+		SpinLockInit(&PgArch->mutex);
+		PgArch->latch = NULL;
 	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
 }
-#endif							/* EXEC_BACKEND */
-
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +144,48 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = MyLatch;
+	SpinLockRelease(&PgArch->mutex);
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	Latch	*latch;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
+	SpinLockAcquire(&PgArch->mutex);
+	latch = PgArch->latch;
+	SpinLockRelease(&PgArch->mutex);
 
-	errno = save_errno;
+	if (latch)
+		SetLatch(latch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +210,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +248,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +270,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +656,17 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ *  exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = NULL;
+	SpinLockRelease(&PgArch->mutex);
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..34c8551288 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3141,24 +3142,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3175,6 +3158,26 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
+		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			if (PgArchStartupAllowed())
+				PgArchPID = StartArchiver();
+			continue;
+		}
+
 		/* Was it the system logger?  If so, try to start a new one */
 		if (pid == SysLoggerPID)
 		{
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..d053bf1564 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,9 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Wed_Mar_10_17_51_37_2021_192)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v52-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v48 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..22e1cd244c 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3143,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3403,7 +3400,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,6 +3606,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3912,6 +3921,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5140,7 +5150,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5204,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5445,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..491747c113 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Fri_Mar__5_17_18_56_2021_497)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v48-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v49 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 174 +++--------------------
 src/backend/postmaster/postmaster.c      |  88 ++++++------
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 83 insertions(+), 232 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..e237cedaff 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,25 +79,17 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -105,121 +98,9 @@ static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +112,24 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..d9f8d82650 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3126,6 +3127,18 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  We treat it the same way to WAL receiver.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			continue;
+		}
+
 		/*
 		 * Was it the autovacuum launcher?	Normal exit can be ignored; we'll
 		 * start a new one at the next iteration of the postmaster's main
@@ -3141,24 +3154,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3403,7 +3398,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3604,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3904,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -4989,6 +4982,19 @@ SubPostmasterMain(int argc, char *argv[])
 
 		AuxiliaryProcessMain(argc - 2, argv + 2);	/* does not return */
 	}
+	if (strcmp(argv[1], "--forkarch") == 0)
+	{
+		/* Restore basic shared memory pointers */
+		InitShmemAccess(UsedShmemSegAddr);
+
+		/* Need a PGPROC to run CreateSharedMemoryAndSemaphores */
+		InitAuxiliaryProcess();
+
+		/* Attach process to shared data structures */
+		CreateSharedMemoryAndSemaphores();
+
+		PgArchiverMain(); /* does not return */
+	}
 	if (strcmp(argv[1], "--forkavlauncher") == 0)
 	{
 		/* Restore basic shared memory pointers */
@@ -5037,12 +5043,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5140,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5194,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5435,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d73890b228 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,8 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Tue_Mar__9_16_53_11_2021_575)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v49-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v50 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 174 +++--------------------
 src/backend/postmaster/postmaster.c      |  88 ++++++------
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 83 insertions(+), 232 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..e237cedaff 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,25 +79,17 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -105,121 +98,9 @@ static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +112,24 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..d9f8d82650 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3126,6 +3127,18 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  We treat it the same way to WAL receiver.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			continue;
+		}
+
 		/*
 		 * Was it the autovacuum launcher?	Normal exit can be ignored; we'll
 		 * start a new one at the next iteration of the postmaster's main
@@ -3141,24 +3154,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3403,7 +3398,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3604,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3904,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -4989,6 +4982,19 @@ SubPostmasterMain(int argc, char *argv[])
 
 		AuxiliaryProcessMain(argc - 2, argv + 2);	/* does not return */
 	}
+	if (strcmp(argv[1], "--forkarch") == 0)
+	{
+		/* Restore basic shared memory pointers */
+		InitShmemAccess(UsedShmemSegAddr);
+
+		/* Need a PGPROC to run CreateSharedMemoryAndSemaphores */
+		InitAuxiliaryProcess();
+
+		/* Attach process to shared data structures */
+		CreateSharedMemoryAndSemaphores();
+
+		PgArchiverMain(); /* does not return */
+	}
 	if (strcmp(argv[1], "--forkavlauncher") == 0)
 	{
 		/* Restore basic shared memory pointers */
@@ -5037,12 +5043,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5140,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5194,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5435,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d73890b228 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,8 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Tue_Mar__9_18_29_34_2021_806)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v50-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v51 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 194 ++++-------------------
 src/backend/postmaster/postmaster.c      |  83 +++++-----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 94 insertions(+), 236 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..c219780c60 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,13 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,148 +75,29 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +109,27 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +602,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ *  exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	ProcGlobal->archiverLatch = NULL;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..fd509869aa 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3141,24 +3142,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3175,6 +3158,26 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving of remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
+		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			if (PgArchStartupAllowed())
+				PgArchPID = StartArchiver();
+			continue;
+		}
+
 		/* Was it the system logger?  If so, try to start a new one */
 		if (pid == SysLoggerPID)
 		{
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d71700a565 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -350,6 +350,8 @@ typedef struct PROC_HDR
 	Latch	   *walwriterLatch;
 	/* Checkpointer process's latch */
 	Latch	   *checkpointerLatch;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 	/* Current shared estimate of appropriate spins_per_delay value */
 	int			spins_per_delay;
 	/* The proc of the Startup process, since not in ProcArray */
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Wed_Mar_10_12_10_39_2021_432)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v51-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v52 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 224 ++++++++---------------
 src/backend/postmaster/postmaster.c      |  83 ++++-----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  13 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 9 files changed, 139 insertions(+), 222 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..2558bcfb08 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,13 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +493,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..c399e6c267 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,68 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	Latch	*latch;		/* latch to wake the archiver up */
+	slock_t  mutex;		/* locks this struct */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size	size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
+	return size;
+}
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool	found;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver ", PgArchShmemSize(), &found);
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
+	if (!found)
 	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
+		SpinLockInit(&PgArch->mutex);
+		PgArch->latch = NULL;
 	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
 }
-#endif							/* EXEC_BACKEND */
-
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +144,48 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = MyLatch;
+	SpinLockRelease(&PgArch->mutex);
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	Latch	*latch;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
+	SpinLockAcquire(&PgArch->mutex);
+	latch = PgArch->latch;
+	SpinLockRelease(&PgArch->mutex);
 
-	errno = save_errno;
+	if (latch)
+		SetLatch(latch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +210,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +248,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +270,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +656,17 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ *  exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = NULL;
+	SpinLockRelease(&PgArch->mutex);
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..34c8551288 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3141,24 +3142,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3175,6 +3158,26 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
+		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			if (PgArchStartupAllowed())
+				PgArchPID = StartArchiver();
+			continue;
+		}
+
 		/* Was it the system logger?  If so, try to start a new one */
 		if (pid == SysLoggerPID)
 		{
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..d053bf1564 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,9 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Wed_Mar_10_17_51_37_2021_192)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v52-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v29 4/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlog.c        |  46 ++++++++++
 src/backend/access/transam/xlogarchive.c |   2 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++---
 src/backend/postmaster/pgarch.c          | 102 ++++-------------------
 src/backend/postmaster/postmaster.c      |  53 ++++++------
 src/include/access/xlog.h                |   2 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 10 files changed, 108 insertions(+), 127 deletions(-)

diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 977d448f50..d75a257da2 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -684,6 +684,13 @@ typedef struct XLogCtlData
 	 */
 	Latch		recoveryWakeupLatch;
 
+	/*
+	 * archiverWakeupLatch is used to wake up the archiver process to process
+	 * completed WAL segments, if it is waiting for WAL to arrive.  Protected
+	 * by info_lck.
+	 */
+	Latch	   *archiverWakeupLatch;
+
 	/*
 	 * During recovery, we keep a copy of the latest checkpoint record here.
 	 * lastCheckPointRecPtr points to start of checkpoint record and
@@ -8450,6 +8457,45 @@ GetLastSegSwitchData(XLogRecPtr *lastSwitchLSN)
 	return result;
 }
 
+/*
+ * XLogArchiveWakeupStart - Set up archiver wakeup stuff
+ */
+void
+XLogArchiveWakeupStart(void)
+{
+	SpinLockAcquire(&XLogCtl->info_lck);
+	Assert(XLogCtl->archiverWakeupLatch == NULL);
+	XLogCtl->archiverWakeupLatch = MyLatch;
+	SpinLockRelease(&XLogCtl->info_lck);
+}
+
+/*
+ * XLogArchiveWakeupEnd - Clean up archiver wakeup stuff
+ */
+void
+XLogArchiveWakeupEnd(void)
+{
+	SpinLockAcquire(&XLogCtl->info_lck);
+	XLogCtl->archiverWakeupLatch = NULL;
+	SpinLockRelease(&XLogCtl->info_lck);
+}
+
+/*
+ * XLogWakeupArchiver - Wake up archiver process
+ */
+void
+XLogArchiveWakeup(void)
+{
+	Latch *latch;
+
+	SpinLockAcquire(&XLogCtl->info_lck);
+	latch = XLogCtl->archiverWakeupLatch;
+	SpinLockRelease(&XLogCtl->info_lck);
+
+	if (latch)
+		SetLatch(latch);
+}
+
 /*
  * This must be called ONCE during postmaster or standalone-backend shutdown
  */
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index d62c12310a..d6c8bcce8b 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -490,7 +490,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		XLogArchiveWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 5480a024e0..d398ce6f03 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -319,6 +319,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -439,30 +442,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index 37be0e2bbb..6fe7a136ba 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,7 +79,6 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
@@ -95,8 +95,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +108,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +141,21 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
+/* Clean up notification stuff on exit */
+static void
+PgArchiverKill(int code, Datum arg)
+{
+	XLogArchiveWakeupEnd();
+}
+
 /*
  * PgArchiverMain
  *
  *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
  *	since we don't use 'em, it hardly matters...
  */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,7 +167,7 @@ PgArchiverMain(int argc, char *argv[])
 	pqsignal(SIGQUIT, SignalHandlerForCrashExit);
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
@@ -240,24 +176,14 @@ PgArchiverMain(int argc, char *argv[])
 	MyBackendType = B_ARCHIVER;
 	init_ps_display(NULL);
 
+	XLogArchiveWakeupStart();
+	on_shmem_exit(PgArchiverKill, 0);
+	
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 73d278f3b2..a4b9d212a2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -146,7 +146,8 @@
 #define BACKEND_TYPE_AUTOVAC	0x0002	/* autovacuum worker process */
 #define BACKEND_TYPE_WALSND		0x0004	/* walsender process */
 #define BACKEND_TYPE_BGWORKER	0x0008	/* bgworker process */
-#define BACKEND_TYPE_ALL		0x000F	/* OR of all the above */
+#define BACKEND_TYPE_ARCHIVER	0x0010	/* archiver process */
+#define BACKEND_TYPE_ALL		0x001F	/* OR of all the above */
 
 #define BACKEND_TYPE_WORKER		(BACKEND_TYPE_AUTOVAC | BACKEND_TYPE_BGWORKER)
 
@@ -539,6 +540,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1785,7 +1787,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3055,7 +3057,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3190,20 +3192,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3451,7 +3449,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3656,6 +3654,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3928,6 +3938,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5208,7 +5219,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5251,16 +5262,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5493,6 +5494,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 9ec7b31cce..c0e149d526 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -313,6 +313,8 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 1c67de2ede..54ce0b97d7 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 14fa127ab1..619b2f9c71 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index b3200874ca..e3ffc63f14 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index 56c5ec4481..c691acf8cd 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
-- 
2.18.2


----Next_Part(Wed_Apr__1_15_15_11_2020_923)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v29-0005-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v30 4/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlog.c        |  46 +++++++++
 src/backend/access/transam/xlogarchive.c |   2 +-
 src/backend/bootstrap/bootstrap.c        |  22 +++--
 src/backend/postmaster/pgarch.c          | 115 ++++-------------------
 src/backend/postmaster/postmaster.c      |  53 ++++++-----
 src/include/access/xlog.h                |   2 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 10 files changed, 112 insertions(+), 136 deletions(-)

diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 977d448f50..d75a257da2 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -684,6 +684,13 @@ typedef struct XLogCtlData
 	 */
 	Latch		recoveryWakeupLatch;
 
+	/*
+	 * archiverWakeupLatch is used to wake up the archiver process to process
+	 * completed WAL segments, if it is waiting for WAL to arrive.  Protected
+	 * by info_lck.
+	 */
+	Latch	   *archiverWakeupLatch;
+
 	/*
 	 * During recovery, we keep a copy of the latest checkpoint record here.
 	 * lastCheckPointRecPtr points to start of checkpoint record and
@@ -8450,6 +8457,45 @@ GetLastSegSwitchData(XLogRecPtr *lastSwitchLSN)
 	return result;
 }
 
+/*
+ * XLogArchiveWakeupStart - Set up archiver wakeup stuff
+ */
+void
+XLogArchiveWakeupStart(void)
+{
+	SpinLockAcquire(&XLogCtl->info_lck);
+	Assert(XLogCtl->archiverWakeupLatch == NULL);
+	XLogCtl->archiverWakeupLatch = MyLatch;
+	SpinLockRelease(&XLogCtl->info_lck);
+}
+
+/*
+ * XLogArchiveWakeupEnd - Clean up archiver wakeup stuff
+ */
+void
+XLogArchiveWakeupEnd(void)
+{
+	SpinLockAcquire(&XLogCtl->info_lck);
+	XLogCtl->archiverWakeupLatch = NULL;
+	SpinLockRelease(&XLogCtl->info_lck);
+}
+
+/*
+ * XLogWakeupArchiver - Wake up archiver process
+ */
+void
+XLogArchiveWakeup(void)
+{
+	Latch *latch;
+
+	SpinLockAcquire(&XLogCtl->info_lck);
+	latch = XLogCtl->archiverWakeupLatch;
+	SpinLockRelease(&XLogCtl->info_lck);
+
+	if (latch)
+		SetLatch(latch);
+}
+
 /*
  * This must be called ONCE during postmaster or standalone-backend shutdown
  */
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index d62c12310a..d6c8bcce8b 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -490,7 +490,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		XLogArchiveWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 5480a024e0..d398ce6f03 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -319,6 +319,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -439,30 +442,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index 37be0e2bbb..7b66cb5613 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,7 +79,6 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
@@ -95,8 +95,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +108,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +141,16 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Clean up notification stuff on exit */
+static void
+PgArchiverKill(int code, Datum arg)
+{
+	XLogArchiveWakeupEnd();
+}
+
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +162,23 @@ PgArchiverMain(int argc, char *argv[])
 	pqsignal(SIGQUIT, SignalHandlerForCrashExit);
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
-
+	XLogArchiveWakeupStart();
+	on_shmem_exit(PgArchiverKill, 0);
+	
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 73d278f3b2..a4b9d212a2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -146,7 +146,8 @@
 #define BACKEND_TYPE_AUTOVAC	0x0002	/* autovacuum worker process */
 #define BACKEND_TYPE_WALSND		0x0004	/* walsender process */
 #define BACKEND_TYPE_BGWORKER	0x0008	/* bgworker process */
-#define BACKEND_TYPE_ALL		0x000F	/* OR of all the above */
+#define BACKEND_TYPE_ARCHIVER	0x0010	/* archiver process */
+#define BACKEND_TYPE_ALL		0x001F	/* OR of all the above */
 
 #define BACKEND_TYPE_WORKER		(BACKEND_TYPE_AUTOVAC | BACKEND_TYPE_BGWORKER)
 
@@ -539,6 +540,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1785,7 +1787,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3055,7 +3057,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3190,20 +3192,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3451,7 +3449,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3656,6 +3654,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3928,6 +3938,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5208,7 +5219,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5251,16 +5262,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5493,6 +5494,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 9ec7b31cce..c0e149d526 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -313,6 +313,8 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 1c67de2ede..54ce0b97d7 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 14fa127ab1..619b2f9c71 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index b3200874ca..e3ffc63f14 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index 56c5ec4481..c691acf8cd 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
-- 
2.18.2


----Next_Part(Wed_Apr__1_17_37_23_2020_570)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v30-0005-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v31 4/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index d62c12310a..2f8672ac0c 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -489,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 5480a024e0..d398ce6f03 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -319,6 +319,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -439,30 +442,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index 37be0e2bbb..063d1323ea 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	pqsignal(SIGQUIT, SignalHandlerForCrashExit);
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 73d278f3b2..e97995f973 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -539,6 +539,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1785,7 +1786,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3055,7 +3056,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3190,20 +3191,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3451,7 +3448,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3656,6 +3653,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3928,6 +3937,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5208,7 +5218,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5251,16 +5261,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5493,6 +5493,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 9938cddb57..af4599bd82 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -187,6 +187,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 9ec7b31cce..4435df82b6 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -313,6 +313,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 1c67de2ede..54ce0b97d7 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 14fa127ab1..619b2f9c71 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index b3200874ca..e3ffc63f14 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index 56c5ec4481..c691acf8cd 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index d21780108b..a87e7dc711 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -272,6 +272,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.18.2


----Next_Part(Fri_Apr__3_17_31_17_2020_104)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v31-0005-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v32 4/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index d62c12310a..2f8672ac0c 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -489,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 5480a024e0..d398ce6f03 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -319,6 +319,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -439,30 +442,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index 37be0e2bbb..063d1323ea 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	pqsignal(SIGQUIT, SignalHandlerForCrashExit);
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 73d278f3b2..e97995f973 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -539,6 +539,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1785,7 +1786,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3055,7 +3056,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3190,20 +3191,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3451,7 +3448,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3656,6 +3653,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3928,6 +3937,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5208,7 +5218,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5251,16 +5261,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5493,6 +5493,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 9938cddb57..af4599bd82 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -187,6 +187,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 9ec7b31cce..4435df82b6 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -313,6 +313,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 1c67de2ede..54ce0b97d7 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 14fa127ab1..619b2f9c71 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index b3200874ca..e3ffc63f14 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index 56c5ec4481..c691acf8cd 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index d21780108b..a87e7dc711 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -272,6 +272,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.18.2


----Next_Part(Tue_Apr__7_16_38_17_2020_299)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v32-0005-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v33 4/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 55becd65d4..2417de72a0 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -489,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 5480a024e0..d398ce6f03 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -319,6 +319,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -439,30 +442,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index 37be0e2bbb..063d1323ea 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	pqsignal(SIGQUIT, SignalHandlerForCrashExit);
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 0578e92ba9..2687d2af47 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -539,6 +539,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1785,7 +1786,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3055,7 +3056,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3190,20 +3191,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3451,7 +3448,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3656,6 +3653,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3928,6 +3937,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5203,7 +5213,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5246,16 +5256,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5488,6 +5488,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 5aa19d3f78..7acc48734e 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -187,6 +187,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 0a12afb59e..099da8cd76 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -336,6 +336,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 1c67de2ede..54ce0b97d7 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 14fa127ab1..619b2f9c71 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index b3200874ca..e3ffc63f14 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index 56c5ec4481..c691acf8cd 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index ae4f573ab4..1a8a0c2e15 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -272,6 +272,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.18.2


----Next_Part(Thu_Apr_30_13_22_05_2020_409)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v33-0005-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v25 4/8] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/bootstrap/bootstrap.c   | 22 +++++----
 src/backend/postmaster/pgarch.c     | 75 +----------------------------
 src/backend/postmaster/postmaster.c | 43 +++++++++++------
 src/include/miscadmin.h             |  2 +
 src/include/postmaster/pgarch.h     |  4 +-
 5 files changed, 46 insertions(+), 100 deletions(-)

diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 5480a024e0..d398ce6f03 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -319,6 +319,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -439,30 +442,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index 37be0e2bbb..4971b3ae42 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -78,7 +78,6 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
@@ -95,7 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
 static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
@@ -110,75 +108,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -218,8 +147,8 @@ pgarch_forkexec(void)
  *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
  *	since we don't use 'em, it hardly matters...
  */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 2b9ab32293..cab7fb5381 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -146,7 +146,8 @@
 #define BACKEND_TYPE_AUTOVAC	0x0002	/* autovacuum worker process */
 #define BACKEND_TYPE_WALSND		0x0004	/* walsender process */
 #define BACKEND_TYPE_BGWORKER	0x0008	/* bgworker process */
-#define BACKEND_TYPE_ALL		0x000F	/* OR of all the above */
+#define BACKEND_TYPE_ARCHIVER	0x0010	/* archiver process */
+#define BACKEND_TYPE_ALL		0x001F	/* OR of all the above */
 
 #define BACKEND_TYPE_WORKER		(BACKEND_TYPE_AUTOVAC | BACKEND_TYPE_BGWORKER)
 
@@ -539,6 +540,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1785,7 +1787,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3055,7 +3057,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3190,20 +3192,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3451,7 +3449,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3656,6 +3654,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3928,6 +3938,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5208,7 +5219,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5493,6 +5504,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 14fa127ab1..619b2f9c71 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index b3200874ca..e3ffc63f14 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
-- 
2.18.2


----Next_Part(Thu_Mar_19_20_30_04_2020_284)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v25-0005-Use-latch-instead-of-SIGUSR1-to-wake-up-archiver.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v48 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..22e1cd244c 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3143,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3403,7 +3400,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,6 +3606,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3912,6 +3921,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5140,7 +5150,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5204,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5445,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..491747c113 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Fri_Mar__5_17_18_56_2021_497)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v48-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v49 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 174 +++--------------------
 src/backend/postmaster/postmaster.c      |  88 ++++++------
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 83 insertions(+), 232 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..e237cedaff 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,25 +79,17 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -105,121 +98,9 @@ static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +112,24 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..d9f8d82650 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3126,6 +3127,18 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  We treat it the same way to WAL receiver.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			continue;
+		}
+
 		/*
 		 * Was it the autovacuum launcher?	Normal exit can be ignored; we'll
 		 * start a new one at the next iteration of the postmaster's main
@@ -3141,24 +3154,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3403,7 +3398,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3604,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3904,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -4989,6 +4982,19 @@ SubPostmasterMain(int argc, char *argv[])
 
 		AuxiliaryProcessMain(argc - 2, argv + 2);	/* does not return */
 	}
+	if (strcmp(argv[1], "--forkarch") == 0)
+	{
+		/* Restore basic shared memory pointers */
+		InitShmemAccess(UsedShmemSegAddr);
+
+		/* Need a PGPROC to run CreateSharedMemoryAndSemaphores */
+		InitAuxiliaryProcess();
+
+		/* Attach process to shared data structures */
+		CreateSharedMemoryAndSemaphores();
+
+		PgArchiverMain(); /* does not return */
+	}
 	if (strcmp(argv[1], "--forkavlauncher") == 0)
 	{
 		/* Restore basic shared memory pointers */
@@ -5037,12 +5043,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5140,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5194,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5435,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d73890b228 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,8 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Tue_Mar__9_16_53_11_2021_575)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v49-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v50 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 174 +++--------------------
 src/backend/postmaster/postmaster.c      |  88 ++++++------
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 83 insertions(+), 232 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..e237cedaff 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,25 +79,17 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -105,121 +98,9 @@ static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +112,24 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..d9f8d82650 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3126,6 +3127,18 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  We treat it the same way to WAL receiver.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			continue;
+		}
+
 		/*
 		 * Was it the autovacuum launcher?	Normal exit can be ignored; we'll
 		 * start a new one at the next iteration of the postmaster's main
@@ -3141,24 +3154,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3403,7 +3398,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3604,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3904,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -4989,6 +4982,19 @@ SubPostmasterMain(int argc, char *argv[])
 
 		AuxiliaryProcessMain(argc - 2, argv + 2);	/* does not return */
 	}
+	if (strcmp(argv[1], "--forkarch") == 0)
+	{
+		/* Restore basic shared memory pointers */
+		InitShmemAccess(UsedShmemSegAddr);
+
+		/* Need a PGPROC to run CreateSharedMemoryAndSemaphores */
+		InitAuxiliaryProcess();
+
+		/* Attach process to shared data structures */
+		CreateSharedMemoryAndSemaphores();
+
+		PgArchiverMain(); /* does not return */
+	}
 	if (strcmp(argv[1], "--forkavlauncher") == 0)
 	{
 		/* Restore basic shared memory pointers */
@@ -5037,12 +5043,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5140,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5194,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5435,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d73890b228 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,8 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Tue_Mar__9_18_29_34_2021_806)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v50-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v51 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 194 ++++-------------------
 src/backend/postmaster/postmaster.c      |  83 +++++-----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 94 insertions(+), 236 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..c219780c60 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,13 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,148 +75,29 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +109,27 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +602,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ *  exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	ProcGlobal->archiverLatch = NULL;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..fd509869aa 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3141,24 +3142,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3175,6 +3158,26 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving of remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
+		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			if (PgArchStartupAllowed())
+				PgArchPID = StartArchiver();
+			continue;
+		}
+
 		/* Was it the system logger?  If so, try to start a new one */
 		if (pid == SysLoggerPID)
 		{
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d71700a565 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -350,6 +350,8 @@ typedef struct PROC_HDR
 	Latch	   *walwriterLatch;
 	/* Checkpointer process's latch */
 	Latch	   *checkpointerLatch;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 	/* Current shared estimate of appropriate spins_per_delay value */
 	int			spins_per_delay;
 	/* The proc of the Startup process, since not in ProcArray */
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Wed_Mar_10_12_10_39_2021_432)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v51-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v52 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 224 ++++++++---------------
 src/backend/postmaster/postmaster.c      |  83 ++++-----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  13 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 9 files changed, 139 insertions(+), 222 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..2558bcfb08 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,13 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +493,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..c399e6c267 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,68 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	Latch	*latch;		/* latch to wake the archiver up */
+	slock_t  mutex;		/* locks this struct */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size	size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
+	return size;
+}
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool	found;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver ", PgArchShmemSize(), &found);
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
+	if (!found)
 	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
+		SpinLockInit(&PgArch->mutex);
+		PgArch->latch = NULL;
 	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
 }
-#endif							/* EXEC_BACKEND */
-
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +144,48 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = MyLatch;
+	SpinLockRelease(&PgArch->mutex);
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	Latch	*latch;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
+	SpinLockAcquire(&PgArch->mutex);
+	latch = PgArch->latch;
+	SpinLockRelease(&PgArch->mutex);
 
-	errno = save_errno;
+	if (latch)
+		SetLatch(latch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +210,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +248,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +270,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +656,17 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ *  exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = NULL;
+	SpinLockRelease(&PgArch->mutex);
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..34c8551288 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3141,24 +3142,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3175,6 +3158,26 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
+		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			if (PgArchStartupAllowed())
+				PgArchPID = StartArchiver();
+			continue;
+		}
+
 		/* Was it the system logger?  If so, try to start a new one */
 		if (pid == SysLoggerPID)
 		{
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..d053bf1564 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,9 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Wed_Mar_10_17_51_37_2021_192)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v52-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v43 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index f39dc4ddf1..d69e20961d 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index a7ed93fdc1..edda899554 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index ed1b65358d..e3a520def9 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 5d09822c81..8a4706a870 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -547,6 +547,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1787,7 +1788,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3041,7 +3042,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3176,20 +3177,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3437,7 +3434,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3642,6 +3639,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3938,6 +3947,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5185,7 +5195,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5230,16 +5240,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5481,6 +5481,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 7dc3911590..fc23539137 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -181,6 +181,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 221af87e71..65443063e8 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 1c67de2ede..54ce0b97d7 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 72e3352398..bba002ad24 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -418,6 +418,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -430,6 +431,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index b3200874ca..e3ffc63f14 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index 56c5ec4481..c691acf8cd 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index e77f76ae8a..a656910d02 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -354,6 +354,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Fri_Dec_11_16_50_03_2020_915)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v43-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v44 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index f39dc4ddf1..d69e20961d 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index a7ed93fdc1..edda899554 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index ed1b65358d..e3a520def9 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 5d09822c81..8a4706a870 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -547,6 +547,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1787,7 +1788,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3041,7 +3042,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3176,20 +3177,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3437,7 +3434,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3642,6 +3639,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3938,6 +3947,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5185,7 +5195,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5230,16 +5240,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5481,6 +5481,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 7dc3911590..fc23539137 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -181,6 +181,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 221af87e71..65443063e8 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 1c67de2ede..54ce0b97d7 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 72e3352398..bba002ad24 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -418,6 +418,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -430,6 +431,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index b3200874ca..e3ffc63f14 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index 56c5ec4481..c691acf8cd 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index e77f76ae8a..a656910d02 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -354,6 +354,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Mon_Dec_21_17_16_20_2020_608)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v44-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v45 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index db0cfaa360..aabf9d73eb 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 0786fcf103..430d438303 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -354,6 +354,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Fri_Jan__8_10_24_34_2021_185)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v45-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v46 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index c87ffc6549..a1e51c5b99 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 0786fcf103..430d438303 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -354,6 +354,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


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 filename="v46-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v47 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index c87ffc6549..a1e51c5b99 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 683ab64f76..6cdaf3753d 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -355,6 +355,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Thu_Jan_21_12_03_48_2021_284)--
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Content-Transfer-Encoding: 7bit
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 filename="v47-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v48 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..22e1cd244c 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3143,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3403,7 +3400,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,6 +3606,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3912,6 +3921,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5140,7 +5150,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5204,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5445,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..491747c113 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Fri_Mar__5_17_18_56_2021_497)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v48-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v49 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 174 +++--------------------
 src/backend/postmaster/postmaster.c      |  88 ++++++------
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 83 insertions(+), 232 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..e237cedaff 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,25 +79,17 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -105,121 +98,9 @@ static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +112,24 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..d9f8d82650 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3126,6 +3127,18 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  We treat it the same way to WAL receiver.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			continue;
+		}
+
 		/*
 		 * Was it the autovacuum launcher?	Normal exit can be ignored; we'll
 		 * start a new one at the next iteration of the postmaster's main
@@ -3141,24 +3154,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3403,7 +3398,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3604,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3904,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -4989,6 +4982,19 @@ SubPostmasterMain(int argc, char *argv[])
 
 		AuxiliaryProcessMain(argc - 2, argv + 2);	/* does not return */
 	}
+	if (strcmp(argv[1], "--forkarch") == 0)
+	{
+		/* Restore basic shared memory pointers */
+		InitShmemAccess(UsedShmemSegAddr);
+
+		/* Need a PGPROC to run CreateSharedMemoryAndSemaphores */
+		InitAuxiliaryProcess();
+
+		/* Attach process to shared data structures */
+		CreateSharedMemoryAndSemaphores();
+
+		PgArchiverMain(); /* does not return */
+	}
 	if (strcmp(argv[1], "--forkavlauncher") == 0)
 	{
 		/* Restore basic shared memory pointers */
@@ -5037,12 +5043,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5140,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5194,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5435,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d73890b228 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,8 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Tue_Mar__9_16_53_11_2021_575)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v49-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v50 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 174 +++--------------------
 src/backend/postmaster/postmaster.c      |  88 ++++++------
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 83 insertions(+), 232 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..e237cedaff 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,25 +79,17 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -105,121 +98,9 @@ static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +112,24 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..d9f8d82650 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3126,6 +3127,18 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  We treat it the same way to WAL receiver.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			continue;
+		}
+
 		/*
 		 * Was it the autovacuum launcher?	Normal exit can be ignored; we'll
 		 * start a new one at the next iteration of the postmaster's main
@@ -3141,24 +3154,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3403,7 +3398,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3604,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3904,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -4989,6 +4982,19 @@ SubPostmasterMain(int argc, char *argv[])
 
 		AuxiliaryProcessMain(argc - 2, argv + 2);	/* does not return */
 	}
+	if (strcmp(argv[1], "--forkarch") == 0)
+	{
+		/* Restore basic shared memory pointers */
+		InitShmemAccess(UsedShmemSegAddr);
+
+		/* Need a PGPROC to run CreateSharedMemoryAndSemaphores */
+		InitAuxiliaryProcess();
+
+		/* Attach process to shared data structures */
+		CreateSharedMemoryAndSemaphores();
+
+		PgArchiverMain(); /* does not return */
+	}
 	if (strcmp(argv[1], "--forkavlauncher") == 0)
 	{
 		/* Restore basic shared memory pointers */
@@ -5037,12 +5043,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5140,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5194,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5435,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d73890b228 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,8 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Tue_Mar__9_18_29_34_2021_806)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v50-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v51 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 194 ++++-------------------
 src/backend/postmaster/postmaster.c      |  83 +++++-----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 94 insertions(+), 236 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..c219780c60 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,13 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,148 +75,29 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +109,27 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +602,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ *  exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	ProcGlobal->archiverLatch = NULL;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..fd509869aa 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3141,24 +3142,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3175,6 +3158,26 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving of remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
+		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			if (PgArchStartupAllowed())
+				PgArchPID = StartArchiver();
+			continue;
+		}
+
 		/* Was it the system logger?  If so, try to start a new one */
 		if (pid == SysLoggerPID)
 		{
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d71700a565 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -350,6 +350,8 @@ typedef struct PROC_HDR
 	Latch	   *walwriterLatch;
 	/* Checkpointer process's latch */
 	Latch	   *checkpointerLatch;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 	/* Current shared estimate of appropriate spins_per_delay value */
 	int			spins_per_delay;
 	/* The proc of the Startup process, since not in ProcArray */
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Wed_Mar_10_12_10_39_2021_432)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v51-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v52 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 224 ++++++++---------------
 src/backend/postmaster/postmaster.c      |  83 ++++-----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  13 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 9 files changed, 139 insertions(+), 222 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..2558bcfb08 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,13 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +493,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..c399e6c267 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,68 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	Latch	*latch;		/* latch to wake the archiver up */
+	slock_t  mutex;		/* locks this struct */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size	size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
+	return size;
+}
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool	found;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver ", PgArchShmemSize(), &found);
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
+	if (!found)
 	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
+		SpinLockInit(&PgArch->mutex);
+		PgArch->latch = NULL;
 	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
 }
-#endif							/* EXEC_BACKEND */
-
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +144,48 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = MyLatch;
+	SpinLockRelease(&PgArch->mutex);
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	Latch	*latch;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
+	SpinLockAcquire(&PgArch->mutex);
+	latch = PgArch->latch;
+	SpinLockRelease(&PgArch->mutex);
 
-	errno = save_errno;
+	if (latch)
+		SetLatch(latch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +210,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +248,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +270,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +656,17 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ *  exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = NULL;
+	SpinLockRelease(&PgArch->mutex);
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..34c8551288 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3141,24 +3142,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3175,6 +3158,26 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
+		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			if (PgArchStartupAllowed())
+				PgArchPID = StartArchiver();
+			continue;
+		}
+
 		/* Was it the system logger?  If so, try to start a new one */
 		if (pid == SysLoggerPID)
 		{
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..d053bf1564 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,9 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Wed_Mar_10_17_51_37_2021_192)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v52-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v36 4/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 8f8734dc1d..2e6c322142 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -489,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 76b2f5066f..81bfaea869 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index 37be0e2bbb..063d1323ea 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	pqsignal(SIGQUIT, SignalHandlerForCrashExit);
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 42223c0f61..4c296dd214 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -554,6 +554,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1799,7 +1800,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3051,7 +3052,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3186,20 +3187,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3447,7 +3444,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3652,6 +3649,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3948,6 +3957,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5223,7 +5233,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5268,16 +5278,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5515,6 +5515,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index aa9fbd8054..9cc5226667 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -181,6 +181,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 221af87e71..65443063e8 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 1c67de2ede..54ce0b97d7 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 72e3352398..bba002ad24 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -418,6 +418,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -430,6 +431,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index b3200874ca..e3ffc63f14 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index 56c5ec4481..c691acf8cd 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 9c9a50ae45..de20520b8c 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -345,6 +345,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.18.4


----Next_Part(Tue_Sep__8_17_55_57_2020_197)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v36-0005-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v37 3/6] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 8f8734dc1d..2e6c322142 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -489,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 76b2f5066f..81bfaea869 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index ed1b65358d..e3a520def9 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 959e3b8873..b811c961a6 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -555,6 +555,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1800,7 +1801,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3054,7 +3055,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3189,20 +3190,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3450,7 +3447,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3655,6 +3652,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3951,6 +3960,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5230,7 +5240,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5275,16 +5285,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5526,6 +5526,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 88566bd9fa..746bed773e 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -181,6 +181,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 221af87e71..65443063e8 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 1c67de2ede..54ce0b97d7 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 72e3352398..bba002ad24 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -418,6 +418,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -430,6 +431,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index b3200874ca..e3ffc63f14 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index 56c5ec4481..c691acf8cd 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 9c9a50ae45..de20520b8c 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -345,6 +345,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.18.4


----Next_Part(Fri_Sep_25_09_27_26_2020_419)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v37-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v38 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index cae93ab69d..6908bec2f9 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -489,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 76b2f5066f..81bfaea869 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index ed1b65358d..e3a520def9 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 959e3b8873..b811c961a6 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -555,6 +555,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1800,7 +1801,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3054,7 +3055,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3189,20 +3190,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3450,7 +3447,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3655,6 +3652,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3951,6 +3960,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5230,7 +5240,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5275,16 +5285,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5526,6 +5526,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 88566bd9fa..746bed773e 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -181,6 +181,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 221af87e71..65443063e8 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 1c67de2ede..54ce0b97d7 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 72e3352398..bba002ad24 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -418,6 +418,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -430,6 +431,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index b3200874ca..e3ffc63f14 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index 56c5ec4481..c691acf8cd 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 9c9a50ae45..de20520b8c 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -345,6 +345,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.18.4


----Next_Part(Thu_Oct__1_09_07_22_2020_252)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v38-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v39 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index cae93ab69d..6908bec2f9 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -489,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 76b2f5066f..81bfaea869 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index ed1b65358d..e3a520def9 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 959e3b8873..b811c961a6 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -555,6 +555,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1800,7 +1801,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3054,7 +3055,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3189,20 +3190,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3450,7 +3447,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3655,6 +3652,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3951,6 +3960,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5230,7 +5240,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5275,16 +5285,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5526,6 +5526,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 88566bd9fa..746bed773e 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -181,6 +181,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 221af87e71..65443063e8 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 1c67de2ede..54ce0b97d7 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 72e3352398..bba002ad24 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -418,6 +418,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -430,6 +431,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index b3200874ca..e3ffc63f14 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index 56c5ec4481..c691acf8cd 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 9c9a50ae45..de20520b8c 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -345,6 +345,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.18.4


----Next_Part(Tue_Oct__6_10_06_44_2020_382)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v39-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v40 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index cae93ab69d..6908bec2f9 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -489,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index a7ed93fdc1..edda899554 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index ed1b65358d..e3a520def9 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 959e3b8873..b811c961a6 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -555,6 +555,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1800,7 +1801,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3054,7 +3055,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3189,20 +3190,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3450,7 +3447,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3655,6 +3652,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3951,6 +3960,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5230,7 +5240,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5275,16 +5285,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5526,6 +5526,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 88566bd9fa..746bed773e 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -181,6 +181,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 221af87e71..65443063e8 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 1c67de2ede..54ce0b97d7 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 72e3352398..bba002ad24 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -418,6 +418,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -430,6 +431,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index b3200874ca..e3ffc63f14 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index 56c5ec4481..c691acf8cd 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 9c9a50ae45..de20520b8c 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -345,6 +345,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.18.4


----Next_Part(Wed_Nov__4_17_39_10_2020_208)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v40-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v41 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index cae93ab69d..6908bec2f9 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -489,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index a7ed93fdc1..edda899554 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index ed1b65358d..e3a520def9 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 959e3b8873..b811c961a6 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -555,6 +555,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1800,7 +1801,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3054,7 +3055,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3189,20 +3190,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3450,7 +3447,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3655,6 +3652,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3951,6 +3960,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5230,7 +5240,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5275,16 +5285,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5526,6 +5526,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 88566bd9fa..746bed773e 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -181,6 +181,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 221af87e71..65443063e8 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 1c67de2ede..54ce0b97d7 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 72e3352398..bba002ad24 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -418,6 +418,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -430,6 +431,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index b3200874ca..e3ffc63f14 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index 56c5ec4481..c691acf8cd 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 9c9a50ae45..de20520b8c 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -345,6 +345,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.18.4


----Next_Part(Fri_Nov__6_09_27_56_2020_738)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v41-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v42 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index cae93ab69d..6908bec2f9 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -489,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index a7ed93fdc1..edda899554 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index ed1b65358d..e3a520def9 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index b7799ed1d2..a1dd6964e9 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -547,6 +547,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1785,7 +1786,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3039,7 +3040,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3174,20 +3175,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3435,7 +3432,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3640,6 +3637,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3936,6 +3945,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5177,7 +5187,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5222,16 +5232,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5473,6 +5473,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 88566bd9fa..746bed773e 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -181,6 +181,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 221af87e71..65443063e8 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 1c67de2ede..54ce0b97d7 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 72e3352398..bba002ad24 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -418,6 +418,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -430,6 +431,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index b3200874ca..e3ffc63f14 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index 56c5ec4481..c691acf8cd 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 9c9a50ae45..de20520b8c 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -345,6 +345,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.18.4


----Next_Part(Wed_Nov_11_10_07_22_2020_796)--
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Content-Transfer-Encoding: 7bit
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 filename="v42-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v45 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index db0cfaa360..aabf9d73eb 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 0786fcf103..430d438303 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -354,6 +354,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Fri_Jan__8_10_24_34_2021_185)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v45-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v46 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index c87ffc6549..a1e51c5b99 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 0786fcf103..430d438303 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -354,6 +354,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Thu_Jan_14_15_14_25_2021_903)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v46-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v47 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index c87ffc6549..a1e51c5b99 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 683ab64f76..6cdaf3753d 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -355,6 +355,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Thu_Jan_21_12_03_48_2021_284)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v47-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v48 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..22e1cd244c 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3143,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3403,7 +3400,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,6 +3606,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3912,6 +3921,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5140,7 +5150,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5204,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5445,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..491747c113 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Fri_Mar__5_17_18_56_2021_497)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v48-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v49 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 174 +++--------------------
 src/backend/postmaster/postmaster.c      |  88 ++++++------
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 83 insertions(+), 232 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..e237cedaff 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,25 +79,17 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -105,121 +98,9 @@ static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +112,24 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..d9f8d82650 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3126,6 +3127,18 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  We treat it the same way to WAL receiver.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			continue;
+		}
+
 		/*
 		 * Was it the autovacuum launcher?	Normal exit can be ignored; we'll
 		 * start a new one at the next iteration of the postmaster's main
@@ -3141,24 +3154,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3403,7 +3398,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3604,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3904,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -4989,6 +4982,19 @@ SubPostmasterMain(int argc, char *argv[])
 
 		AuxiliaryProcessMain(argc - 2, argv + 2);	/* does not return */
 	}
+	if (strcmp(argv[1], "--forkarch") == 0)
+	{
+		/* Restore basic shared memory pointers */
+		InitShmemAccess(UsedShmemSegAddr);
+
+		/* Need a PGPROC to run CreateSharedMemoryAndSemaphores */
+		InitAuxiliaryProcess();
+
+		/* Attach process to shared data structures */
+		CreateSharedMemoryAndSemaphores();
+
+		PgArchiverMain(); /* does not return */
+	}
 	if (strcmp(argv[1], "--forkavlauncher") == 0)
 	{
 		/* Restore basic shared memory pointers */
@@ -5037,12 +5043,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5140,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5194,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5435,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d73890b228 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,8 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Tue_Mar__9_16_53_11_2021_575)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v49-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v50 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 174 +++--------------------
 src/backend/postmaster/postmaster.c      |  88 ++++++------
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 83 insertions(+), 232 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..e237cedaff 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,25 +79,17 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -105,121 +98,9 @@ static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +112,24 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..d9f8d82650 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3126,6 +3127,18 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  We treat it the same way to WAL receiver.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			continue;
+		}
+
 		/*
 		 * Was it the autovacuum launcher?	Normal exit can be ignored; we'll
 		 * start a new one at the next iteration of the postmaster's main
@@ -3141,24 +3154,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3403,7 +3398,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3604,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3904,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -4989,6 +4982,19 @@ SubPostmasterMain(int argc, char *argv[])
 
 		AuxiliaryProcessMain(argc - 2, argv + 2);	/* does not return */
 	}
+	if (strcmp(argv[1], "--forkarch") == 0)
+	{
+		/* Restore basic shared memory pointers */
+		InitShmemAccess(UsedShmemSegAddr);
+
+		/* Need a PGPROC to run CreateSharedMemoryAndSemaphores */
+		InitAuxiliaryProcess();
+
+		/* Attach process to shared data structures */
+		CreateSharedMemoryAndSemaphores();
+
+		PgArchiverMain(); /* does not return */
+	}
 	if (strcmp(argv[1], "--forkavlauncher") == 0)
 	{
 		/* Restore basic shared memory pointers */
@@ -5037,12 +5043,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5140,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5194,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5435,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d73890b228 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,8 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Tue_Mar__9_18_29_34_2021_806)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v50-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v51 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 194 ++++-------------------
 src/backend/postmaster/postmaster.c      |  83 +++++-----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 94 insertions(+), 236 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..c219780c60 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,13 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,148 +75,29 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +109,27 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +602,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ *  exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	ProcGlobal->archiverLatch = NULL;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..fd509869aa 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3141,24 +3142,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3175,6 +3158,26 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving of remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
+		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			if (PgArchStartupAllowed())
+				PgArchPID = StartArchiver();
+			continue;
+		}
+
 		/* Was it the system logger?  If so, try to start a new one */
 		if (pid == SysLoggerPID)
 		{
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d71700a565 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -350,6 +350,8 @@ typedef struct PROC_HDR
 	Latch	   *walwriterLatch;
 	/* Checkpointer process's latch */
 	Latch	   *checkpointerLatch;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 	/* Current shared estimate of appropriate spins_per_delay value */
 	int			spins_per_delay;
 	/* The proc of the Startup process, since not in ProcArray */
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Wed_Mar_10_12_10_39_2021_432)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v51-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v52 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 224 ++++++++---------------
 src/backend/postmaster/postmaster.c      |  83 ++++-----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  13 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 9 files changed, 139 insertions(+), 222 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..2558bcfb08 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,13 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +493,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..c399e6c267 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,68 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	Latch	*latch;		/* latch to wake the archiver up */
+	slock_t  mutex;		/* locks this struct */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size	size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
+	return size;
+}
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool	found;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver ", PgArchShmemSize(), &found);
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
+	if (!found)
 	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
+		SpinLockInit(&PgArch->mutex);
+		PgArch->latch = NULL;
 	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
 }
-#endif							/* EXEC_BACKEND */
-
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +144,48 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = MyLatch;
+	SpinLockRelease(&PgArch->mutex);
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	Latch	*latch;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
+	SpinLockAcquire(&PgArch->mutex);
+	latch = PgArch->latch;
+	SpinLockRelease(&PgArch->mutex);
 
-	errno = save_errno;
+	if (latch)
+		SetLatch(latch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +210,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +248,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +270,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +656,17 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ *  exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = NULL;
+	SpinLockRelease(&PgArch->mutex);
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..34c8551288 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3141,24 +3142,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3175,6 +3158,26 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
+		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			if (PgArchStartupAllowed())
+				PgArchPID = StartArchiver();
+			continue;
+		}
+
 		/* Was it the system logger?  If so, try to start a new one */
 		if (pid == SysLoggerPID)
 		{
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..d053bf1564 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,9 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Wed_Mar_10_17_51_37_2021_192)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v52-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v34 4/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index cdd586fcfb..ee3444284b 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -489,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 5480a024e0..d398ce6f03 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -319,6 +319,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -439,30 +442,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index 37be0e2bbb..063d1323ea 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	pqsignal(SIGQUIT, SignalHandlerForCrashExit);
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 160afe9f39..9de9396628 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -539,6 +539,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1785,7 +1786,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3068,7 +3069,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3203,20 +3204,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3464,7 +3461,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3669,6 +3666,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3941,6 +3950,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5216,7 +5226,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5259,16 +5269,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5501,6 +5501,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index f5eef6fa4e..46f0198510 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -187,6 +187,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index e917dfe92d..0783692c83 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -336,6 +336,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 1c67de2ede..54ce0b97d7 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 14fa127ab1..619b2f9c71 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index b3200874ca..e3ffc63f14 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index 56c5ec4481..c691acf8cd 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 1ee9000b2b..8ab6d859bb 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -270,6 +270,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.18.2


----Next_Part(Mon_Jun__1_18_00_01_2020_089)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v34-0005-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v35 4/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index cdd586fcfb..ee3444284b 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -489,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 5480a024e0..d398ce6f03 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -319,6 +319,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -439,30 +442,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index 37be0e2bbb..063d1323ea 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	pqsignal(SIGQUIT, SignalHandlerForCrashExit);
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index b4d475bb0b..30f3fc6ba1 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -539,6 +539,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1785,7 +1786,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3068,7 +3069,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3203,20 +3204,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3464,7 +3461,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3669,6 +3666,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3941,6 +3950,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5216,7 +5226,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5259,16 +5269,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5501,6 +5501,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index f5eef6fa4e..46f0198510 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -187,6 +187,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index e917dfe92d..0783692c83 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -336,6 +336,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 1c67de2ede..54ce0b97d7 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 18bc8a7b90..cf0b463eba 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index b3200874ca..e3ffc63f14 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index 56c5ec4481..c691acf8cd 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 1ee9000b2b..8ab6d859bb 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -270,6 +270,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.18.2


----Next_Part(Mon_Jun__8_17_32_04_2020_489)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v35-0005-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v45 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index db0cfaa360..aabf9d73eb 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 0786fcf103..430d438303 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -354,6 +354,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Fri_Jan__8_10_24_34_2021_185)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v45-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v46 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index c87ffc6549..a1e51c5b99 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 0786fcf103..430d438303 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -354,6 +354,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Thu_Jan_14_15_14_25_2021_903)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
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 filename="v46-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v47 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index c87ffc6549..a1e51c5b99 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 683ab64f76..6cdaf3753d 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -355,6 +355,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Thu_Jan_21_12_03_48_2021_284)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v47-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v48 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..22e1cd244c 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3143,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3403,7 +3400,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,6 +3606,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3912,6 +3921,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5140,7 +5150,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5204,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5445,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..491747c113 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Fri_Mar__5_17_18_56_2021_497)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v48-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v49 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 174 +++--------------------
 src/backend/postmaster/postmaster.c      |  88 ++++++------
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 83 insertions(+), 232 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..e237cedaff 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,25 +79,17 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -105,121 +98,9 @@ static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +112,24 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..d9f8d82650 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3126,6 +3127,18 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  We treat it the same way to WAL receiver.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			continue;
+		}
+
 		/*
 		 * Was it the autovacuum launcher?	Normal exit can be ignored; we'll
 		 * start a new one at the next iteration of the postmaster's main
@@ -3141,24 +3154,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3403,7 +3398,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3604,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3904,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -4989,6 +4982,19 @@ SubPostmasterMain(int argc, char *argv[])
 
 		AuxiliaryProcessMain(argc - 2, argv + 2);	/* does not return */
 	}
+	if (strcmp(argv[1], "--forkarch") == 0)
+	{
+		/* Restore basic shared memory pointers */
+		InitShmemAccess(UsedShmemSegAddr);
+
+		/* Need a PGPROC to run CreateSharedMemoryAndSemaphores */
+		InitAuxiliaryProcess();
+
+		/* Attach process to shared data structures */
+		CreateSharedMemoryAndSemaphores();
+
+		PgArchiverMain(); /* does not return */
+	}
 	if (strcmp(argv[1], "--forkavlauncher") == 0)
 	{
 		/* Restore basic shared memory pointers */
@@ -5037,12 +5043,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5140,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5194,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5435,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d73890b228 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,8 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Tue_Mar__9_16_53_11_2021_575)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v49-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v50 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 174 +++--------------------
 src/backend/postmaster/postmaster.c      |  88 ++++++------
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 83 insertions(+), 232 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..e237cedaff 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,25 +79,17 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -105,121 +98,9 @@ static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +112,24 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..d9f8d82650 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3126,6 +3127,18 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  We treat it the same way to WAL receiver.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			continue;
+		}
+
 		/*
 		 * Was it the autovacuum launcher?	Normal exit can be ignored; we'll
 		 * start a new one at the next iteration of the postmaster's main
@@ -3141,24 +3154,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3403,7 +3398,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3604,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3904,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -4989,6 +4982,19 @@ SubPostmasterMain(int argc, char *argv[])
 
 		AuxiliaryProcessMain(argc - 2, argv + 2);	/* does not return */
 	}
+	if (strcmp(argv[1], "--forkarch") == 0)
+	{
+		/* Restore basic shared memory pointers */
+		InitShmemAccess(UsedShmemSegAddr);
+
+		/* Need a PGPROC to run CreateSharedMemoryAndSemaphores */
+		InitAuxiliaryProcess();
+
+		/* Attach process to shared data structures */
+		CreateSharedMemoryAndSemaphores();
+
+		PgArchiverMain(); /* does not return */
+	}
 	if (strcmp(argv[1], "--forkavlauncher") == 0)
 	{
 		/* Restore basic shared memory pointers */
@@ -5037,12 +5043,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5140,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5194,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5435,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d73890b228 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,8 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Tue_Mar__9_18_29_34_2021_806)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v50-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v51 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 194 ++++-------------------
 src/backend/postmaster/postmaster.c      |  83 +++++-----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 94 insertions(+), 236 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..c219780c60 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,13 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,148 +75,29 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +109,27 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +602,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ *  exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	ProcGlobal->archiverLatch = NULL;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..fd509869aa 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3141,24 +3142,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3175,6 +3158,26 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving of remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
+		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			if (PgArchStartupAllowed())
+				PgArchPID = StartArchiver();
+			continue;
+		}
+
 		/* Was it the system logger?  If so, try to start a new one */
 		if (pid == SysLoggerPID)
 		{
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d71700a565 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -350,6 +350,8 @@ typedef struct PROC_HDR
 	Latch	   *walwriterLatch;
 	/* Checkpointer process's latch */
 	Latch	   *checkpointerLatch;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 	/* Current shared estimate of appropriate spins_per_delay value */
 	int			spins_per_delay;
 	/* The proc of the Startup process, since not in ProcArray */
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Wed_Mar_10_12_10_39_2021_432)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v51-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v52 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 224 ++++++++---------------
 src/backend/postmaster/postmaster.c      |  83 ++++-----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  13 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 9 files changed, 139 insertions(+), 222 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..2558bcfb08 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,13 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +493,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..c399e6c267 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,68 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	Latch	*latch;		/* latch to wake the archiver up */
+	slock_t  mutex;		/* locks this struct */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size	size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
+	return size;
+}
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool	found;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver ", PgArchShmemSize(), &found);
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
+	if (!found)
 	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
+		SpinLockInit(&PgArch->mutex);
+		PgArch->latch = NULL;
 	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
 }
-#endif							/* EXEC_BACKEND */
-
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +144,48 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = MyLatch;
+	SpinLockRelease(&PgArch->mutex);
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	Latch	*latch;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
+	SpinLockAcquire(&PgArch->mutex);
+	latch = PgArch->latch;
+	SpinLockRelease(&PgArch->mutex);
 
-	errno = save_errno;
+	if (latch)
+		SetLatch(latch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +210,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +248,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +270,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +656,17 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ *  exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = NULL;
+	SpinLockRelease(&PgArch->mutex);
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..34c8551288 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3141,24 +3142,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3175,6 +3158,26 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
+		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			if (PgArchStartupAllowed())
+				PgArchPID = StartArchiver();
+			continue;
+		}
+
 		/* Was it the system logger?  If so, try to start a new one */
 		if (pid == SysLoggerPID)
 		{
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..d053bf1564 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,9 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Wed_Mar_10_17_51_37_2021_192)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v52-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v45 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index db0cfaa360..aabf9d73eb 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 0786fcf103..430d438303 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -354,6 +354,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Fri_Jan__8_10_24_34_2021_185)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v45-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v46 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index c87ffc6549..a1e51c5b99 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 0786fcf103..430d438303 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -354,6 +354,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Thu_Jan_14_15_14_25_2021_903)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v46-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v47 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index c87ffc6549..a1e51c5b99 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 683ab64f76..6cdaf3753d 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -355,6 +355,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Thu_Jan_21_12_03_48_2021_284)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v47-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v48 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..22e1cd244c 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3143,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3403,7 +3400,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,6 +3606,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3912,6 +3921,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5140,7 +5150,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5204,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5445,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..491747c113 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Fri_Mar__5_17_18_56_2021_497)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v48-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v49 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 174 +++--------------------
 src/backend/postmaster/postmaster.c      |  88 ++++++------
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 83 insertions(+), 232 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..e237cedaff 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,25 +79,17 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -105,121 +98,9 @@ static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +112,24 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..d9f8d82650 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3126,6 +3127,18 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  We treat it the same way to WAL receiver.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			continue;
+		}
+
 		/*
 		 * Was it the autovacuum launcher?	Normal exit can be ignored; we'll
 		 * start a new one at the next iteration of the postmaster's main
@@ -3141,24 +3154,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3403,7 +3398,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3604,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3904,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -4989,6 +4982,19 @@ SubPostmasterMain(int argc, char *argv[])
 
 		AuxiliaryProcessMain(argc - 2, argv + 2);	/* does not return */
 	}
+	if (strcmp(argv[1], "--forkarch") == 0)
+	{
+		/* Restore basic shared memory pointers */
+		InitShmemAccess(UsedShmemSegAddr);
+
+		/* Need a PGPROC to run CreateSharedMemoryAndSemaphores */
+		InitAuxiliaryProcess();
+
+		/* Attach process to shared data structures */
+		CreateSharedMemoryAndSemaphores();
+
+		PgArchiverMain(); /* does not return */
+	}
 	if (strcmp(argv[1], "--forkavlauncher") == 0)
 	{
 		/* Restore basic shared memory pointers */
@@ -5037,12 +5043,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5140,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5194,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5435,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d73890b228 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,8 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Tue_Mar__9_16_53_11_2021_575)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v49-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v50 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 174 +++--------------------
 src/backend/postmaster/postmaster.c      |  88 ++++++------
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 83 insertions(+), 232 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..e237cedaff 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,25 +79,17 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -105,121 +98,9 @@ static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +112,24 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..d9f8d82650 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3126,6 +3127,18 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  We treat it the same way to WAL receiver.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			continue;
+		}
+
 		/*
 		 * Was it the autovacuum launcher?	Normal exit can be ignored; we'll
 		 * start a new one at the next iteration of the postmaster's main
@@ -3141,24 +3154,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3403,7 +3398,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3604,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3904,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -4989,6 +4982,19 @@ SubPostmasterMain(int argc, char *argv[])
 
 		AuxiliaryProcessMain(argc - 2, argv + 2);	/* does not return */
 	}
+	if (strcmp(argv[1], "--forkarch") == 0)
+	{
+		/* Restore basic shared memory pointers */
+		InitShmemAccess(UsedShmemSegAddr);
+
+		/* Need a PGPROC to run CreateSharedMemoryAndSemaphores */
+		InitAuxiliaryProcess();
+
+		/* Attach process to shared data structures */
+		CreateSharedMemoryAndSemaphores();
+
+		PgArchiverMain(); /* does not return */
+	}
 	if (strcmp(argv[1], "--forkavlauncher") == 0)
 	{
 		/* Restore basic shared memory pointers */
@@ -5037,12 +5043,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5140,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5194,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5435,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d73890b228 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,8 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Tue_Mar__9_18_29_34_2021_806)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v50-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v51 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 194 ++++-------------------
 src/backend/postmaster/postmaster.c      |  83 +++++-----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 94 insertions(+), 236 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..c219780c60 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,13 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,148 +75,29 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +109,27 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +602,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ *  exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	ProcGlobal->archiverLatch = NULL;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..fd509869aa 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3141,24 +3142,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3175,6 +3158,26 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving of remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
+		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			if (PgArchStartupAllowed())
+				PgArchPID = StartArchiver();
+			continue;
+		}
+
 		/* Was it the system logger?  If so, try to start a new one */
 		if (pid == SysLoggerPID)
 		{
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d71700a565 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -350,6 +350,8 @@ typedef struct PROC_HDR
 	Latch	   *walwriterLatch;
 	/* Checkpointer process's latch */
 	Latch	   *checkpointerLatch;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 	/* Current shared estimate of appropriate spins_per_delay value */
 	int			spins_per_delay;
 	/* The proc of the Startup process, since not in ProcArray */
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Wed_Mar_10_12_10_39_2021_432)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v51-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v52 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 224 ++++++++---------------
 src/backend/postmaster/postmaster.c      |  83 ++++-----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  13 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 9 files changed, 139 insertions(+), 222 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..2558bcfb08 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,13 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +493,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..c399e6c267 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,68 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	Latch	*latch;		/* latch to wake the archiver up */
+	slock_t  mutex;		/* locks this struct */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size	size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
+	return size;
+}
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool	found;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver ", PgArchShmemSize(), &found);
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
+	if (!found)
 	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
+		SpinLockInit(&PgArch->mutex);
+		PgArch->latch = NULL;
 	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
 }
-#endif							/* EXEC_BACKEND */
-
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +144,48 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = MyLatch;
+	SpinLockRelease(&PgArch->mutex);
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	Latch	*latch;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
+	SpinLockAcquire(&PgArch->mutex);
+	latch = PgArch->latch;
+	SpinLockRelease(&PgArch->mutex);
 
-	errno = save_errno;
+	if (latch)
+		SetLatch(latch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +210,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +248,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +270,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +656,17 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ *  exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = NULL;
+	SpinLockRelease(&PgArch->mutex);
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..34c8551288 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3141,24 +3142,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3175,6 +3158,26 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
+		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			if (PgArchStartupAllowed())
+				PgArchPID = StartArchiver();
+			continue;
+		}
+
 		/* Was it the system logger?  If so, try to start a new one */
 		if (pid == SysLoggerPID)
 		{
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..d053bf1564 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,9 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Wed_Mar_10_17_51_37_2021_192)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v52-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v45 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index db0cfaa360..aabf9d73eb 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 0786fcf103..430d438303 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -354,6 +354,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Fri_Jan__8_10_24_34_2021_185)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v45-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v47 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index c87ffc6549..a1e51c5b99 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 683ab64f76..6cdaf3753d 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -355,6 +355,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Thu_Jan_21_12_03_48_2021_284)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v47-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v48 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..22e1cd244c 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3143,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3403,7 +3400,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,6 +3606,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3912,6 +3921,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5140,7 +5150,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5204,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5445,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..491747c113 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Fri_Mar__5_17_18_56_2021_497)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v48-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v49 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 174 +++--------------------
 src/backend/postmaster/postmaster.c      |  88 ++++++------
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 83 insertions(+), 232 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..e237cedaff 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,25 +79,17 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -105,121 +98,9 @@ static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +112,24 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..d9f8d82650 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3126,6 +3127,18 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  We treat it the same way to WAL receiver.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			continue;
+		}
+
 		/*
 		 * Was it the autovacuum launcher?	Normal exit can be ignored; we'll
 		 * start a new one at the next iteration of the postmaster's main
@@ -3141,24 +3154,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3403,7 +3398,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3604,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3904,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -4989,6 +4982,19 @@ SubPostmasterMain(int argc, char *argv[])
 
 		AuxiliaryProcessMain(argc - 2, argv + 2);	/* does not return */
 	}
+	if (strcmp(argv[1], "--forkarch") == 0)
+	{
+		/* Restore basic shared memory pointers */
+		InitShmemAccess(UsedShmemSegAddr);
+
+		/* Need a PGPROC to run CreateSharedMemoryAndSemaphores */
+		InitAuxiliaryProcess();
+
+		/* Attach process to shared data structures */
+		CreateSharedMemoryAndSemaphores();
+
+		PgArchiverMain(); /* does not return */
+	}
 	if (strcmp(argv[1], "--forkavlauncher") == 0)
 	{
 		/* Restore basic shared memory pointers */
@@ -5037,12 +5043,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5140,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5194,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5435,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d73890b228 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,8 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Tue_Mar__9_16_53_11_2021_575)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v49-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v50 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 174 +++--------------------
 src/backend/postmaster/postmaster.c      |  88 ++++++------
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 83 insertions(+), 232 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..e237cedaff 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,25 +79,17 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -105,121 +98,9 @@ static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +112,24 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..d9f8d82650 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3126,6 +3127,18 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  We treat it the same way to WAL receiver.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			continue;
+		}
+
 		/*
 		 * Was it the autovacuum launcher?	Normal exit can be ignored; we'll
 		 * start a new one at the next iteration of the postmaster's main
@@ -3141,24 +3154,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3403,7 +3398,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3604,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3904,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -4989,6 +4982,19 @@ SubPostmasterMain(int argc, char *argv[])
 
 		AuxiliaryProcessMain(argc - 2, argv + 2);	/* does not return */
 	}
+	if (strcmp(argv[1], "--forkarch") == 0)
+	{
+		/* Restore basic shared memory pointers */
+		InitShmemAccess(UsedShmemSegAddr);
+
+		/* Need a PGPROC to run CreateSharedMemoryAndSemaphores */
+		InitAuxiliaryProcess();
+
+		/* Attach process to shared data structures */
+		CreateSharedMemoryAndSemaphores();
+
+		PgArchiverMain(); /* does not return */
+	}
 	if (strcmp(argv[1], "--forkavlauncher") == 0)
 	{
 		/* Restore basic shared memory pointers */
@@ -5037,12 +5043,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5140,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5194,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5435,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d73890b228 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,8 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Tue_Mar__9_18_29_34_2021_806)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v50-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v51 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 194 ++++-------------------
 src/backend/postmaster/postmaster.c      |  83 +++++-----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 94 insertions(+), 236 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..c219780c60 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,13 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,148 +75,29 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +109,27 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +602,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ *  exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	ProcGlobal->archiverLatch = NULL;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..fd509869aa 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3141,24 +3142,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3175,6 +3158,26 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving of remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
+		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			if (PgArchStartupAllowed())
+				PgArchPID = StartArchiver();
+			continue;
+		}
+
 		/* Was it the system logger?  If so, try to start a new one */
 		if (pid == SysLoggerPID)
 		{
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d71700a565 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -350,6 +350,8 @@ typedef struct PROC_HDR
 	Latch	   *walwriterLatch;
 	/* Checkpointer process's latch */
 	Latch	   *checkpointerLatch;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 	/* Current shared estimate of appropriate spins_per_delay value */
 	int			spins_per_delay;
 	/* The proc of the Startup process, since not in ProcArray */
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Wed_Mar_10_12_10_39_2021_432)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v51-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v52 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 224 ++++++++---------------
 src/backend/postmaster/postmaster.c      |  83 ++++-----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  13 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 9 files changed, 139 insertions(+), 222 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..2558bcfb08 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,13 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +493,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..c399e6c267 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,68 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	Latch	*latch;		/* latch to wake the archiver up */
+	slock_t  mutex;		/* locks this struct */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size	size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
+	return size;
+}
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool	found;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver ", PgArchShmemSize(), &found);
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
+	if (!found)
 	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
+		SpinLockInit(&PgArch->mutex);
+		PgArch->latch = NULL;
 	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
 }
-#endif							/* EXEC_BACKEND */
-
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +144,48 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = MyLatch;
+	SpinLockRelease(&PgArch->mutex);
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	Latch	*latch;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
+	SpinLockAcquire(&PgArch->mutex);
+	latch = PgArch->latch;
+	SpinLockRelease(&PgArch->mutex);
 
-	errno = save_errno;
+	if (latch)
+		SetLatch(latch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +210,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +248,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +270,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +656,17 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ *  exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = NULL;
+	SpinLockRelease(&PgArch->mutex);
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..34c8551288 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3141,24 +3142,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3175,6 +3158,26 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
+		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			if (PgArchStartupAllowed())
+				PgArchPID = StartArchiver();
+			continue;
+		}
+
 		/* Was it the system logger?  If so, try to start a new one */
 		if (pid == SysLoggerPID)
 		{
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..d053bf1564 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,9 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Wed_Mar_10_17_51_37_2021_192)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v52-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v45 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index db0cfaa360..aabf9d73eb 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 0786fcf103..430d438303 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -354,6 +354,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Fri_Jan__8_10_24_34_2021_185)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v45-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v46 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index c87ffc6549..a1e51c5b99 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 0786fcf103..430d438303 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -354,6 +354,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Thu_Jan_14_15_14_25_2021_903)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v46-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v47 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index c87ffc6549..a1e51c5b99 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 683ab64f76..6cdaf3753d 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -355,6 +355,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Thu_Jan_21_12_03_48_2021_284)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v47-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v48 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..22e1cd244c 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3143,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3403,7 +3400,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,6 +3606,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3912,6 +3921,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5140,7 +5150,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5204,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5445,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..491747c113 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Fri_Mar__5_17_18_56_2021_497)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v48-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v49 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 174 +++--------------------
 src/backend/postmaster/postmaster.c      |  88 ++++++------
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 83 insertions(+), 232 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..e237cedaff 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,25 +79,17 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -105,121 +98,9 @@ static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +112,24 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..d9f8d82650 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3126,6 +3127,18 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  We treat it the same way to WAL receiver.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			continue;
+		}
+
 		/*
 		 * Was it the autovacuum launcher?	Normal exit can be ignored; we'll
 		 * start a new one at the next iteration of the postmaster's main
@@ -3141,24 +3154,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3403,7 +3398,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3604,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3904,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -4989,6 +4982,19 @@ SubPostmasterMain(int argc, char *argv[])
 
 		AuxiliaryProcessMain(argc - 2, argv + 2);	/* does not return */
 	}
+	if (strcmp(argv[1], "--forkarch") == 0)
+	{
+		/* Restore basic shared memory pointers */
+		InitShmemAccess(UsedShmemSegAddr);
+
+		/* Need a PGPROC to run CreateSharedMemoryAndSemaphores */
+		InitAuxiliaryProcess();
+
+		/* Attach process to shared data structures */
+		CreateSharedMemoryAndSemaphores();
+
+		PgArchiverMain(); /* does not return */
+	}
 	if (strcmp(argv[1], "--forkavlauncher") == 0)
 	{
 		/* Restore basic shared memory pointers */
@@ -5037,12 +5043,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5140,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5194,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5435,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d73890b228 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,8 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Tue_Mar__9_16_53_11_2021_575)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v49-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v50 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 174 +++--------------------
 src/backend/postmaster/postmaster.c      |  88 ++++++------
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 83 insertions(+), 232 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..e237cedaff 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,25 +79,17 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -105,121 +98,9 @@ static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +112,24 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..d9f8d82650 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3126,6 +3127,18 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  We treat it the same way to WAL receiver.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			continue;
+		}
+
 		/*
 		 * Was it the autovacuum launcher?	Normal exit can be ignored; we'll
 		 * start a new one at the next iteration of the postmaster's main
@@ -3141,24 +3154,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3403,7 +3398,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3604,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3904,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -4989,6 +4982,19 @@ SubPostmasterMain(int argc, char *argv[])
 
 		AuxiliaryProcessMain(argc - 2, argv + 2);	/* does not return */
 	}
+	if (strcmp(argv[1], "--forkarch") == 0)
+	{
+		/* Restore basic shared memory pointers */
+		InitShmemAccess(UsedShmemSegAddr);
+
+		/* Need a PGPROC to run CreateSharedMemoryAndSemaphores */
+		InitAuxiliaryProcess();
+
+		/* Attach process to shared data structures */
+		CreateSharedMemoryAndSemaphores();
+
+		PgArchiverMain(); /* does not return */
+	}
 	if (strcmp(argv[1], "--forkavlauncher") == 0)
 	{
 		/* Restore basic shared memory pointers */
@@ -5037,12 +5043,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5140,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5194,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5435,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d73890b228 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,8 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Tue_Mar__9_18_29_34_2021_806)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v50-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v51 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 194 ++++-------------------
 src/backend/postmaster/postmaster.c      |  83 +++++-----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 94 insertions(+), 236 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..c219780c60 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,13 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,148 +75,29 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +109,27 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +602,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ *  exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	ProcGlobal->archiverLatch = NULL;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..fd509869aa 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3141,24 +3142,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3175,6 +3158,26 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving of remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
+		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			if (PgArchStartupAllowed())
+				PgArchPID = StartArchiver();
+			continue;
+		}
+
 		/* Was it the system logger?  If so, try to start a new one */
 		if (pid == SysLoggerPID)
 		{
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d71700a565 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -350,6 +350,8 @@ typedef struct PROC_HDR
 	Latch	   *walwriterLatch;
 	/* Checkpointer process's latch */
 	Latch	   *checkpointerLatch;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 	/* Current shared estimate of appropriate spins_per_delay value */
 	int			spins_per_delay;
 	/* The proc of the Startup process, since not in ProcArray */
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Wed_Mar_10_12_10_39_2021_432)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v51-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v52 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 224 ++++++++---------------
 src/backend/postmaster/postmaster.c      |  83 ++++-----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  13 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 9 files changed, 139 insertions(+), 222 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..2558bcfb08 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,13 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +493,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..c399e6c267 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,68 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	Latch	*latch;		/* latch to wake the archiver up */
+	slock_t  mutex;		/* locks this struct */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size	size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
+	return size;
+}
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool	found;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver ", PgArchShmemSize(), &found);
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
+	if (!found)
 	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
+		SpinLockInit(&PgArch->mutex);
+		PgArch->latch = NULL;
 	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
 }
-#endif							/* EXEC_BACKEND */
-
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +144,48 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = MyLatch;
+	SpinLockRelease(&PgArch->mutex);
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	Latch	*latch;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
+	SpinLockAcquire(&PgArch->mutex);
+	latch = PgArch->latch;
+	SpinLockRelease(&PgArch->mutex);
 
-	errno = save_errno;
+	if (latch)
+		SetLatch(latch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +210,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +248,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +270,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +656,17 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ *  exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = NULL;
+	SpinLockRelease(&PgArch->mutex);
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..34c8551288 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3141,24 +3142,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3175,6 +3158,26 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
+		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			if (PgArchStartupAllowed())
+				PgArchPID = StartArchiver();
+			continue;
+		}
+
 		/* Was it the system logger?  If so, try to start a new one */
 		if (pid == SysLoggerPID)
 		{
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..d053bf1564 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,9 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Wed_Mar_10_17_51_37_2021_192)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v52-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v45 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index db0cfaa360..aabf9d73eb 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 0786fcf103..430d438303 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -354,6 +354,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Fri_Jan__8_10_24_34_2021_185)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v45-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v46 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index c87ffc6549..a1e51c5b99 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 0786fcf103..430d438303 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -354,6 +354,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Thu_Jan_14_15_14_25_2021_903)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v46-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v47 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index c87ffc6549..a1e51c5b99 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 683ab64f76..6cdaf3753d 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -355,6 +355,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Thu_Jan_21_12_03_48_2021_284)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v47-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v48 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..22e1cd244c 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3143,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3403,7 +3400,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,6 +3606,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3912,6 +3921,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5140,7 +5150,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5204,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5445,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..491747c113 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Fri_Mar__5_17_18_56_2021_497)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v48-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v49 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 174 +++--------------------
 src/backend/postmaster/postmaster.c      |  88 ++++++------
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 83 insertions(+), 232 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..e237cedaff 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,25 +79,17 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -105,121 +98,9 @@ static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +112,24 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..d9f8d82650 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3126,6 +3127,18 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  We treat it the same way to WAL receiver.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			continue;
+		}
+
 		/*
 		 * Was it the autovacuum launcher?	Normal exit can be ignored; we'll
 		 * start a new one at the next iteration of the postmaster's main
@@ -3141,24 +3154,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3403,7 +3398,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3604,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3904,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -4989,6 +4982,19 @@ SubPostmasterMain(int argc, char *argv[])
 
 		AuxiliaryProcessMain(argc - 2, argv + 2);	/* does not return */
 	}
+	if (strcmp(argv[1], "--forkarch") == 0)
+	{
+		/* Restore basic shared memory pointers */
+		InitShmemAccess(UsedShmemSegAddr);
+
+		/* Need a PGPROC to run CreateSharedMemoryAndSemaphores */
+		InitAuxiliaryProcess();
+
+		/* Attach process to shared data structures */
+		CreateSharedMemoryAndSemaphores();
+
+		PgArchiverMain(); /* does not return */
+	}
 	if (strcmp(argv[1], "--forkavlauncher") == 0)
 	{
 		/* Restore basic shared memory pointers */
@@ -5037,12 +5043,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5140,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5194,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5435,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d73890b228 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,8 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Tue_Mar__9_16_53_11_2021_575)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v49-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v50 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 174 +++--------------------
 src/backend/postmaster/postmaster.c      |  88 ++++++------
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 83 insertions(+), 232 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..e237cedaff 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,25 +79,17 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -105,121 +98,9 @@ static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +112,24 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..d9f8d82650 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3126,6 +3127,18 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  We treat it the same way to WAL receiver.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			continue;
+		}
+
 		/*
 		 * Was it the autovacuum launcher?	Normal exit can be ignored; we'll
 		 * start a new one at the next iteration of the postmaster's main
@@ -3141,24 +3154,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3403,7 +3398,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3604,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3904,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -4989,6 +4982,19 @@ SubPostmasterMain(int argc, char *argv[])
 
 		AuxiliaryProcessMain(argc - 2, argv + 2);	/* does not return */
 	}
+	if (strcmp(argv[1], "--forkarch") == 0)
+	{
+		/* Restore basic shared memory pointers */
+		InitShmemAccess(UsedShmemSegAddr);
+
+		/* Need a PGPROC to run CreateSharedMemoryAndSemaphores */
+		InitAuxiliaryProcess();
+
+		/* Attach process to shared data structures */
+		CreateSharedMemoryAndSemaphores();
+
+		PgArchiverMain(); /* does not return */
+	}
 	if (strcmp(argv[1], "--forkavlauncher") == 0)
 	{
 		/* Restore basic shared memory pointers */
@@ -5037,12 +5043,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5140,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5194,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5435,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d73890b228 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,8 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Tue_Mar__9_18_29_34_2021_806)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v50-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v51 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 194 ++++-------------------
 src/backend/postmaster/postmaster.c      |  83 +++++-----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 94 insertions(+), 236 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..c219780c60 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,13 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,148 +75,29 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +109,27 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +602,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ *  exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	ProcGlobal->archiverLatch = NULL;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..fd509869aa 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3141,24 +3142,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3175,6 +3158,26 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving of remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
+		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			if (PgArchStartupAllowed())
+				PgArchPID = StartArchiver();
+			continue;
+		}
+
 		/* Was it the system logger?  If so, try to start a new one */
 		if (pid == SysLoggerPID)
 		{
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d71700a565 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -350,6 +350,8 @@ typedef struct PROC_HDR
 	Latch	   *walwriterLatch;
 	/* Checkpointer process's latch */
 	Latch	   *checkpointerLatch;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 	/* Current shared estimate of appropriate spins_per_delay value */
 	int			spins_per_delay;
 	/* The proc of the Startup process, since not in ProcArray */
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Wed_Mar_10_12_10_39_2021_432)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v51-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v52 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 224 ++++++++---------------
 src/backend/postmaster/postmaster.c      |  83 ++++-----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  13 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 9 files changed, 139 insertions(+), 222 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..2558bcfb08 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,13 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +493,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..c399e6c267 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,68 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	Latch	*latch;		/* latch to wake the archiver up */
+	slock_t  mutex;		/* locks this struct */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size	size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
+	return size;
+}
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool	found;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver ", PgArchShmemSize(), &found);
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
+	if (!found)
 	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
+		SpinLockInit(&PgArch->mutex);
+		PgArch->latch = NULL;
 	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
 }
-#endif							/* EXEC_BACKEND */
-
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +144,48 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = MyLatch;
+	SpinLockRelease(&PgArch->mutex);
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	Latch	*latch;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
+	SpinLockAcquire(&PgArch->mutex);
+	latch = PgArch->latch;
+	SpinLockRelease(&PgArch->mutex);
 
-	errno = save_errno;
+	if (latch)
+		SetLatch(latch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +210,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +248,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +270,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +656,17 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ *  exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = NULL;
+	SpinLockRelease(&PgArch->mutex);
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..34c8551288 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3141,24 +3142,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3175,6 +3158,26 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
+		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			if (PgArchStartupAllowed())
+				PgArchPID = StartArchiver();
+			continue;
+		}
+
 		/* Was it the system logger?  If so, try to start a new one */
 		if (pid == SysLoggerPID)
 		{
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..d053bf1564 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,9 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Wed_Mar_10_17_51_37_2021_192)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v52-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v45 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index db0cfaa360..aabf9d73eb 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 0786fcf103..430d438303 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -354,6 +354,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Fri_Jan__8_10_24_34_2021_185)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v45-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v46 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index c87ffc6549..a1e51c5b99 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 0786fcf103..430d438303 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -354,6 +354,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Thu_Jan_14_15_14_25_2021_903)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v46-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v47 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index c87ffc6549..a1e51c5b99 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 683ab64f76..6cdaf3753d 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -355,6 +355,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Thu_Jan_21_12_03_48_2021_284)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v47-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v48 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..22e1cd244c 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3143,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3403,7 +3400,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,6 +3606,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3912,6 +3921,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5140,7 +5150,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5204,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5445,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..491747c113 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Fri_Mar__5_17_18_56_2021_497)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v48-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v49 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 174 +++--------------------
 src/backend/postmaster/postmaster.c      |  88 ++++++------
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 83 insertions(+), 232 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..e237cedaff 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,25 +79,17 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -105,121 +98,9 @@ static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +112,24 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..d9f8d82650 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3126,6 +3127,18 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  We treat it the same way to WAL receiver.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			continue;
+		}
+
 		/*
 		 * Was it the autovacuum launcher?	Normal exit can be ignored; we'll
 		 * start a new one at the next iteration of the postmaster's main
@@ -3141,24 +3154,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3403,7 +3398,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3604,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3904,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -4989,6 +4982,19 @@ SubPostmasterMain(int argc, char *argv[])
 
 		AuxiliaryProcessMain(argc - 2, argv + 2);	/* does not return */
 	}
+	if (strcmp(argv[1], "--forkarch") == 0)
+	{
+		/* Restore basic shared memory pointers */
+		InitShmemAccess(UsedShmemSegAddr);
+
+		/* Need a PGPROC to run CreateSharedMemoryAndSemaphores */
+		InitAuxiliaryProcess();
+
+		/* Attach process to shared data structures */
+		CreateSharedMemoryAndSemaphores();
+
+		PgArchiverMain(); /* does not return */
+	}
 	if (strcmp(argv[1], "--forkavlauncher") == 0)
 	{
 		/* Restore basic shared memory pointers */
@@ -5037,12 +5043,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5140,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5194,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5435,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d73890b228 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,8 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Tue_Mar__9_16_53_11_2021_575)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v49-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v50 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 174 +++--------------------
 src/backend/postmaster/postmaster.c      |  88 ++++++------
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 83 insertions(+), 232 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..e237cedaff 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,25 +79,17 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -105,121 +98,9 @@ static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +112,24 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..d9f8d82650 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3126,6 +3127,18 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  We treat it the same way to WAL receiver.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			continue;
+		}
+
 		/*
 		 * Was it the autovacuum launcher?	Normal exit can be ignored; we'll
 		 * start a new one at the next iteration of the postmaster's main
@@ -3141,24 +3154,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3403,7 +3398,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3604,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3904,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -4989,6 +4982,19 @@ SubPostmasterMain(int argc, char *argv[])
 
 		AuxiliaryProcessMain(argc - 2, argv + 2);	/* does not return */
 	}
+	if (strcmp(argv[1], "--forkarch") == 0)
+	{
+		/* Restore basic shared memory pointers */
+		InitShmemAccess(UsedShmemSegAddr);
+
+		/* Need a PGPROC to run CreateSharedMemoryAndSemaphores */
+		InitAuxiliaryProcess();
+
+		/* Attach process to shared data structures */
+		CreateSharedMemoryAndSemaphores();
+
+		PgArchiverMain(); /* does not return */
+	}
 	if (strcmp(argv[1], "--forkavlauncher") == 0)
 	{
 		/* Restore basic shared memory pointers */
@@ -5037,12 +5043,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5140,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5194,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5435,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d73890b228 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,8 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Tue_Mar__9_18_29_34_2021_806)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v50-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v51 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 194 ++++-------------------
 src/backend/postmaster/postmaster.c      |  83 +++++-----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 94 insertions(+), 236 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..c219780c60 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,13 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,148 +75,29 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +109,27 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +602,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ *  exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	ProcGlobal->archiverLatch = NULL;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..fd509869aa 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3141,24 +3142,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3175,6 +3158,26 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving of remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
+		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			if (PgArchStartupAllowed())
+				PgArchPID = StartArchiver();
+			continue;
+		}
+
 		/* Was it the system logger?  If so, try to start a new one */
 		if (pid == SysLoggerPID)
 		{
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d71700a565 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -350,6 +350,8 @@ typedef struct PROC_HDR
 	Latch	   *walwriterLatch;
 	/* Checkpointer process's latch */
 	Latch	   *checkpointerLatch;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 	/* Current shared estimate of appropriate spins_per_delay value */
 	int			spins_per_delay;
 	/* The proc of the Startup process, since not in ProcArray */
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Wed_Mar_10_12_10_39_2021_432)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v51-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v52 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 224 ++++++++---------------
 src/backend/postmaster/postmaster.c      |  83 ++++-----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  13 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 9 files changed, 139 insertions(+), 222 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..2558bcfb08 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,13 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +493,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..c399e6c267 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,68 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	Latch	*latch;		/* latch to wake the archiver up */
+	slock_t  mutex;		/* locks this struct */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size	size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
+	return size;
+}
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool	found;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver ", PgArchShmemSize(), &found);
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
+	if (!found)
 	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
+		SpinLockInit(&PgArch->mutex);
+		PgArch->latch = NULL;
 	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
 }
-#endif							/* EXEC_BACKEND */
-
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +144,48 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = MyLatch;
+	SpinLockRelease(&PgArch->mutex);
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	Latch	*latch;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
+	SpinLockAcquire(&PgArch->mutex);
+	latch = PgArch->latch;
+	SpinLockRelease(&PgArch->mutex);
 
-	errno = save_errno;
+	if (latch)
+		SetLatch(latch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +210,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +248,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +270,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +656,17 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ *  exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = NULL;
+	SpinLockRelease(&PgArch->mutex);
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..34c8551288 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3141,24 +3142,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3175,6 +3158,26 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
+		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			if (PgArchStartupAllowed())
+				PgArchPID = StartArchiver();
+			continue;
+		}
+
 		/* Was it the system logger?  If so, try to start a new one */
 		if (pid == SysLoggerPID)
 		{
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..d053bf1564 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,9 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Wed_Mar_10_17_51_37_2021_192)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v52-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v45 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index db0cfaa360..aabf9d73eb 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 0786fcf103..430d438303 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -354,6 +354,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Fri_Jan__8_10_24_34_2021_185)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v45-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v46 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index c87ffc6549..a1e51c5b99 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 0786fcf103..430d438303 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -354,6 +354,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Thu_Jan_14_15_14_25_2021_903)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v46-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v47 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index c87ffc6549..a1e51c5b99 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 683ab64f76..6cdaf3753d 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -355,6 +355,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Thu_Jan_21_12_03_48_2021_284)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v47-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v48 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..22e1cd244c 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3143,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3403,7 +3400,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,6 +3606,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3912,6 +3921,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5140,7 +5150,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5204,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5445,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..491747c113 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Fri_Mar__5_17_18_56_2021_497)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v48-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v49 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 174 +++--------------------
 src/backend/postmaster/postmaster.c      |  88 ++++++------
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 83 insertions(+), 232 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..e237cedaff 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,25 +79,17 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -105,121 +98,9 @@ static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +112,24 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..d9f8d82650 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3126,6 +3127,18 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  We treat it the same way to WAL receiver.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			continue;
+		}
+
 		/*
 		 * Was it the autovacuum launcher?	Normal exit can be ignored; we'll
 		 * start a new one at the next iteration of the postmaster's main
@@ -3141,24 +3154,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3403,7 +3398,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3604,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3904,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -4989,6 +4982,19 @@ SubPostmasterMain(int argc, char *argv[])
 
 		AuxiliaryProcessMain(argc - 2, argv + 2);	/* does not return */
 	}
+	if (strcmp(argv[1], "--forkarch") == 0)
+	{
+		/* Restore basic shared memory pointers */
+		InitShmemAccess(UsedShmemSegAddr);
+
+		/* Need a PGPROC to run CreateSharedMemoryAndSemaphores */
+		InitAuxiliaryProcess();
+
+		/* Attach process to shared data structures */
+		CreateSharedMemoryAndSemaphores();
+
+		PgArchiverMain(); /* does not return */
+	}
 	if (strcmp(argv[1], "--forkavlauncher") == 0)
 	{
 		/* Restore basic shared memory pointers */
@@ -5037,12 +5043,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5140,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5194,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5435,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d73890b228 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,8 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Tue_Mar__9_16_53_11_2021_575)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v49-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v50 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 174 +++--------------------
 src/backend/postmaster/postmaster.c      |  88 ++++++------
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 83 insertions(+), 232 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..e237cedaff 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,25 +79,17 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -105,121 +98,9 @@ static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +112,24 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..d9f8d82650 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3126,6 +3127,18 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  We treat it the same way to WAL receiver.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			continue;
+		}
+
 		/*
 		 * Was it the autovacuum launcher?	Normal exit can be ignored; we'll
 		 * start a new one at the next iteration of the postmaster's main
@@ -3141,24 +3154,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3403,7 +3398,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3604,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3904,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -4989,6 +4982,19 @@ SubPostmasterMain(int argc, char *argv[])
 
 		AuxiliaryProcessMain(argc - 2, argv + 2);	/* does not return */
 	}
+	if (strcmp(argv[1], "--forkarch") == 0)
+	{
+		/* Restore basic shared memory pointers */
+		InitShmemAccess(UsedShmemSegAddr);
+
+		/* Need a PGPROC to run CreateSharedMemoryAndSemaphores */
+		InitAuxiliaryProcess();
+
+		/* Attach process to shared data structures */
+		CreateSharedMemoryAndSemaphores();
+
+		PgArchiverMain(); /* does not return */
+	}
 	if (strcmp(argv[1], "--forkavlauncher") == 0)
 	{
 		/* Restore basic shared memory pointers */
@@ -5037,12 +5043,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5140,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5194,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5435,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d73890b228 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,8 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Tue_Mar__9_18_29_34_2021_806)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v50-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v51 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 194 ++++-------------------
 src/backend/postmaster/postmaster.c      |  83 +++++-----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 94 insertions(+), 236 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..c219780c60 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,13 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,148 +75,29 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +109,27 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +602,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ *  exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	ProcGlobal->archiverLatch = NULL;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..fd509869aa 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3141,24 +3142,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3175,6 +3158,26 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving of remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
+		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			if (PgArchStartupAllowed())
+				PgArchPID = StartArchiver();
+			continue;
+		}
+
 		/* Was it the system logger?  If so, try to start a new one */
 		if (pid == SysLoggerPID)
 		{
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d71700a565 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -350,6 +350,8 @@ typedef struct PROC_HDR
 	Latch	   *walwriterLatch;
 	/* Checkpointer process's latch */
 	Latch	   *checkpointerLatch;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 	/* Current shared estimate of appropriate spins_per_delay value */
 	int			spins_per_delay;
 	/* The proc of the Startup process, since not in ProcArray */
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Wed_Mar_10_12_10_39_2021_432)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v51-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v52 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 224 ++++++++---------------
 src/backend/postmaster/postmaster.c      |  83 ++++-----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  13 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 9 files changed, 139 insertions(+), 222 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..2558bcfb08 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,13 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +493,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..c399e6c267 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,68 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	Latch	*latch;		/* latch to wake the archiver up */
+	slock_t  mutex;		/* locks this struct */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size	size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
+	return size;
+}
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool	found;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver ", PgArchShmemSize(), &found);
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
+	if (!found)
 	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
+		SpinLockInit(&PgArch->mutex);
+		PgArch->latch = NULL;
 	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
 }
-#endif							/* EXEC_BACKEND */
-
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +144,48 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = MyLatch;
+	SpinLockRelease(&PgArch->mutex);
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	Latch	*latch;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
+	SpinLockAcquire(&PgArch->mutex);
+	latch = PgArch->latch;
+	SpinLockRelease(&PgArch->mutex);
 
-	errno = save_errno;
+	if (latch)
+		SetLatch(latch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +210,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +248,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +270,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +656,17 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ *  exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = NULL;
+	SpinLockRelease(&PgArch->mutex);
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..34c8551288 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3141,24 +3142,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3175,6 +3158,26 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
+		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			if (PgArchStartupAllowed())
+				PgArchPID = StartArchiver();
+			continue;
+		}
+
 		/* Was it the system logger?  If so, try to start a new one */
 		if (pid == SysLoggerPID)
 		{
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..d053bf1564 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,9 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Wed_Mar_10_17_51_37_2021_192)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v52-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v48 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..22e1cd244c 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3143,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3403,7 +3400,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,6 +3606,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3912,6 +3921,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5140,7 +5150,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5204,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5445,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..491747c113 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Fri_Mar__5_17_18_56_2021_497)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v48-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v49 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 174 +++--------------------
 src/backend/postmaster/postmaster.c      |  88 ++++++------
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 83 insertions(+), 232 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..e237cedaff 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,25 +79,17 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -105,121 +98,9 @@ static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +112,24 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..d9f8d82650 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3126,6 +3127,18 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  We treat it the same way to WAL receiver.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			continue;
+		}
+
 		/*
 		 * Was it the autovacuum launcher?	Normal exit can be ignored; we'll
 		 * start a new one at the next iteration of the postmaster's main
@@ -3141,24 +3154,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3403,7 +3398,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3604,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3904,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -4989,6 +4982,19 @@ SubPostmasterMain(int argc, char *argv[])
 
 		AuxiliaryProcessMain(argc - 2, argv + 2);	/* does not return */
 	}
+	if (strcmp(argv[1], "--forkarch") == 0)
+	{
+		/* Restore basic shared memory pointers */
+		InitShmemAccess(UsedShmemSegAddr);
+
+		/* Need a PGPROC to run CreateSharedMemoryAndSemaphores */
+		InitAuxiliaryProcess();
+
+		/* Attach process to shared data structures */
+		CreateSharedMemoryAndSemaphores();
+
+		PgArchiverMain(); /* does not return */
+	}
 	if (strcmp(argv[1], "--forkavlauncher") == 0)
 	{
 		/* Restore basic shared memory pointers */
@@ -5037,12 +5043,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5140,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5194,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5435,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d73890b228 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,8 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Tue_Mar__9_16_53_11_2021_575)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v49-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v50 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 174 +++--------------------
 src/backend/postmaster/postmaster.c      |  88 ++++++------
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 83 insertions(+), 232 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..e237cedaff 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,25 +79,17 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -105,121 +98,9 @@ static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +112,24 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..d9f8d82650 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3126,6 +3127,18 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  We treat it the same way to WAL receiver.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			continue;
+		}
+
 		/*
 		 * Was it the autovacuum launcher?	Normal exit can be ignored; we'll
 		 * start a new one at the next iteration of the postmaster's main
@@ -3141,24 +3154,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3403,7 +3398,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3604,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3904,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -4989,6 +4982,19 @@ SubPostmasterMain(int argc, char *argv[])
 
 		AuxiliaryProcessMain(argc - 2, argv + 2);	/* does not return */
 	}
+	if (strcmp(argv[1], "--forkarch") == 0)
+	{
+		/* Restore basic shared memory pointers */
+		InitShmemAccess(UsedShmemSegAddr);
+
+		/* Need a PGPROC to run CreateSharedMemoryAndSemaphores */
+		InitAuxiliaryProcess();
+
+		/* Attach process to shared data structures */
+		CreateSharedMemoryAndSemaphores();
+
+		PgArchiverMain(); /* does not return */
+	}
 	if (strcmp(argv[1], "--forkavlauncher") == 0)
 	{
 		/* Restore basic shared memory pointers */
@@ -5037,12 +5043,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5140,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5194,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5435,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d73890b228 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,8 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Tue_Mar__9_18_29_34_2021_806)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v50-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v51 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 194 ++++-------------------
 src/backend/postmaster/postmaster.c      |  83 +++++-----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 94 insertions(+), 236 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..c219780c60 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,13 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,148 +75,29 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +109,27 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +602,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ *  exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	ProcGlobal->archiverLatch = NULL;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..fd509869aa 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3141,24 +3142,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3175,6 +3158,26 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving of remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
+		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			if (PgArchStartupAllowed())
+				PgArchPID = StartArchiver();
+			continue;
+		}
+
 		/* Was it the system logger?  If so, try to start a new one */
 		if (pid == SysLoggerPID)
 		{
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d71700a565 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -350,6 +350,8 @@ typedef struct PROC_HDR
 	Latch	   *walwriterLatch;
 	/* Checkpointer process's latch */
 	Latch	   *checkpointerLatch;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 	/* Current shared estimate of appropriate spins_per_delay value */
 	int			spins_per_delay;
 	/* The proc of the Startup process, since not in ProcArray */
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Wed_Mar_10_12_10_39_2021_432)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v51-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v52 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 224 ++++++++---------------
 src/backend/postmaster/postmaster.c      |  83 ++++-----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  13 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 9 files changed, 139 insertions(+), 222 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..2558bcfb08 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,13 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +493,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..c399e6c267 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,68 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	Latch	*latch;		/* latch to wake the archiver up */
+	slock_t  mutex;		/* locks this struct */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size	size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
+	return size;
+}
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool	found;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver ", PgArchShmemSize(), &found);
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
+	if (!found)
 	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
+		SpinLockInit(&PgArch->mutex);
+		PgArch->latch = NULL;
 	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
 }
-#endif							/* EXEC_BACKEND */
-
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +144,48 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = MyLatch;
+	SpinLockRelease(&PgArch->mutex);
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	Latch	*latch;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
+	SpinLockAcquire(&PgArch->mutex);
+	latch = PgArch->latch;
+	SpinLockRelease(&PgArch->mutex);
 
-	errno = save_errno;
+	if (latch)
+		SetLatch(latch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +210,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +248,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +270,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +656,17 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ *  exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = NULL;
+	SpinLockRelease(&PgArch->mutex);
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..34c8551288 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3141,24 +3142,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3175,6 +3158,26 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
+		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			if (PgArchStartupAllowed())
+				PgArchPID = StartArchiver();
+			continue;
+		}
+
 		/* Was it the system logger?  If so, try to start a new one */
 		if (pid == SysLoggerPID)
 		{
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..d053bf1564 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,9 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Wed_Mar_10_17_51_37_2021_192)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v52-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v45 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index db0cfaa360..aabf9d73eb 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 0786fcf103..430d438303 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -354,6 +354,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Fri_Jan__8_10_24_34_2021_185)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v45-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v46 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index c87ffc6549..a1e51c5b99 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 0786fcf103..430d438303 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -354,6 +354,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Thu_Jan_14_15_14_25_2021_903)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v46-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v47 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index c87ffc6549..a1e51c5b99 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 683ab64f76..6cdaf3753d 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -355,6 +355,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Thu_Jan_21_12_03_48_2021_284)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v47-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v48 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..22e1cd244c 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3143,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3403,7 +3400,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,6 +3606,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3912,6 +3921,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5140,7 +5150,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5204,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5445,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..491747c113 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Fri_Mar__5_17_18_56_2021_497)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v48-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v49 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 174 +++--------------------
 src/backend/postmaster/postmaster.c      |  88 ++++++------
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 83 insertions(+), 232 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..e237cedaff 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,25 +79,17 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -105,121 +98,9 @@ static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +112,24 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..d9f8d82650 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3126,6 +3127,18 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  We treat it the same way to WAL receiver.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			continue;
+		}
+
 		/*
 		 * Was it the autovacuum launcher?	Normal exit can be ignored; we'll
 		 * start a new one at the next iteration of the postmaster's main
@@ -3141,24 +3154,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3403,7 +3398,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3604,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3904,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -4989,6 +4982,19 @@ SubPostmasterMain(int argc, char *argv[])
 
 		AuxiliaryProcessMain(argc - 2, argv + 2);	/* does not return */
 	}
+	if (strcmp(argv[1], "--forkarch") == 0)
+	{
+		/* Restore basic shared memory pointers */
+		InitShmemAccess(UsedShmemSegAddr);
+
+		/* Need a PGPROC to run CreateSharedMemoryAndSemaphores */
+		InitAuxiliaryProcess();
+
+		/* Attach process to shared data structures */
+		CreateSharedMemoryAndSemaphores();
+
+		PgArchiverMain(); /* does not return */
+	}
 	if (strcmp(argv[1], "--forkavlauncher") == 0)
 	{
 		/* Restore basic shared memory pointers */
@@ -5037,12 +5043,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5140,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5194,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5435,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d73890b228 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,8 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


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Content-Transfer-Encoding: 7bit
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 filename="v49-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v50 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 174 +++--------------------
 src/backend/postmaster/postmaster.c      |  88 ++++++------
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 83 insertions(+), 232 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..e237cedaff 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,25 +79,17 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -105,121 +98,9 @@ static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +112,24 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..d9f8d82650 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3126,6 +3127,18 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  We treat it the same way to WAL receiver.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			continue;
+		}
+
 		/*
 		 * Was it the autovacuum launcher?	Normal exit can be ignored; we'll
 		 * start a new one at the next iteration of the postmaster's main
@@ -3141,24 +3154,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3403,7 +3398,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3604,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3904,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -4989,6 +4982,19 @@ SubPostmasterMain(int argc, char *argv[])
 
 		AuxiliaryProcessMain(argc - 2, argv + 2);	/* does not return */
 	}
+	if (strcmp(argv[1], "--forkarch") == 0)
+	{
+		/* Restore basic shared memory pointers */
+		InitShmemAccess(UsedShmemSegAddr);
+
+		/* Need a PGPROC to run CreateSharedMemoryAndSemaphores */
+		InitAuxiliaryProcess();
+
+		/* Attach process to shared data structures */
+		CreateSharedMemoryAndSemaphores();
+
+		PgArchiverMain(); /* does not return */
+	}
 	if (strcmp(argv[1], "--forkavlauncher") == 0)
 	{
 		/* Restore basic shared memory pointers */
@@ -5037,12 +5043,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5140,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5194,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5435,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d73890b228 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,8 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


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^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v51 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 194 ++++-------------------
 src/backend/postmaster/postmaster.c      |  83 +++++-----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 94 insertions(+), 236 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..c219780c60 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,13 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,148 +75,29 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +109,27 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +602,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ *  exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	ProcGlobal->archiverLatch = NULL;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..fd509869aa 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3141,24 +3142,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3175,6 +3158,26 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving of remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
+		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			if (PgArchStartupAllowed())
+				PgArchPID = StartArchiver();
+			continue;
+		}
+
 		/* Was it the system logger?  If so, try to start a new one */
 		if (pid == SysLoggerPID)
 		{
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d71700a565 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -350,6 +350,8 @@ typedef struct PROC_HDR
 	Latch	   *walwriterLatch;
 	/* Checkpointer process's latch */
 	Latch	   *checkpointerLatch;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 	/* Current shared estimate of appropriate spins_per_delay value */
 	int			spins_per_delay;
 	/* The proc of the Startup process, since not in ProcArray */
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Wed_Mar_10_12_10_39_2021_432)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v51-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v52 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 224 ++++++++---------------
 src/backend/postmaster/postmaster.c      |  83 ++++-----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  13 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 9 files changed, 139 insertions(+), 222 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..2558bcfb08 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,13 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +493,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..c399e6c267 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,68 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	Latch	*latch;		/* latch to wake the archiver up */
+	slock_t  mutex;		/* locks this struct */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size	size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
+	return size;
+}
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool	found;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver ", PgArchShmemSize(), &found);
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
+	if (!found)
 	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
+		SpinLockInit(&PgArch->mutex);
+		PgArch->latch = NULL;
 	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
 }
-#endif							/* EXEC_BACKEND */
-
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +144,48 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = MyLatch;
+	SpinLockRelease(&PgArch->mutex);
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	Latch	*latch;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
+	SpinLockAcquire(&PgArch->mutex);
+	latch = PgArch->latch;
+	SpinLockRelease(&PgArch->mutex);
 
-	errno = save_errno;
+	if (latch)
+		SetLatch(latch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +210,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +248,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +270,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +656,17 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ *  exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = NULL;
+	SpinLockRelease(&PgArch->mutex);
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..34c8551288 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3141,24 +3142,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3175,6 +3158,26 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
+		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			if (PgArchStartupAllowed())
+				PgArchPID = StartArchiver();
+			continue;
+		}
+
 		/* Was it the system logger?  If so, try to start a new one */
 		if (pid == SysLoggerPID)
 		{
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..d053bf1564 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,9 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Wed_Mar_10_17_51_37_2021_192)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v52-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v45 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index db0cfaa360..aabf9d73eb 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 0786fcf103..430d438303 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -354,6 +354,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Fri_Jan__8_10_24_34_2021_185)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v45-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v46 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index c87ffc6549..a1e51c5b99 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 0786fcf103..430d438303 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -354,6 +354,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Thu_Jan_14_15_14_25_2021_903)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v46-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v47 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index c87ffc6549..a1e51c5b99 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 683ab64f76..6cdaf3753d 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -355,6 +355,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Thu_Jan_21_12_03_48_2021_284)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v47-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v48 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..22e1cd244c 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3143,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3403,7 +3400,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,6 +3606,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3912,6 +3921,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5140,7 +5150,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5204,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5445,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..491747c113 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Fri_Mar__5_17_18_56_2021_497)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v48-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v49 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 174 +++--------------------
 src/backend/postmaster/postmaster.c      |  88 ++++++------
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 83 insertions(+), 232 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..e237cedaff 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,25 +79,17 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -105,121 +98,9 @@ static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +112,24 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..d9f8d82650 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3126,6 +3127,18 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  We treat it the same way to WAL receiver.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			continue;
+		}
+
 		/*
 		 * Was it the autovacuum launcher?	Normal exit can be ignored; we'll
 		 * start a new one at the next iteration of the postmaster's main
@@ -3141,24 +3154,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3403,7 +3398,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3604,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3904,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -4989,6 +4982,19 @@ SubPostmasterMain(int argc, char *argv[])
 
 		AuxiliaryProcessMain(argc - 2, argv + 2);	/* does not return */
 	}
+	if (strcmp(argv[1], "--forkarch") == 0)
+	{
+		/* Restore basic shared memory pointers */
+		InitShmemAccess(UsedShmemSegAddr);
+
+		/* Need a PGPROC to run CreateSharedMemoryAndSemaphores */
+		InitAuxiliaryProcess();
+
+		/* Attach process to shared data structures */
+		CreateSharedMemoryAndSemaphores();
+
+		PgArchiverMain(); /* does not return */
+	}
 	if (strcmp(argv[1], "--forkavlauncher") == 0)
 	{
 		/* Restore basic shared memory pointers */
@@ -5037,12 +5043,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5140,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5194,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5435,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d73890b228 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,8 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Tue_Mar__9_16_53_11_2021_575)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v49-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v50 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 174 +++--------------------
 src/backend/postmaster/postmaster.c      |  88 ++++++------
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 83 insertions(+), 232 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..e237cedaff 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,25 +79,17 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -105,121 +98,9 @@ static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +112,24 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..d9f8d82650 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3126,6 +3127,18 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  We treat it the same way to WAL receiver.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			continue;
+		}
+
 		/*
 		 * Was it the autovacuum launcher?	Normal exit can be ignored; we'll
 		 * start a new one at the next iteration of the postmaster's main
@@ -3141,24 +3154,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3403,7 +3398,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3604,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3904,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -4989,6 +4982,19 @@ SubPostmasterMain(int argc, char *argv[])
 
 		AuxiliaryProcessMain(argc - 2, argv + 2);	/* does not return */
 	}
+	if (strcmp(argv[1], "--forkarch") == 0)
+	{
+		/* Restore basic shared memory pointers */
+		InitShmemAccess(UsedShmemSegAddr);
+
+		/* Need a PGPROC to run CreateSharedMemoryAndSemaphores */
+		InitAuxiliaryProcess();
+
+		/* Attach process to shared data structures */
+		CreateSharedMemoryAndSemaphores();
+
+		PgArchiverMain(); /* does not return */
+	}
 	if (strcmp(argv[1], "--forkavlauncher") == 0)
 	{
 		/* Restore basic shared memory pointers */
@@ -5037,12 +5043,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5140,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5194,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5435,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d73890b228 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,8 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Tue_Mar__9_18_29_34_2021_806)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v50-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v51 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 194 ++++-------------------
 src/backend/postmaster/postmaster.c      |  83 +++++-----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 94 insertions(+), 236 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..c219780c60 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,13 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,148 +75,29 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +109,27 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +602,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ *  exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	ProcGlobal->archiverLatch = NULL;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..fd509869aa 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3141,24 +3142,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3175,6 +3158,26 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving of remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
+		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			if (PgArchStartupAllowed())
+				PgArchPID = StartArchiver();
+			continue;
+		}
+
 		/* Was it the system logger?  If so, try to start a new one */
 		if (pid == SysLoggerPID)
 		{
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d71700a565 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -350,6 +350,8 @@ typedef struct PROC_HDR
 	Latch	   *walwriterLatch;
 	/* Checkpointer process's latch */
 	Latch	   *checkpointerLatch;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 	/* Current shared estimate of appropriate spins_per_delay value */
 	int			spins_per_delay;
 	/* The proc of the Startup process, since not in ProcArray */
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Wed_Mar_10_12_10_39_2021_432)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v51-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v52 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 224 ++++++++---------------
 src/backend/postmaster/postmaster.c      |  83 ++++-----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  13 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 9 files changed, 139 insertions(+), 222 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..2558bcfb08 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,13 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +493,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..c399e6c267 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,68 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	Latch	*latch;		/* latch to wake the archiver up */
+	slock_t  mutex;		/* locks this struct */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size	size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
+	return size;
+}
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool	found;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver ", PgArchShmemSize(), &found);
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
+	if (!found)
 	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
+		SpinLockInit(&PgArch->mutex);
+		PgArch->latch = NULL;
 	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
 }
-#endif							/* EXEC_BACKEND */
-
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +144,48 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = MyLatch;
+	SpinLockRelease(&PgArch->mutex);
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	Latch	*latch;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
+	SpinLockAcquire(&PgArch->mutex);
+	latch = PgArch->latch;
+	SpinLockRelease(&PgArch->mutex);
 
-	errno = save_errno;
+	if (latch)
+		SetLatch(latch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +210,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +248,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +270,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +656,17 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ *  exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = NULL;
+	SpinLockRelease(&PgArch->mutex);
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..34c8551288 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3141,24 +3142,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3175,6 +3158,26 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
+		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			if (PgArchStartupAllowed())
+				PgArchPID = StartArchiver();
+			continue;
+		}
+
 		/* Was it the system logger?  If so, try to start a new one */
 		if (pid == SysLoggerPID)
 		{
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..d053bf1564 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,9 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Wed_Mar_10_17_51_37_2021_192)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v52-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v45 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index db0cfaa360..aabf9d73eb 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 0786fcf103..430d438303 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -354,6 +354,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Fri_Jan__8_10_24_34_2021_185)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v45-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v46 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index c87ffc6549..a1e51c5b99 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 0786fcf103..430d438303 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -354,6 +354,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Thu_Jan_14_15_14_25_2021_903)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v46-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v47 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index c87ffc6549..a1e51c5b99 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 683ab64f76..6cdaf3753d 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -355,6 +355,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Thu_Jan_21_12_03_48_2021_284)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v47-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v48 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..22e1cd244c 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3143,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3403,7 +3400,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,6 +3606,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3912,6 +3921,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5140,7 +5150,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5204,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5445,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..491747c113 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Fri_Mar__5_17_18_56_2021_497)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v48-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v49 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 174 +++--------------------
 src/backend/postmaster/postmaster.c      |  88 ++++++------
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 83 insertions(+), 232 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..e237cedaff 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,25 +79,17 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -105,121 +98,9 @@ static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +112,24 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..d9f8d82650 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3126,6 +3127,18 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  We treat it the same way to WAL receiver.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			continue;
+		}
+
 		/*
 		 * Was it the autovacuum launcher?	Normal exit can be ignored; we'll
 		 * start a new one at the next iteration of the postmaster's main
@@ -3141,24 +3154,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3403,7 +3398,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3604,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3904,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -4989,6 +4982,19 @@ SubPostmasterMain(int argc, char *argv[])
 
 		AuxiliaryProcessMain(argc - 2, argv + 2);	/* does not return */
 	}
+	if (strcmp(argv[1], "--forkarch") == 0)
+	{
+		/* Restore basic shared memory pointers */
+		InitShmemAccess(UsedShmemSegAddr);
+
+		/* Need a PGPROC to run CreateSharedMemoryAndSemaphores */
+		InitAuxiliaryProcess();
+
+		/* Attach process to shared data structures */
+		CreateSharedMemoryAndSemaphores();
+
+		PgArchiverMain(); /* does not return */
+	}
 	if (strcmp(argv[1], "--forkavlauncher") == 0)
 	{
 		/* Restore basic shared memory pointers */
@@ -5037,12 +5043,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5140,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5194,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5435,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d73890b228 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,8 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Tue_Mar__9_16_53_11_2021_575)--
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Content-Transfer-Encoding: 7bit
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 filename="v49-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v50 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 174 +++--------------------
 src/backend/postmaster/postmaster.c      |  88 ++++++------
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 83 insertions(+), 232 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..e237cedaff 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,25 +79,17 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -105,121 +98,9 @@ static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +112,24 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..d9f8d82650 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3126,6 +3127,18 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  We treat it the same way to WAL receiver.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			continue;
+		}
+
 		/*
 		 * Was it the autovacuum launcher?	Normal exit can be ignored; we'll
 		 * start a new one at the next iteration of the postmaster's main
@@ -3141,24 +3154,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3403,7 +3398,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3604,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3904,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -4989,6 +4982,19 @@ SubPostmasterMain(int argc, char *argv[])
 
 		AuxiliaryProcessMain(argc - 2, argv + 2);	/* does not return */
 	}
+	if (strcmp(argv[1], "--forkarch") == 0)
+	{
+		/* Restore basic shared memory pointers */
+		InitShmemAccess(UsedShmemSegAddr);
+
+		/* Need a PGPROC to run CreateSharedMemoryAndSemaphores */
+		InitAuxiliaryProcess();
+
+		/* Attach process to shared data structures */
+		CreateSharedMemoryAndSemaphores();
+
+		PgArchiverMain(); /* does not return */
+	}
 	if (strcmp(argv[1], "--forkavlauncher") == 0)
 	{
 		/* Restore basic shared memory pointers */
@@ -5037,12 +5043,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5140,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5194,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5435,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d73890b228 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,8 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Tue_Mar__9_18_29_34_2021_806)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v50-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v51 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 194 ++++-------------------
 src/backend/postmaster/postmaster.c      |  83 +++++-----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 94 insertions(+), 236 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..c219780c60 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,13 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,148 +75,29 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +109,27 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +602,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ *  exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	ProcGlobal->archiverLatch = NULL;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..fd509869aa 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3141,24 +3142,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3175,6 +3158,26 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving of remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
+		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			if (PgArchStartupAllowed())
+				PgArchPID = StartArchiver();
+			continue;
+		}
+
 		/* Was it the system logger?  If so, try to start a new one */
 		if (pid == SysLoggerPID)
 		{
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d71700a565 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -350,6 +350,8 @@ typedef struct PROC_HDR
 	Latch	   *walwriterLatch;
 	/* Checkpointer process's latch */
 	Latch	   *checkpointerLatch;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 	/* Current shared estimate of appropriate spins_per_delay value */
 	int			spins_per_delay;
 	/* The proc of the Startup process, since not in ProcArray */
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Wed_Mar_10_12_10_39_2021_432)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v51-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v52 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 224 ++++++++---------------
 src/backend/postmaster/postmaster.c      |  83 ++++-----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  13 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 9 files changed, 139 insertions(+), 222 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..2558bcfb08 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,13 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +493,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..c399e6c267 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,68 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	Latch	*latch;		/* latch to wake the archiver up */
+	slock_t  mutex;		/* locks this struct */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size	size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
+	return size;
+}
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool	found;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver ", PgArchShmemSize(), &found);
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
+	if (!found)
 	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
+		SpinLockInit(&PgArch->mutex);
+		PgArch->latch = NULL;
 	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
 }
-#endif							/* EXEC_BACKEND */
-
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +144,48 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = MyLatch;
+	SpinLockRelease(&PgArch->mutex);
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	Latch	*latch;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
+	SpinLockAcquire(&PgArch->mutex);
+	latch = PgArch->latch;
+	SpinLockRelease(&PgArch->mutex);
 
-	errno = save_errno;
+	if (latch)
+		SetLatch(latch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +210,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +248,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +270,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +656,17 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ *  exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = NULL;
+	SpinLockRelease(&PgArch->mutex);
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..34c8551288 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3141,24 +3142,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3175,6 +3158,26 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
+		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			if (PgArchStartupAllowed())
+				PgArchPID = StartArchiver();
+			continue;
+		}
+
 		/* Was it the system logger?  If so, try to start a new one */
 		if (pid == SysLoggerPID)
 		{
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..d053bf1564 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,9 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Wed_Mar_10_17_51_37_2021_192)--
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Content-Transfer-Encoding: 7bit
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 filename="v52-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v45 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index db0cfaa360..aabf9d73eb 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 0786fcf103..430d438303 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -354,6 +354,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Fri_Jan__8_10_24_34_2021_185)--
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Content-Transfer-Encoding: 7bit
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^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v46 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index c87ffc6549..a1e51c5b99 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 0786fcf103..430d438303 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -354,6 +354,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Thu_Jan_14_15_14_25_2021_903)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v46-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v47 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7de27ee4e0..af91c313e2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1788,7 +1789,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3027,7 +3028,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3162,20 +3163,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3423,7 +3420,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3629,6 +3626,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3932,6 +3941,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5160,7 +5170,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5214,16 +5224,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5465,6 +5465,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index c87ffc6549..a1e51c5b99 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 683ab64f76..6cdaf3753d 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -355,6 +355,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Thu_Jan_21_12_03_48_2021_284)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v47-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v48 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++--
 src/backend/postmaster/pgarch.c          | 130 +++--------------------
 src/backend/postmaster/postmaster.c      |  50 +++++----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/access/xlog.h                |   3 +
 src/include/access/xlogarchive.h         |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |   4 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   3 +
 11 files changed, 69 insertions(+), 154 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..d01859bde5 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,9 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
+#include "storage/latch.h"
 #include "storage/pmsignal.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +492,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..9a2e21bf86 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,13 +79,11 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
@@ -95,8 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -110,75 +107,6 @@ static void pgarch_archiveDone(char *xlog);
  * ------------------------------------------------------------
  */
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
 /* ------------------------------------------------------------
  * Local functions called by archiver follow
  * ------------------------------------------------------------
@@ -212,14 +140,9 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +154,26 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
 	exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
-}
-
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +198,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +236,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +258,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..22e1cd244c 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3143,16 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 * Was it the archiver?  Normal exit can be ignored; we'll start a new
+		 * one at the next iteration of the postmaster's main loop, if
+		 * necessary. Any other exit condition is treated as a crash.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
 			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			continue;
 		}
 
@@ -3403,7 +3400,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,6 +3606,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
+	{
+		ereport(DEBUG2,
+				(errmsg_internal("sending %s to process %d",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
+								 (int) PgArchPID)));
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
+	}
+
 	/*
 	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
 	 * necessary, but it seems like a good idea for robustness, and it
@@ -3912,6 +3921,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5140,7 +5150,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5204,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5445,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 75ec1073bd..551f518cc2 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -339,6 +339,9 @@ extern XLogRecPtr GetRedoRecPtr(void);
 extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
+extern void XLogArchiveWakeupStart(void);
+extern void XLogArchiveWakeupEnd(void);
+extern void XLogArchiveWakeup(void);
 extern void RemovePromoteSignalFiles(void);
 
 extern bool PromoteIsTriggered(void);
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.h
index 3edd1a976c..1a59181cf9 100644
--- a/src/include/access/xlogarchive.h
+++ b/src/include/access/xlogarchive.h
@@ -25,6 +25,7 @@ extern void ExecuteRecoveryCommand(const char *command, const char *commandName,
 extern void KeepFileRestoredFromArchive(const char *path, const char *xlogfname);
 extern void XLogArchiveNotify(const char *xlog);
 extern void XLogArchiveNotifySeg(XLogSegNo segno);
+extern void XLogArchiveWakeup(void);
 extern void XLogArchiveForceDone(const char *xlog);
 extern bool XLogArchiveCheckDone(const char *xlog);
 extern bool XLogArchiveIsBusy(const char *xlog);
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..385b002dfe 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -32,8 +32,6 @@
  */
 extern int	pgarch_start(void);
 
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..491747c113 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,9 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
+	/* Current shared estimate of appropriate spins_per_delay value */
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
-- 
2.27.0


----Next_Part(Fri_Mar__5_17_18_56_2021_497)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v48-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v49 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 174 +++--------------------
 src/backend/postmaster/postmaster.c      |  88 ++++++------
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 83 insertions(+), 232 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..e237cedaff 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,25 +79,17 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -105,121 +98,9 @@ static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +112,24 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..d9f8d82650 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3126,6 +3127,18 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  We treat it the same way to WAL receiver.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			continue;
+		}
+
 		/*
 		 * Was it the autovacuum launcher?	Normal exit can be ignored; we'll
 		 * start a new one at the next iteration of the postmaster's main
@@ -3141,24 +3154,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3403,7 +3398,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3604,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3904,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -4989,6 +4982,19 @@ SubPostmasterMain(int argc, char *argv[])
 
 		AuxiliaryProcessMain(argc - 2, argv + 2);	/* does not return */
 	}
+	if (strcmp(argv[1], "--forkarch") == 0)
+	{
+		/* Restore basic shared memory pointers */
+		InitShmemAccess(UsedShmemSegAddr);
+
+		/* Need a PGPROC to run CreateSharedMemoryAndSemaphores */
+		InitAuxiliaryProcess();
+
+		/* Attach process to shared data structures */
+		CreateSharedMemoryAndSemaphores();
+
+		PgArchiverMain(); /* does not return */
+	}
 	if (strcmp(argv[1], "--forkavlauncher") == 0)
 	{
 		/* Restore basic shared memory pointers */
@@ -5037,12 +5043,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5140,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5194,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5435,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d73890b228 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,8 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Tue_Mar__9_16_53_11_2021_575)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v49-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v50 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 174 +++--------------------
 src/backend/postmaster/postmaster.c      |  88 ++++++------
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 83 insertions(+), 232 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..e237cedaff 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -48,6 +48,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,25 +79,17 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -105,121 +98,9 @@ static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +112,24 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..d9f8d82650 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3126,6 +3127,18 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  We treat it the same way to WAL receiver.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			continue;
+		}
+
 		/*
 		 * Was it the autovacuum launcher?	Normal exit can be ignored; we'll
 		 * start a new one at the next iteration of the postmaster's main
@@ -3141,24 +3154,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3403,7 +3398,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3604,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3904,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -4989,6 +4982,19 @@ SubPostmasterMain(int argc, char *argv[])
 
 		AuxiliaryProcessMain(argc - 2, argv + 2);	/* does not return */
 	}
+	if (strcmp(argv[1], "--forkarch") == 0)
+	{
+		/* Restore basic shared memory pointers */
+		InitShmemAccess(UsedShmemSegAddr);
+
+		/* Need a PGPROC to run CreateSharedMemoryAndSemaphores */
+		InitAuxiliaryProcess();
+
+		/* Attach process to shared data structures */
+		CreateSharedMemoryAndSemaphores();
+
+		PgArchiverMain(); /* does not return */
+	}
 	if (strcmp(argv[1], "--forkavlauncher") == 0)
 	{
 		/* Restore basic shared memory pointers */
@@ -5037,12 +5043,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5140,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5194,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5435,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d73890b228 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -357,6 +357,8 @@ typedef struct PROC_HDR
 	int			startupProcPid;
 	/* Buffer id of the buffer that Startup process waits for pin on, or -1 */
 	int			startupBufferPinWaitBufId;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 } PROC_HDR;
 
 extern PGDLLIMPORT PROC_HDR *ProcGlobal;
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Tue_Mar__9_18_29_34_2021_806)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v50-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v51 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   7 +-
 src/backend/bootstrap/bootstrap.c        |  22 +--
 src/backend/postmaster/pgarch.c          | 194 ++++-------------------
 src/backend/postmaster/postmaster.c      |  83 +++++-----
 src/backend/storage/lmgr/proc.c          |   1 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  10 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |  10 +-
 9 files changed, 94 insertions(+), 236 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..8b66a30931 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -29,7 +29,8 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -490,8 +491,8 @@ XLogArchiveNotify(const char *xlog)
 	}
 
 	/* Notify archiver that it's got something to do */
-	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+	if (IsUnderPostmaster && ProcGlobal->archiverLatch)
+		SetLatch(ProcGlobal->archiverLatch);
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..c219780c60 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,13 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -78,148 +75,29 @@
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
-
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
-}
-#endif							/* EXEC_BACKEND */
-
-
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,31 +109,27 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	ProcGlobal->archiverLatch = &MyProc->procLatch;
 
 	pgarch_MainLoop();
 
-	exit(0);
-}
-
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	proc_exit(0);
 }
 
 /* SIGUSR2 signal handler for archiver process */
@@ -282,14 +156,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +194,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +216,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +602,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ *  exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	ProcGlobal->archiverLatch = NULL;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..fd509869aa 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3141,24 +3142,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3175,6 +3158,26 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving of remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
+		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			if (PgArchStartupAllowed())
+				PgArchPID = StartArchiver();
+			continue;
+		}
+
 		/* Was it the system logger?  If so, try to start a new one */
 		if (pid == SysLoggerPID)
 		{
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 897045ee27..bf5d6da89b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -182,6 +182,7 @@ InitProcGlobal(void)
 	ProcGlobal->startupBufferPinWaitBufId = -1;
 	ProcGlobal->walwriterLatch = NULL;
 	ProcGlobal->checkpointerLatch = NULL;
+	ProcGlobal->archiverLatch = NULL;
 	pg_atomic_init_u32(&ProcGlobal->procArrayGroupFirst, INVALID_PGPROCNO);
 	pg_atomic_init_u32(&ProcGlobal->clogGroupFirst, INVALID_PGPROCNO);
 
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..737ed69e57 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,6 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern void PgArchiverMain(void) pg_attribute_noreturn();
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..d71700a565 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -350,6 +350,8 @@ typedef struct PROC_HDR
 	Latch	   *walwriterLatch;
 	/* Checkpointer process's latch */
 	Latch	   *checkpointerLatch;
+	/* Archiver process's latch */
+	Latch	   *archiverLatch;
 	/* Current shared estimate of appropriate spins_per_delay value */
 	int			spins_per_delay;
 	/* The proc of the Startup process, since not in ProcArray */
@@ -370,11 +372,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Wed_Mar_10_12_10_39_2021_432)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v51-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v52 3/7] Make archiver process an auxiliary process
@ 2020-03-13 07:59  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:59 UTC (permalink / raw)

This is a preliminary patch for shared-memory based stats collector.

Archiver process must be a auxiliary process since it uses shared
memory after stats data was moved into shared-memory. Make the process
an auxiliary process in order to make it work.
---
 src/backend/access/transam/xlogarchive.c |   6 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 224 ++++++++---------------
 src/backend/postmaster/postmaster.c      |  83 ++++-----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  13 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 9 files changed, 139 insertions(+), 222 deletions(-)

diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..2558bcfb08 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,13 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
+#include "storage/latch.h"
+#include "storage/proc.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +493,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..c399e6c267 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,68 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	Latch	*latch;		/* latch to wake the archiver up */
+	slock_t  mutex;		/* locks this struct */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size	size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
+	return size;
+}
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool	found;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver ", PgArchShmemSize(), &found);
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
+	if (!found)
 	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
+		SpinLockInit(&PgArch->mutex);
+		PgArch->latch = NULL;
 	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
 }
-#endif							/* EXEC_BACKEND */
-
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +144,48 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = MyLatch;
+	SpinLockRelease(&PgArch->mutex);
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	Latch	*latch;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
+	SpinLockAcquire(&PgArch->mutex);
+	latch = PgArch->latch;
+	SpinLockRelease(&PgArch->mutex);
 
-	errno = save_errno;
+	if (latch)
+		SetLatch(latch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +210,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +248,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +270,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +656,17 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ *  exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = NULL;
+	SpinLockRelease(&PgArch->mutex);
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..34c8551288 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3141,24 +3142,6 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
-		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
-		 * PostmasterStateMachine() will advance to the next shutdown step.
-		 */
-		if (pid == PgArchPID)
-		{
-			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
-			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
-			continue;
-		}
-
 		/*
 		 * Was it the statistics collector?  If so, just try to start a new
 		 * one; no need to force reset of the rest of the system.  (If fail,
@@ -3175,6 +3158,26 @@ reaper(SIGNAL_ARGS)
 			continue;
 		}
 
+		/*
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
+		 * PostmasterStateMachine() will advance to the next shutdown step.
+		 */
+		if (pid == PgArchPID)
+		{
+			PgArchPID = 0;
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
+			if (PgArchStartupAllowed())
+				PgArchPID = StartArchiver();
+			continue;
+		}
+
 		/* Was it the system logger?  If so, try to start a new one */
 		if (pid == SysLoggerPID)
 		{
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1bdc97e308..adb9f819bb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -419,6 +419,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -431,6 +432,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..d053bf1564 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,9 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
-- 
2.27.0


----Next_Part(Wed_Mar_10_17_51_37_2021_192)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v52-0004-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v53 3/7] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 227 ++++++++---------------
 src/backend/postmaster/postmaster.c      |  74 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  13 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 137 insertions(+), 218 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..818c9a1f3f 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,70 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	Latch	   *latch;			/* latch to wake the archiver up */
+	slock_t		mutex;			/* locks this struct */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size		size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
+	return size;
+}
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
+	if (!found)
 	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		SpinLockInit(&PgArch->mutex);
+		PgArch->latch = NULL;
 	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
 }
-#endif							/* EXEC_BACKEND */
-
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +146,49 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = MyLatch;
+	SpinLockRelease(&PgArch->mutex);
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	Latch	   *latch;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
+	/* fetching the latch pointer might not be atomic, so use spinlock */
+	SpinLockAcquire(&PgArch->mutex);
+	latch = PgArch->latch;
+	SpinLockRelease(&PgArch->mutex);
 
-	errno = save_errno;
+	if (latch)
+		SetLatch(latch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +213,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +251,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +273,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +659,17 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = NULL;
+	SpinLockRelease(&PgArch->mutex);
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..460e629145 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3143,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3804,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and syslogger
+		 * processes are disregarded since they are not connected to shared
+		 * memory; we also disregard dead_end children here. Walsenders and
+		 * archiver are also disregarded, they will be terminated later after
+		 * writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3911,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5037,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5134,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5188,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5429,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..d053bf1564 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,9 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_09_23_13_2021_947)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v54 3/7] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 241 +++++++++--------------
 src/backend/postmaster/postmaster.c      |  81 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  14 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 160 insertions(+), 217 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..8e572afea3 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,6 +71,12 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	int		pgprocno;				/* pgprocno of archiver process */
+} PgArchData;
+
 
 /* ----------
  * Local data
@@ -80,146 +84,79 @@
  */
 static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size		size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
+
+	return size;
+}
+
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
+
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
+
+	if (!found)
+	{
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		PgArch->pgprocno = INVALID_PGPROCNO;
+	}
+}
 
 /*
- * pgarch_start
+ *  PgArchIsSuppressed
  *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
+ * Return true if archiver relaunch is suppressed.
  *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
+ * This is a safety valve to protect against continuous respawn attempts if the
+ * archiver is dying immediately at launch. Note that since we will retry to
+ * launch the archiver from the postmaster main loop, we will get another
+ * chance later.
  */
-int
-pgarch_start(void)
+bool
+PgArchIsSuppressed(void)
 {
-	time_t		curtime;
-	pid_t		pgArchPid;
+	time_t	curtime = time(NULL);
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+	if ((curtime - last_pgarch_start_time) < PGARCH_RESTART_INTERVAL)
+		return true;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
 	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
+	return false;
 }
-#endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +168,51 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* We shouldn't be launched unnecessarily. */
+	Assert(XLogArchivingActive());
+
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	PgArch->pgprocno = MyProc->pgprocno;
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	int	arch_pgprocno = PgArch->pgprocno;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	/*
+	 * We don't acquire ProcArrayLock here.  It's actually fine because
+	 * procLatch isn't ever freed, so we just can potentially set the wrong
+	 * process' (or no process') latch.  Even in that case the archiver will be
+	 * relaunched shortly and will start archiving.
+	 */
+	if (arch_pgprocno != INVALID_PGPROCNO)
+		SetLatch(&ProcGlobal->allProcs[arch_pgprocno].procLatch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +237,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +275,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +297,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +683,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	PgArch->pgprocno = INVALID_PGPROCNO;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..4f8e364284 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -443,9 +443,10 @@ static void InitPostmasterDeathWatchHandle(void);
  * even during recovery.
  */
 #define PgArchStartupAllowed()	\
-	((XLogArchivingActive() && pmState == PM_RUN) ||	\
-	 (XLogArchivingAlways() &&	\
-	  (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY)))
+	(((XLogArchivingActive() && pmState == PM_RUN) ||	\
+	  (XLogArchivingAlways() &&									\
+	   (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY))) && \
+	 !PgArchIsSuppressed())
 
 #ifdef EXEC_BACKEND
 
@@ -548,6 +549,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1794,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3009,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3144,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3407,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3613,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3805,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and syslogger
+		 * processes are disregarded since they are not connected to shared
+		 * memory; we also disregard dead_end children here. Walsenders and
+		 * archiver are also disregarded, they will be terminated later after
+		 * writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..640692d33e 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,10 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern bool PgArchIsSuppressed(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_13_49_06_2021_682)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v55 3/3] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 240 ++++++++++-------------
 src/backend/postmaster/postmaster.c      |  81 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  14 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 164 insertions(+), 212 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..07ba989a37 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,101 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	int			pgprocno;		/* pgprocno of archiver process */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
-
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
 {
-	time_t		curtime;
-	pid_t		pgArchPid;
+	Size		size = 0;
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	size = add_size(size, sizeof(PgArchData));
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
+	return size;
+}
 
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
 
-			PgArchiverMain(0, NULL);
-			break;
-#endif
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
 
-		default:
-			return (int) pgArchPid;
+	if (!found)
+	{
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		PgArch->pgprocno = INVALID_PGPROCNO;
 	}
-
-	/* shouldn't get here */
-	return 0;
 }
 
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
 /*
- * pgarch_forkexec() -
+ *  PgArchIsSuppressed
  *
- * Format up the arglist for, then fork and exec, archive process
+ * Return true if archiver relaunch is suppressed.
+ *
+ * This is a safety valve to protect against continuous respawn attempts if the
+ * archiver is dying immediately at launch. Note that since we will retry to
+ * launch the archiver from the postmaster main loop, we will get another
+ * chance later.
  */
-static pid_t
-pgarch_forkexec(void)
+bool
+PgArchCanRestart(void)
 {
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
+	static time_t last_pgarch_start_time = 0;
+	time_t		curtime = time(NULL);
 
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
+	/*
+	 * allow to launch also for the first time and when something's wrong in
+	 * the time values.
+	 */
+	if (last_pgarch_start_time == 0 ||
+		curtime < last_pgarch_start_time ||
+		(curtime - last_pgarch_start_time) >= PGARCH_RESTART_INTERVAL)
+	{
+		last_pgarch_start_time = curtime;
 
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
+		return true;
+	}
 
-	return postmaster_forkexec(ac, av);
+	return false;
 }
-#endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +177,51 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* We shouldn't be launched unnecessarily. */
+	Assert(XLogArchivingActive());
+
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our pgproc index so that backends can use our latch to wake
+	 * us up while we're sleeping.
+	 */
+	PgArch->pgprocno = MyProc->pgprocno;
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	int			arch_pgprocno = PgArch->pgprocno;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	/*
+	 * We don't acquire ProcArrayLock here.  It's actually fine because
+	 * procLatch isn't ever freed, so we just can potentially set the wrong
+	 * process' (or no process') latch.  Even in that case the archiver will
+	 * be relaunched shortly and will start archiving.
+	 */
+	if (arch_pgprocno != INVALID_PGPROCNO)
+		SetLatch(&ProcGlobal->allProcs[arch_pgprocno].procLatch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +246,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +284,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +306,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +692,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	PgArch->pgprocno = INVALID_PGPROCNO;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..e8af05c04e 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -443,9 +443,10 @@ static void InitPostmasterDeathWatchHandle(void);
  * even during recovery.
  */
 #define PgArchStartupAllowed()	\
-	((XLogArchivingActive() && pmState == PM_RUN) ||	\
-	 (XLogArchivingAlways() &&	\
-	  (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY)))
+	(((XLogArchivingActive() && pmState == PM_RUN) ||			\
+	  (XLogArchivingAlways() &&									  \
+	   (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY))) && \
+	 PgArchCanRestart())
 
 #ifdef EXEC_BACKEND
 
@@ -548,6 +549,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1794,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3009,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3144,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for
+		 * it to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3407,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3613,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3805,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and
+		 * syslogger processes are disregarded since they are not connected to
+		 * shared memory; we also disregard dead_end children here. Walsenders
+		 * and archiver are also disregarded, they will be terminated later
+		 * after writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..1e47a143e1 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,10 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern bool PgArchCanRestart(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_17_24_43_2021_866)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v54 3/7] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 241 +++++++++--------------
 src/backend/postmaster/postmaster.c      |  81 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  14 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 160 insertions(+), 217 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..8e572afea3 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,6 +71,12 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	int		pgprocno;				/* pgprocno of archiver process */
+} PgArchData;
+
 
 /* ----------
  * Local data
@@ -80,146 +84,79 @@
  */
 static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size		size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
+
+	return size;
+}
+
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
+
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
+
+	if (!found)
+	{
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		PgArch->pgprocno = INVALID_PGPROCNO;
+	}
+}
 
 /*
- * pgarch_start
+ *  PgArchIsSuppressed
  *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
+ * Return true if archiver relaunch is suppressed.
  *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
+ * This is a safety valve to protect against continuous respawn attempts if the
+ * archiver is dying immediately at launch. Note that since we will retry to
+ * launch the archiver from the postmaster main loop, we will get another
+ * chance later.
  */
-int
-pgarch_start(void)
+bool
+PgArchIsSuppressed(void)
 {
-	time_t		curtime;
-	pid_t		pgArchPid;
+	time_t	curtime = time(NULL);
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+	if ((curtime - last_pgarch_start_time) < PGARCH_RESTART_INTERVAL)
+		return true;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
 	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
+	return false;
 }
-#endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +168,51 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* We shouldn't be launched unnecessarily. */
+	Assert(XLogArchivingActive());
+
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	PgArch->pgprocno = MyProc->pgprocno;
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	int	arch_pgprocno = PgArch->pgprocno;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	/*
+	 * We don't acquire ProcArrayLock here.  It's actually fine because
+	 * procLatch isn't ever freed, so we just can potentially set the wrong
+	 * process' (or no process') latch.  Even in that case the archiver will be
+	 * relaunched shortly and will start archiving.
+	 */
+	if (arch_pgprocno != INVALID_PGPROCNO)
+		SetLatch(&ProcGlobal->allProcs[arch_pgprocno].procLatch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +237,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +275,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +297,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +683,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	PgArch->pgprocno = INVALID_PGPROCNO;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..4f8e364284 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -443,9 +443,10 @@ static void InitPostmasterDeathWatchHandle(void);
  * even during recovery.
  */
 #define PgArchStartupAllowed()	\
-	((XLogArchivingActive() && pmState == PM_RUN) ||	\
-	 (XLogArchivingAlways() &&	\
-	  (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY)))
+	(((XLogArchivingActive() && pmState == PM_RUN) ||	\
+	  (XLogArchivingAlways() &&									\
+	   (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY))) && \
+	 !PgArchIsSuppressed())
 
 #ifdef EXEC_BACKEND
 
@@ -548,6 +549,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1794,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3009,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3144,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3407,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3613,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3805,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and syslogger
+		 * processes are disregarded since they are not connected to shared
+		 * memory; we also disregard dead_end children here. Walsenders and
+		 * archiver are also disregarded, they will be terminated later after
+		 * writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..640692d33e 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,10 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern bool PgArchIsSuppressed(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_13_49_06_2021_682)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v53 3/7] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 227 ++++++++---------------
 src/backend/postmaster/postmaster.c      |  74 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  13 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 137 insertions(+), 218 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..818c9a1f3f 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,70 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	Latch	   *latch;			/* latch to wake the archiver up */
+	slock_t		mutex;			/* locks this struct */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size		size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
+	return size;
+}
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
+	if (!found)
 	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		SpinLockInit(&PgArch->mutex);
+		PgArch->latch = NULL;
 	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
 }
-#endif							/* EXEC_BACKEND */
-
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +146,49 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = MyLatch;
+	SpinLockRelease(&PgArch->mutex);
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	Latch	   *latch;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
+	/* fetching the latch pointer might not be atomic, so use spinlock */
+	SpinLockAcquire(&PgArch->mutex);
+	latch = PgArch->latch;
+	SpinLockRelease(&PgArch->mutex);
 
-	errno = save_errno;
+	if (latch)
+		SetLatch(latch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +213,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +251,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +273,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +659,17 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = NULL;
+	SpinLockRelease(&PgArch->mutex);
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..460e629145 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3143,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3804,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and syslogger
+		 * processes are disregarded since they are not connected to shared
+		 * memory; we also disregard dead_end children here. Walsenders and
+		 * archiver are also disregarded, they will be terminated later after
+		 * writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3911,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5037,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5134,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5188,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5429,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..d053bf1564 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,9 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_09_23_13_2021_947)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v54 3/7] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 241 +++++++++--------------
 src/backend/postmaster/postmaster.c      |  81 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  14 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 160 insertions(+), 217 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..8e572afea3 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,6 +71,12 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	int		pgprocno;				/* pgprocno of archiver process */
+} PgArchData;
+
 
 /* ----------
  * Local data
@@ -80,146 +84,79 @@
  */
 static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size		size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
+
+	return size;
+}
+
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
+
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
+
+	if (!found)
+	{
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		PgArch->pgprocno = INVALID_PGPROCNO;
+	}
+}
 
 /*
- * pgarch_start
+ *  PgArchIsSuppressed
  *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
+ * Return true if archiver relaunch is suppressed.
  *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
+ * This is a safety valve to protect against continuous respawn attempts if the
+ * archiver is dying immediately at launch. Note that since we will retry to
+ * launch the archiver from the postmaster main loop, we will get another
+ * chance later.
  */
-int
-pgarch_start(void)
+bool
+PgArchIsSuppressed(void)
 {
-	time_t		curtime;
-	pid_t		pgArchPid;
+	time_t	curtime = time(NULL);
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+	if ((curtime - last_pgarch_start_time) < PGARCH_RESTART_INTERVAL)
+		return true;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
 	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
+	return false;
 }
-#endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +168,51 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* We shouldn't be launched unnecessarily. */
+	Assert(XLogArchivingActive());
+
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	PgArch->pgprocno = MyProc->pgprocno;
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	int	arch_pgprocno = PgArch->pgprocno;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	/*
+	 * We don't acquire ProcArrayLock here.  It's actually fine because
+	 * procLatch isn't ever freed, so we just can potentially set the wrong
+	 * process' (or no process') latch.  Even in that case the archiver will be
+	 * relaunched shortly and will start archiving.
+	 */
+	if (arch_pgprocno != INVALID_PGPROCNO)
+		SetLatch(&ProcGlobal->allProcs[arch_pgprocno].procLatch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +237,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +275,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +297,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +683,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	PgArch->pgprocno = INVALID_PGPROCNO;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..4f8e364284 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -443,9 +443,10 @@ static void InitPostmasterDeathWatchHandle(void);
  * even during recovery.
  */
 #define PgArchStartupAllowed()	\
-	((XLogArchivingActive() && pmState == PM_RUN) ||	\
-	 (XLogArchivingAlways() &&	\
-	  (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY)))
+	(((XLogArchivingActive() && pmState == PM_RUN) ||	\
+	  (XLogArchivingAlways() &&									\
+	   (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY))) && \
+	 !PgArchIsSuppressed())
 
 #ifdef EXEC_BACKEND
 
@@ -548,6 +549,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1794,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3009,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3144,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3407,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3613,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3805,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and syslogger
+		 * processes are disregarded since they are not connected to shared
+		 * memory; we also disregard dead_end children here. Walsenders and
+		 * archiver are also disregarded, they will be terminated later after
+		 * writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..640692d33e 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,10 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern bool PgArchIsSuppressed(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_13_49_06_2021_682)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v53 3/7] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 227 ++++++++---------------
 src/backend/postmaster/postmaster.c      |  74 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  13 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 137 insertions(+), 218 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..818c9a1f3f 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,70 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	Latch	   *latch;			/* latch to wake the archiver up */
+	slock_t		mutex;			/* locks this struct */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size		size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
+	return size;
+}
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
+	if (!found)
 	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		SpinLockInit(&PgArch->mutex);
+		PgArch->latch = NULL;
 	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
 }
-#endif							/* EXEC_BACKEND */
-
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +146,49 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = MyLatch;
+	SpinLockRelease(&PgArch->mutex);
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	Latch	   *latch;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
+	/* fetching the latch pointer might not be atomic, so use spinlock */
+	SpinLockAcquire(&PgArch->mutex);
+	latch = PgArch->latch;
+	SpinLockRelease(&PgArch->mutex);
 
-	errno = save_errno;
+	if (latch)
+		SetLatch(latch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +213,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +251,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +273,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +659,17 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = NULL;
+	SpinLockRelease(&PgArch->mutex);
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..460e629145 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3143,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3804,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and syslogger
+		 * processes are disregarded since they are not connected to shared
+		 * memory; we also disregard dead_end children here. Walsenders and
+		 * archiver are also disregarded, they will be terminated later after
+		 * writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3911,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5037,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5134,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5188,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5429,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..d053bf1564 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,9 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_09_23_13_2021_947)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v54 3/7] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 241 +++++++++--------------
 src/backend/postmaster/postmaster.c      |  81 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  14 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 160 insertions(+), 217 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..8e572afea3 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,6 +71,12 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	int		pgprocno;				/* pgprocno of archiver process */
+} PgArchData;
+
 
 /* ----------
  * Local data
@@ -80,146 +84,79 @@
  */
 static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size		size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
+
+	return size;
+}
+
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
+
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
+
+	if (!found)
+	{
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		PgArch->pgprocno = INVALID_PGPROCNO;
+	}
+}
 
 /*
- * pgarch_start
+ *  PgArchIsSuppressed
  *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
+ * Return true if archiver relaunch is suppressed.
  *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
+ * This is a safety valve to protect against continuous respawn attempts if the
+ * archiver is dying immediately at launch. Note that since we will retry to
+ * launch the archiver from the postmaster main loop, we will get another
+ * chance later.
  */
-int
-pgarch_start(void)
+bool
+PgArchIsSuppressed(void)
 {
-	time_t		curtime;
-	pid_t		pgArchPid;
+	time_t	curtime = time(NULL);
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+	if ((curtime - last_pgarch_start_time) < PGARCH_RESTART_INTERVAL)
+		return true;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
 	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
+	return false;
 }
-#endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +168,51 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* We shouldn't be launched unnecessarily. */
+	Assert(XLogArchivingActive());
+
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	PgArch->pgprocno = MyProc->pgprocno;
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	int	arch_pgprocno = PgArch->pgprocno;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	/*
+	 * We don't acquire ProcArrayLock here.  It's actually fine because
+	 * procLatch isn't ever freed, so we just can potentially set the wrong
+	 * process' (or no process') latch.  Even in that case the archiver will be
+	 * relaunched shortly and will start archiving.
+	 */
+	if (arch_pgprocno != INVALID_PGPROCNO)
+		SetLatch(&ProcGlobal->allProcs[arch_pgprocno].procLatch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +237,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +275,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +297,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +683,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	PgArch->pgprocno = INVALID_PGPROCNO;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..4f8e364284 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -443,9 +443,10 @@ static void InitPostmasterDeathWatchHandle(void);
  * even during recovery.
  */
 #define PgArchStartupAllowed()	\
-	((XLogArchivingActive() && pmState == PM_RUN) ||	\
-	 (XLogArchivingAlways() &&	\
-	  (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY)))
+	(((XLogArchivingActive() && pmState == PM_RUN) ||	\
+	  (XLogArchivingAlways() &&									\
+	   (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY))) && \
+	 !PgArchIsSuppressed())
 
 #ifdef EXEC_BACKEND
 
@@ -548,6 +549,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1794,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3009,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3144,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3407,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3613,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3805,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and syslogger
+		 * processes are disregarded since they are not connected to shared
+		 * memory; we also disregard dead_end children here. Walsenders and
+		 * archiver are also disregarded, they will be terminated later after
+		 * writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..640692d33e 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,10 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern bool PgArchIsSuppressed(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_13_49_06_2021_682)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v55 3/3] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 240 ++++++++++-------------
 src/backend/postmaster/postmaster.c      |  81 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  14 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 164 insertions(+), 212 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..07ba989a37 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,101 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	int			pgprocno;		/* pgprocno of archiver process */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
-
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
 {
-	time_t		curtime;
-	pid_t		pgArchPid;
+	Size		size = 0;
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	size = add_size(size, sizeof(PgArchData));
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
+	return size;
+}
 
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
 
-			PgArchiverMain(0, NULL);
-			break;
-#endif
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
 
-		default:
-			return (int) pgArchPid;
+	if (!found)
+	{
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		PgArch->pgprocno = INVALID_PGPROCNO;
 	}
-
-	/* shouldn't get here */
-	return 0;
 }
 
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
 /*
- * pgarch_forkexec() -
+ *  PgArchIsSuppressed
  *
- * Format up the arglist for, then fork and exec, archive process
+ * Return true if archiver relaunch is suppressed.
+ *
+ * This is a safety valve to protect against continuous respawn attempts if the
+ * archiver is dying immediately at launch. Note that since we will retry to
+ * launch the archiver from the postmaster main loop, we will get another
+ * chance later.
  */
-static pid_t
-pgarch_forkexec(void)
+bool
+PgArchCanRestart(void)
 {
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
+	static time_t last_pgarch_start_time = 0;
+	time_t		curtime = time(NULL);
 
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
+	/*
+	 * allow to launch also for the first time and when something's wrong in
+	 * the time values.
+	 */
+	if (last_pgarch_start_time == 0 ||
+		curtime < last_pgarch_start_time ||
+		(curtime - last_pgarch_start_time) >= PGARCH_RESTART_INTERVAL)
+	{
+		last_pgarch_start_time = curtime;
 
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
+		return true;
+	}
 
-	return postmaster_forkexec(ac, av);
+	return false;
 }
-#endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +177,51 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* We shouldn't be launched unnecessarily. */
+	Assert(XLogArchivingActive());
+
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our pgproc index so that backends can use our latch to wake
+	 * us up while we're sleeping.
+	 */
+	PgArch->pgprocno = MyProc->pgprocno;
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	int			arch_pgprocno = PgArch->pgprocno;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	/*
+	 * We don't acquire ProcArrayLock here.  It's actually fine because
+	 * procLatch isn't ever freed, so we just can potentially set the wrong
+	 * process' (or no process') latch.  Even in that case the archiver will
+	 * be relaunched shortly and will start archiving.
+	 */
+	if (arch_pgprocno != INVALID_PGPROCNO)
+		SetLatch(&ProcGlobal->allProcs[arch_pgprocno].procLatch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +246,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +284,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +306,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +692,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	PgArch->pgprocno = INVALID_PGPROCNO;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..e8af05c04e 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -443,9 +443,10 @@ static void InitPostmasterDeathWatchHandle(void);
  * even during recovery.
  */
 #define PgArchStartupAllowed()	\
-	((XLogArchivingActive() && pmState == PM_RUN) ||	\
-	 (XLogArchivingAlways() &&	\
-	  (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY)))
+	(((XLogArchivingActive() && pmState == PM_RUN) ||			\
+	  (XLogArchivingAlways() &&									  \
+	   (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY))) && \
+	 PgArchCanRestart())
 
 #ifdef EXEC_BACKEND
 
@@ -548,6 +549,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1794,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3009,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3144,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for
+		 * it to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3407,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3613,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3805,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and
+		 * syslogger processes are disregarded since they are not connected to
+		 * shared memory; we also disregard dead_end children here. Walsenders
+		 * and archiver are also disregarded, they will be terminated later
+		 * after writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..1e47a143e1 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,10 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern bool PgArchCanRestart(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_17_24_43_2021_866)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v55 3/3] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 240 ++++++++++-------------
 src/backend/postmaster/postmaster.c      |  81 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  14 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 164 insertions(+), 212 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..07ba989a37 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,101 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	int			pgprocno;		/* pgprocno of archiver process */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
-
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
 {
-	time_t		curtime;
-	pid_t		pgArchPid;
+	Size		size = 0;
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	size = add_size(size, sizeof(PgArchData));
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
+	return size;
+}
 
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
 
-			PgArchiverMain(0, NULL);
-			break;
-#endif
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
 
-		default:
-			return (int) pgArchPid;
+	if (!found)
+	{
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		PgArch->pgprocno = INVALID_PGPROCNO;
 	}
-
-	/* shouldn't get here */
-	return 0;
 }
 
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
 /*
- * pgarch_forkexec() -
+ *  PgArchIsSuppressed
  *
- * Format up the arglist for, then fork and exec, archive process
+ * Return true if archiver relaunch is suppressed.
+ *
+ * This is a safety valve to protect against continuous respawn attempts if the
+ * archiver is dying immediately at launch. Note that since we will retry to
+ * launch the archiver from the postmaster main loop, we will get another
+ * chance later.
  */
-static pid_t
-pgarch_forkexec(void)
+bool
+PgArchCanRestart(void)
 {
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
+	static time_t last_pgarch_start_time = 0;
+	time_t		curtime = time(NULL);
 
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
+	/*
+	 * allow to launch also for the first time and when something's wrong in
+	 * the time values.
+	 */
+	if (last_pgarch_start_time == 0 ||
+		curtime < last_pgarch_start_time ||
+		(curtime - last_pgarch_start_time) >= PGARCH_RESTART_INTERVAL)
+	{
+		last_pgarch_start_time = curtime;
 
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
+		return true;
+	}
 
-	return postmaster_forkexec(ac, av);
+	return false;
 }
-#endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +177,51 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* We shouldn't be launched unnecessarily. */
+	Assert(XLogArchivingActive());
+
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our pgproc index so that backends can use our latch to wake
+	 * us up while we're sleeping.
+	 */
+	PgArch->pgprocno = MyProc->pgprocno;
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	int			arch_pgprocno = PgArch->pgprocno;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	/*
+	 * We don't acquire ProcArrayLock here.  It's actually fine because
+	 * procLatch isn't ever freed, so we just can potentially set the wrong
+	 * process' (or no process') latch.  Even in that case the archiver will
+	 * be relaunched shortly and will start archiving.
+	 */
+	if (arch_pgprocno != INVALID_PGPROCNO)
+		SetLatch(&ProcGlobal->allProcs[arch_pgprocno].procLatch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +246,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +284,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +306,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +692,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	PgArch->pgprocno = INVALID_PGPROCNO;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..e8af05c04e 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -443,9 +443,10 @@ static void InitPostmasterDeathWatchHandle(void);
  * even during recovery.
  */
 #define PgArchStartupAllowed()	\
-	((XLogArchivingActive() && pmState == PM_RUN) ||	\
-	 (XLogArchivingAlways() &&	\
-	  (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY)))
+	(((XLogArchivingActive() && pmState == PM_RUN) ||			\
+	  (XLogArchivingAlways() &&									  \
+	   (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY))) && \
+	 PgArchCanRestart())
 
 #ifdef EXEC_BACKEND
 
@@ -548,6 +549,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1794,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3009,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3144,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for
+		 * it to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3407,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3613,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3805,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and
+		 * syslogger processes are disregarded since they are not connected to
+		 * shared memory; we also disregard dead_end children here. Walsenders
+		 * and archiver are also disregarded, they will be terminated later
+		 * after writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..1e47a143e1 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,10 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern bool PgArchCanRestart(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_17_24_43_2021_866)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v55 3/3] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 240 ++++++++++-------------
 src/backend/postmaster/postmaster.c      |  81 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  14 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 164 insertions(+), 212 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..07ba989a37 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,101 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	int			pgprocno;		/* pgprocno of archiver process */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
-
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
 {
-	time_t		curtime;
-	pid_t		pgArchPid;
+	Size		size = 0;
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	size = add_size(size, sizeof(PgArchData));
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
+	return size;
+}
 
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
 
-			PgArchiverMain(0, NULL);
-			break;
-#endif
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
 
-		default:
-			return (int) pgArchPid;
+	if (!found)
+	{
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		PgArch->pgprocno = INVALID_PGPROCNO;
 	}
-
-	/* shouldn't get here */
-	return 0;
 }
 
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
 /*
- * pgarch_forkexec() -
+ *  PgArchIsSuppressed
  *
- * Format up the arglist for, then fork and exec, archive process
+ * Return true if archiver relaunch is suppressed.
+ *
+ * This is a safety valve to protect against continuous respawn attempts if the
+ * archiver is dying immediately at launch. Note that since we will retry to
+ * launch the archiver from the postmaster main loop, we will get another
+ * chance later.
  */
-static pid_t
-pgarch_forkexec(void)
+bool
+PgArchCanRestart(void)
 {
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
+	static time_t last_pgarch_start_time = 0;
+	time_t		curtime = time(NULL);
 
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
+	/*
+	 * allow to launch also for the first time and when something's wrong in
+	 * the time values.
+	 */
+	if (last_pgarch_start_time == 0 ||
+		curtime < last_pgarch_start_time ||
+		(curtime - last_pgarch_start_time) >= PGARCH_RESTART_INTERVAL)
+	{
+		last_pgarch_start_time = curtime;
 
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
+		return true;
+	}
 
-	return postmaster_forkexec(ac, av);
+	return false;
 }
-#endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +177,51 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* We shouldn't be launched unnecessarily. */
+	Assert(XLogArchivingActive());
+
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our pgproc index so that backends can use our latch to wake
+	 * us up while we're sleeping.
+	 */
+	PgArch->pgprocno = MyProc->pgprocno;
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	int			arch_pgprocno = PgArch->pgprocno;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	/*
+	 * We don't acquire ProcArrayLock here.  It's actually fine because
+	 * procLatch isn't ever freed, so we just can potentially set the wrong
+	 * process' (or no process') latch.  Even in that case the archiver will
+	 * be relaunched shortly and will start archiving.
+	 */
+	if (arch_pgprocno != INVALID_PGPROCNO)
+		SetLatch(&ProcGlobal->allProcs[arch_pgprocno].procLatch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +246,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +284,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +306,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +692,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	PgArch->pgprocno = INVALID_PGPROCNO;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..e8af05c04e 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -443,9 +443,10 @@ static void InitPostmasterDeathWatchHandle(void);
  * even during recovery.
  */
 #define PgArchStartupAllowed()	\
-	((XLogArchivingActive() && pmState == PM_RUN) ||	\
-	 (XLogArchivingAlways() &&	\
-	  (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY)))
+	(((XLogArchivingActive() && pmState == PM_RUN) ||			\
+	  (XLogArchivingAlways() &&									  \
+	   (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY))) && \
+	 PgArchCanRestart())
 
 #ifdef EXEC_BACKEND
 
@@ -548,6 +549,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1794,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3009,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3144,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for
+		 * it to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3407,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3613,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3805,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and
+		 * syslogger processes are disregarded since they are not connected to
+		 * shared memory; we also disregard dead_end children here. Walsenders
+		 * and archiver are also disregarded, they will be terminated later
+		 * after writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..1e47a143e1 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,10 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern bool PgArchCanRestart(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_17_24_43_2021_866)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v53 3/7] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 227 ++++++++---------------
 src/backend/postmaster/postmaster.c      |  74 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  13 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 137 insertions(+), 218 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..818c9a1f3f 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,70 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	Latch	   *latch;			/* latch to wake the archiver up */
+	slock_t		mutex;			/* locks this struct */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size		size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
+	return size;
+}
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
+	if (!found)
 	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		SpinLockInit(&PgArch->mutex);
+		PgArch->latch = NULL;
 	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
 }
-#endif							/* EXEC_BACKEND */
-
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +146,49 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = MyLatch;
+	SpinLockRelease(&PgArch->mutex);
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	Latch	   *latch;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
+	/* fetching the latch pointer might not be atomic, so use spinlock */
+	SpinLockAcquire(&PgArch->mutex);
+	latch = PgArch->latch;
+	SpinLockRelease(&PgArch->mutex);
 
-	errno = save_errno;
+	if (latch)
+		SetLatch(latch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +213,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +251,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +273,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +659,17 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = NULL;
+	SpinLockRelease(&PgArch->mutex);
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..460e629145 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3143,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3804,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and syslogger
+		 * processes are disregarded since they are not connected to shared
+		 * memory; we also disregard dead_end children here. Walsenders and
+		 * archiver are also disregarded, they will be terminated later after
+		 * writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3911,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5037,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5134,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5188,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5429,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..d053bf1564 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,9 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_09_23_13_2021_947)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v54 3/7] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 241 +++++++++--------------
 src/backend/postmaster/postmaster.c      |  81 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  14 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 160 insertions(+), 217 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..8e572afea3 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,6 +71,12 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	int		pgprocno;				/* pgprocno of archiver process */
+} PgArchData;
+
 
 /* ----------
  * Local data
@@ -80,146 +84,79 @@
  */
 static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size		size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
+
+	return size;
+}
+
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
+
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
+
+	if (!found)
+	{
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		PgArch->pgprocno = INVALID_PGPROCNO;
+	}
+}
 
 /*
- * pgarch_start
+ *  PgArchIsSuppressed
  *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
+ * Return true if archiver relaunch is suppressed.
  *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
+ * This is a safety valve to protect against continuous respawn attempts if the
+ * archiver is dying immediately at launch. Note that since we will retry to
+ * launch the archiver from the postmaster main loop, we will get another
+ * chance later.
  */
-int
-pgarch_start(void)
+bool
+PgArchIsSuppressed(void)
 {
-	time_t		curtime;
-	pid_t		pgArchPid;
+	time_t	curtime = time(NULL);
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+	if ((curtime - last_pgarch_start_time) < PGARCH_RESTART_INTERVAL)
+		return true;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
 	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
+	return false;
 }
-#endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +168,51 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* We shouldn't be launched unnecessarily. */
+	Assert(XLogArchivingActive());
+
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	PgArch->pgprocno = MyProc->pgprocno;
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	int	arch_pgprocno = PgArch->pgprocno;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	/*
+	 * We don't acquire ProcArrayLock here.  It's actually fine because
+	 * procLatch isn't ever freed, so we just can potentially set the wrong
+	 * process' (or no process') latch.  Even in that case the archiver will be
+	 * relaunched shortly and will start archiving.
+	 */
+	if (arch_pgprocno != INVALID_PGPROCNO)
+		SetLatch(&ProcGlobal->allProcs[arch_pgprocno].procLatch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +237,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +275,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +297,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +683,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	PgArch->pgprocno = INVALID_PGPROCNO;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..4f8e364284 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -443,9 +443,10 @@ static void InitPostmasterDeathWatchHandle(void);
  * even during recovery.
  */
 #define PgArchStartupAllowed()	\
-	((XLogArchivingActive() && pmState == PM_RUN) ||	\
-	 (XLogArchivingAlways() &&	\
-	  (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY)))
+	(((XLogArchivingActive() && pmState == PM_RUN) ||	\
+	  (XLogArchivingAlways() &&									\
+	   (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY))) && \
+	 !PgArchIsSuppressed())
 
 #ifdef EXEC_BACKEND
 
@@ -548,6 +549,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1794,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3009,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3144,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3407,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3613,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3805,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and syslogger
+		 * processes are disregarded since they are not connected to shared
+		 * memory; we also disregard dead_end children here. Walsenders and
+		 * archiver are also disregarded, they will be terminated later after
+		 * writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..640692d33e 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,10 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern bool PgArchIsSuppressed(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_13_49_06_2021_682)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v55 3/3] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 240 ++++++++++-------------
 src/backend/postmaster/postmaster.c      |  81 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  14 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 164 insertions(+), 212 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..07ba989a37 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,101 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	int			pgprocno;		/* pgprocno of archiver process */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
-
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
 {
-	time_t		curtime;
-	pid_t		pgArchPid;
+	Size		size = 0;
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	size = add_size(size, sizeof(PgArchData));
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
+	return size;
+}
 
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
 
-			PgArchiverMain(0, NULL);
-			break;
-#endif
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
 
-		default:
-			return (int) pgArchPid;
+	if (!found)
+	{
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		PgArch->pgprocno = INVALID_PGPROCNO;
 	}
-
-	/* shouldn't get here */
-	return 0;
 }
 
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
 /*
- * pgarch_forkexec() -
+ *  PgArchIsSuppressed
  *
- * Format up the arglist for, then fork and exec, archive process
+ * Return true if archiver relaunch is suppressed.
+ *
+ * This is a safety valve to protect against continuous respawn attempts if the
+ * archiver is dying immediately at launch. Note that since we will retry to
+ * launch the archiver from the postmaster main loop, we will get another
+ * chance later.
  */
-static pid_t
-pgarch_forkexec(void)
+bool
+PgArchCanRestart(void)
 {
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
+	static time_t last_pgarch_start_time = 0;
+	time_t		curtime = time(NULL);
 
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
+	/*
+	 * allow to launch also for the first time and when something's wrong in
+	 * the time values.
+	 */
+	if (last_pgarch_start_time == 0 ||
+		curtime < last_pgarch_start_time ||
+		(curtime - last_pgarch_start_time) >= PGARCH_RESTART_INTERVAL)
+	{
+		last_pgarch_start_time = curtime;
 
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
+		return true;
+	}
 
-	return postmaster_forkexec(ac, av);
+	return false;
 }
-#endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +177,51 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* We shouldn't be launched unnecessarily. */
+	Assert(XLogArchivingActive());
+
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our pgproc index so that backends can use our latch to wake
+	 * us up while we're sleeping.
+	 */
+	PgArch->pgprocno = MyProc->pgprocno;
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	int			arch_pgprocno = PgArch->pgprocno;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	/*
+	 * We don't acquire ProcArrayLock here.  It's actually fine because
+	 * procLatch isn't ever freed, so we just can potentially set the wrong
+	 * process' (or no process') latch.  Even in that case the archiver will
+	 * be relaunched shortly and will start archiving.
+	 */
+	if (arch_pgprocno != INVALID_PGPROCNO)
+		SetLatch(&ProcGlobal->allProcs[arch_pgprocno].procLatch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +246,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +284,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +306,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +692,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	PgArch->pgprocno = INVALID_PGPROCNO;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..e8af05c04e 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -443,9 +443,10 @@ static void InitPostmasterDeathWatchHandle(void);
  * even during recovery.
  */
 #define PgArchStartupAllowed()	\
-	((XLogArchivingActive() && pmState == PM_RUN) ||	\
-	 (XLogArchivingAlways() &&	\
-	  (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY)))
+	(((XLogArchivingActive() && pmState == PM_RUN) ||			\
+	  (XLogArchivingAlways() &&									  \
+	   (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY))) && \
+	 PgArchCanRestart())
 
 #ifdef EXEC_BACKEND
 
@@ -548,6 +549,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1794,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3009,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3144,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for
+		 * it to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3407,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3613,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3805,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and
+		 * syslogger processes are disregarded since they are not connected to
+		 * shared memory; we also disregard dead_end children here. Walsenders
+		 * and archiver are also disregarded, they will be terminated later
+		 * after writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..1e47a143e1 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,10 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern bool PgArchCanRestart(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_17_24_43_2021_866)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v55 3/3] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 240 ++++++++++-------------
 src/backend/postmaster/postmaster.c      |  81 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  14 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 164 insertions(+), 212 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..07ba989a37 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,101 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	int			pgprocno;		/* pgprocno of archiver process */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
-
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
 {
-	time_t		curtime;
-	pid_t		pgArchPid;
+	Size		size = 0;
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	size = add_size(size, sizeof(PgArchData));
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
+	return size;
+}
 
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
 
-			PgArchiverMain(0, NULL);
-			break;
-#endif
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
 
-		default:
-			return (int) pgArchPid;
+	if (!found)
+	{
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		PgArch->pgprocno = INVALID_PGPROCNO;
 	}
-
-	/* shouldn't get here */
-	return 0;
 }
 
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
 /*
- * pgarch_forkexec() -
+ *  PgArchIsSuppressed
  *
- * Format up the arglist for, then fork and exec, archive process
+ * Return true if archiver relaunch is suppressed.
+ *
+ * This is a safety valve to protect against continuous respawn attempts if the
+ * archiver is dying immediately at launch. Note that since we will retry to
+ * launch the archiver from the postmaster main loop, we will get another
+ * chance later.
  */
-static pid_t
-pgarch_forkexec(void)
+bool
+PgArchCanRestart(void)
 {
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
+	static time_t last_pgarch_start_time = 0;
+	time_t		curtime = time(NULL);
 
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
+	/*
+	 * allow to launch also for the first time and when something's wrong in
+	 * the time values.
+	 */
+	if (last_pgarch_start_time == 0 ||
+		curtime < last_pgarch_start_time ||
+		(curtime - last_pgarch_start_time) >= PGARCH_RESTART_INTERVAL)
+	{
+		last_pgarch_start_time = curtime;
 
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
+		return true;
+	}
 
-	return postmaster_forkexec(ac, av);
+	return false;
 }
-#endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +177,51 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* We shouldn't be launched unnecessarily. */
+	Assert(XLogArchivingActive());
+
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our pgproc index so that backends can use our latch to wake
+	 * us up while we're sleeping.
+	 */
+	PgArch->pgprocno = MyProc->pgprocno;
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	int			arch_pgprocno = PgArch->pgprocno;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	/*
+	 * We don't acquire ProcArrayLock here.  It's actually fine because
+	 * procLatch isn't ever freed, so we just can potentially set the wrong
+	 * process' (or no process') latch.  Even in that case the archiver will
+	 * be relaunched shortly and will start archiving.
+	 */
+	if (arch_pgprocno != INVALID_PGPROCNO)
+		SetLatch(&ProcGlobal->allProcs[arch_pgprocno].procLatch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +246,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +284,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +306,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +692,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	PgArch->pgprocno = INVALID_PGPROCNO;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..e8af05c04e 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -443,9 +443,10 @@ static void InitPostmasterDeathWatchHandle(void);
  * even during recovery.
  */
 #define PgArchStartupAllowed()	\
-	((XLogArchivingActive() && pmState == PM_RUN) ||	\
-	 (XLogArchivingAlways() &&	\
-	  (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY)))
+	(((XLogArchivingActive() && pmState == PM_RUN) ||			\
+	  (XLogArchivingAlways() &&									  \
+	   (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY))) && \
+	 PgArchCanRestart())
 
 #ifdef EXEC_BACKEND
 
@@ -548,6 +549,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1794,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3009,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3144,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for
+		 * it to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3407,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3613,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3805,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and
+		 * syslogger processes are disregarded since they are not connected to
+		 * shared memory; we also disregard dead_end children here. Walsenders
+		 * and archiver are also disregarded, they will be terminated later
+		 * after writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..1e47a143e1 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,10 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern bool PgArchCanRestart(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_17_24_43_2021_866)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v53 3/7] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 227 ++++++++---------------
 src/backend/postmaster/postmaster.c      |  74 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  13 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 137 insertions(+), 218 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..818c9a1f3f 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,70 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	Latch	   *latch;			/* latch to wake the archiver up */
+	slock_t		mutex;			/* locks this struct */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size		size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
+	return size;
+}
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
+	if (!found)
 	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		SpinLockInit(&PgArch->mutex);
+		PgArch->latch = NULL;
 	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
 }
-#endif							/* EXEC_BACKEND */
-
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +146,49 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = MyLatch;
+	SpinLockRelease(&PgArch->mutex);
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	Latch	   *latch;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
+	/* fetching the latch pointer might not be atomic, so use spinlock */
+	SpinLockAcquire(&PgArch->mutex);
+	latch = PgArch->latch;
+	SpinLockRelease(&PgArch->mutex);
 
-	errno = save_errno;
+	if (latch)
+		SetLatch(latch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +213,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +251,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +273,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +659,17 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = NULL;
+	SpinLockRelease(&PgArch->mutex);
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..460e629145 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3143,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3804,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and syslogger
+		 * processes are disregarded since they are not connected to shared
+		 * memory; we also disregard dead_end children here. Walsenders and
+		 * archiver are also disregarded, they will be terminated later after
+		 * writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3911,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5037,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5134,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5188,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5429,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..d053bf1564 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,9 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_09_23_13_2021_947)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v53 3/7] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 227 ++++++++---------------
 src/backend/postmaster/postmaster.c      |  74 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  13 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 137 insertions(+), 218 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..818c9a1f3f 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,70 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	Latch	   *latch;			/* latch to wake the archiver up */
+	slock_t		mutex;			/* locks this struct */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size		size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
+	return size;
+}
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
+	if (!found)
 	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		SpinLockInit(&PgArch->mutex);
+		PgArch->latch = NULL;
 	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
 }
-#endif							/* EXEC_BACKEND */
-
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +146,49 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = MyLatch;
+	SpinLockRelease(&PgArch->mutex);
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	Latch	   *latch;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
+	/* fetching the latch pointer might not be atomic, so use spinlock */
+	SpinLockAcquire(&PgArch->mutex);
+	latch = PgArch->latch;
+	SpinLockRelease(&PgArch->mutex);
 
-	errno = save_errno;
+	if (latch)
+		SetLatch(latch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +213,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +251,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +273,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +659,17 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = NULL;
+	SpinLockRelease(&PgArch->mutex);
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..460e629145 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3143,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3804,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and syslogger
+		 * processes are disregarded since they are not connected to shared
+		 * memory; we also disregard dead_end children here. Walsenders and
+		 * archiver are also disregarded, they will be terminated later after
+		 * writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3911,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5037,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5134,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5188,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5429,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..d053bf1564 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,9 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_09_23_13_2021_947)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v54 3/7] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 241 +++++++++--------------
 src/backend/postmaster/postmaster.c      |  81 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  14 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 160 insertions(+), 217 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..8e572afea3 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,6 +71,12 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	int		pgprocno;				/* pgprocno of archiver process */
+} PgArchData;
+
 
 /* ----------
  * Local data
@@ -80,146 +84,79 @@
  */
 static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size		size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
+
+	return size;
+}
+
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
+
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
+
+	if (!found)
+	{
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		PgArch->pgprocno = INVALID_PGPROCNO;
+	}
+}
 
 /*
- * pgarch_start
+ *  PgArchIsSuppressed
  *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
+ * Return true if archiver relaunch is suppressed.
  *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
+ * This is a safety valve to protect against continuous respawn attempts if the
+ * archiver is dying immediately at launch. Note that since we will retry to
+ * launch the archiver from the postmaster main loop, we will get another
+ * chance later.
  */
-int
-pgarch_start(void)
+bool
+PgArchIsSuppressed(void)
 {
-	time_t		curtime;
-	pid_t		pgArchPid;
+	time_t	curtime = time(NULL);
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+	if ((curtime - last_pgarch_start_time) < PGARCH_RESTART_INTERVAL)
+		return true;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
 	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
+	return false;
 }
-#endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +168,51 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* We shouldn't be launched unnecessarily. */
+	Assert(XLogArchivingActive());
+
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	PgArch->pgprocno = MyProc->pgprocno;
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	int	arch_pgprocno = PgArch->pgprocno;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	/*
+	 * We don't acquire ProcArrayLock here.  It's actually fine because
+	 * procLatch isn't ever freed, so we just can potentially set the wrong
+	 * process' (or no process') latch.  Even in that case the archiver will be
+	 * relaunched shortly and will start archiving.
+	 */
+	if (arch_pgprocno != INVALID_PGPROCNO)
+		SetLatch(&ProcGlobal->allProcs[arch_pgprocno].procLatch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +237,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +275,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +297,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +683,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	PgArch->pgprocno = INVALID_PGPROCNO;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..4f8e364284 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -443,9 +443,10 @@ static void InitPostmasterDeathWatchHandle(void);
  * even during recovery.
  */
 #define PgArchStartupAllowed()	\
-	((XLogArchivingActive() && pmState == PM_RUN) ||	\
-	 (XLogArchivingAlways() &&	\
-	  (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY)))
+	(((XLogArchivingActive() && pmState == PM_RUN) ||	\
+	  (XLogArchivingAlways() &&									\
+	   (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY))) && \
+	 !PgArchIsSuppressed())
 
 #ifdef EXEC_BACKEND
 
@@ -548,6 +549,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1794,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3009,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3144,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3407,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3613,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3805,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and syslogger
+		 * processes are disregarded since they are not connected to shared
+		 * memory; we also disregard dead_end children here. Walsenders and
+		 * archiver are also disregarded, they will be terminated later after
+		 * writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..640692d33e 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,10 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern bool PgArchIsSuppressed(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_13_49_06_2021_682)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v55 3/3] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 240 ++++++++++-------------
 src/backend/postmaster/postmaster.c      |  81 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  14 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 164 insertions(+), 212 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..07ba989a37 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,101 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	int			pgprocno;		/* pgprocno of archiver process */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
-
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
 {
-	time_t		curtime;
-	pid_t		pgArchPid;
+	Size		size = 0;
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	size = add_size(size, sizeof(PgArchData));
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
+	return size;
+}
 
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
 
-			PgArchiverMain(0, NULL);
-			break;
-#endif
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
 
-		default:
-			return (int) pgArchPid;
+	if (!found)
+	{
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		PgArch->pgprocno = INVALID_PGPROCNO;
 	}
-
-	/* shouldn't get here */
-	return 0;
 }
 
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
 /*
- * pgarch_forkexec() -
+ *  PgArchIsSuppressed
  *
- * Format up the arglist for, then fork and exec, archive process
+ * Return true if archiver relaunch is suppressed.
+ *
+ * This is a safety valve to protect against continuous respawn attempts if the
+ * archiver is dying immediately at launch. Note that since we will retry to
+ * launch the archiver from the postmaster main loop, we will get another
+ * chance later.
  */
-static pid_t
-pgarch_forkexec(void)
+bool
+PgArchCanRestart(void)
 {
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
+	static time_t last_pgarch_start_time = 0;
+	time_t		curtime = time(NULL);
 
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
+	/*
+	 * allow to launch also for the first time and when something's wrong in
+	 * the time values.
+	 */
+	if (last_pgarch_start_time == 0 ||
+		curtime < last_pgarch_start_time ||
+		(curtime - last_pgarch_start_time) >= PGARCH_RESTART_INTERVAL)
+	{
+		last_pgarch_start_time = curtime;
 
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
+		return true;
+	}
 
-	return postmaster_forkexec(ac, av);
+	return false;
 }
-#endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +177,51 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* We shouldn't be launched unnecessarily. */
+	Assert(XLogArchivingActive());
+
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our pgproc index so that backends can use our latch to wake
+	 * us up while we're sleeping.
+	 */
+	PgArch->pgprocno = MyProc->pgprocno;
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	int			arch_pgprocno = PgArch->pgprocno;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	/*
+	 * We don't acquire ProcArrayLock here.  It's actually fine because
+	 * procLatch isn't ever freed, so we just can potentially set the wrong
+	 * process' (or no process') latch.  Even in that case the archiver will
+	 * be relaunched shortly and will start archiving.
+	 */
+	if (arch_pgprocno != INVALID_PGPROCNO)
+		SetLatch(&ProcGlobal->allProcs[arch_pgprocno].procLatch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +246,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +284,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +306,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +692,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	PgArch->pgprocno = INVALID_PGPROCNO;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..e8af05c04e 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -443,9 +443,10 @@ static void InitPostmasterDeathWatchHandle(void);
  * even during recovery.
  */
 #define PgArchStartupAllowed()	\
-	((XLogArchivingActive() && pmState == PM_RUN) ||	\
-	 (XLogArchivingAlways() &&	\
-	  (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY)))
+	(((XLogArchivingActive() && pmState == PM_RUN) ||			\
+	  (XLogArchivingAlways() &&									  \
+	   (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY))) && \
+	 PgArchCanRestart())
 
 #ifdef EXEC_BACKEND
 
@@ -548,6 +549,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1794,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3009,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3144,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for
+		 * it to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3407,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3613,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3805,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and
+		 * syslogger processes are disregarded since they are not connected to
+		 * shared memory; we also disregard dead_end children here. Walsenders
+		 * and archiver are also disregarded, they will be terminated later
+		 * after writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..1e47a143e1 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,10 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern bool PgArchCanRestart(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_17_24_43_2021_866)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v53 3/7] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 227 ++++++++---------------
 src/backend/postmaster/postmaster.c      |  74 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  13 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 137 insertions(+), 218 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..818c9a1f3f 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,70 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	Latch	   *latch;			/* latch to wake the archiver up */
+	slock_t		mutex;			/* locks this struct */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size		size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
+	return size;
+}
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
+	if (!found)
 	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		SpinLockInit(&PgArch->mutex);
+		PgArch->latch = NULL;
 	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
 }
-#endif							/* EXEC_BACKEND */
-
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +146,49 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = MyLatch;
+	SpinLockRelease(&PgArch->mutex);
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	Latch	   *latch;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
+	/* fetching the latch pointer might not be atomic, so use spinlock */
+	SpinLockAcquire(&PgArch->mutex);
+	latch = PgArch->latch;
+	SpinLockRelease(&PgArch->mutex);
 
-	errno = save_errno;
+	if (latch)
+		SetLatch(latch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +213,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +251,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +273,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +659,17 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = NULL;
+	SpinLockRelease(&PgArch->mutex);
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..460e629145 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3143,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3804,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and syslogger
+		 * processes are disregarded since they are not connected to shared
+		 * memory; we also disregard dead_end children here. Walsenders and
+		 * archiver are also disregarded, they will be terminated later after
+		 * writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3911,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5037,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5134,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5188,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5429,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..d053bf1564 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,9 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_09_23_13_2021_947)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v54 3/7] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 241 +++++++++--------------
 src/backend/postmaster/postmaster.c      |  81 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  14 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 160 insertions(+), 217 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..8e572afea3 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,6 +71,12 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	int		pgprocno;				/* pgprocno of archiver process */
+} PgArchData;
+
 
 /* ----------
  * Local data
@@ -80,146 +84,79 @@
  */
 static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size		size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
+
+	return size;
+}
+
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
+
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
+
+	if (!found)
+	{
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		PgArch->pgprocno = INVALID_PGPROCNO;
+	}
+}
 
 /*
- * pgarch_start
+ *  PgArchIsSuppressed
  *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
+ * Return true if archiver relaunch is suppressed.
  *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
+ * This is a safety valve to protect against continuous respawn attempts if the
+ * archiver is dying immediately at launch. Note that since we will retry to
+ * launch the archiver from the postmaster main loop, we will get another
+ * chance later.
  */
-int
-pgarch_start(void)
+bool
+PgArchIsSuppressed(void)
 {
-	time_t		curtime;
-	pid_t		pgArchPid;
+	time_t	curtime = time(NULL);
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+	if ((curtime - last_pgarch_start_time) < PGARCH_RESTART_INTERVAL)
+		return true;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
 	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
+	return false;
 }
-#endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +168,51 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* We shouldn't be launched unnecessarily. */
+	Assert(XLogArchivingActive());
+
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	PgArch->pgprocno = MyProc->pgprocno;
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	int	arch_pgprocno = PgArch->pgprocno;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	/*
+	 * We don't acquire ProcArrayLock here.  It's actually fine because
+	 * procLatch isn't ever freed, so we just can potentially set the wrong
+	 * process' (or no process') latch.  Even in that case the archiver will be
+	 * relaunched shortly and will start archiving.
+	 */
+	if (arch_pgprocno != INVALID_PGPROCNO)
+		SetLatch(&ProcGlobal->allProcs[arch_pgprocno].procLatch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +237,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +275,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +297,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +683,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	PgArch->pgprocno = INVALID_PGPROCNO;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..4f8e364284 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -443,9 +443,10 @@ static void InitPostmasterDeathWatchHandle(void);
  * even during recovery.
  */
 #define PgArchStartupAllowed()	\
-	((XLogArchivingActive() && pmState == PM_RUN) ||	\
-	 (XLogArchivingAlways() &&	\
-	  (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY)))
+	(((XLogArchivingActive() && pmState == PM_RUN) ||	\
+	  (XLogArchivingAlways() &&									\
+	   (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY))) && \
+	 !PgArchIsSuppressed())
 
 #ifdef EXEC_BACKEND
 
@@ -548,6 +549,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1794,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3009,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3144,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3407,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3613,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3805,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and syslogger
+		 * processes are disregarded since they are not connected to shared
+		 * memory; we also disregard dead_end children here. Walsenders and
+		 * archiver are also disregarded, they will be terminated later after
+		 * writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..640692d33e 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,10 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern bool PgArchIsSuppressed(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_13_49_06_2021_682)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v55 3/3] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 240 ++++++++++-------------
 src/backend/postmaster/postmaster.c      |  81 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  14 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 164 insertions(+), 212 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..07ba989a37 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,101 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	int			pgprocno;		/* pgprocno of archiver process */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
-
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
 {
-	time_t		curtime;
-	pid_t		pgArchPid;
+	Size		size = 0;
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	size = add_size(size, sizeof(PgArchData));
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
+	return size;
+}
 
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
 
-			PgArchiverMain(0, NULL);
-			break;
-#endif
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
 
-		default:
-			return (int) pgArchPid;
+	if (!found)
+	{
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		PgArch->pgprocno = INVALID_PGPROCNO;
 	}
-
-	/* shouldn't get here */
-	return 0;
 }
 
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
 /*
- * pgarch_forkexec() -
+ *  PgArchIsSuppressed
  *
- * Format up the arglist for, then fork and exec, archive process
+ * Return true if archiver relaunch is suppressed.
+ *
+ * This is a safety valve to protect against continuous respawn attempts if the
+ * archiver is dying immediately at launch. Note that since we will retry to
+ * launch the archiver from the postmaster main loop, we will get another
+ * chance later.
  */
-static pid_t
-pgarch_forkexec(void)
+bool
+PgArchCanRestart(void)
 {
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
+	static time_t last_pgarch_start_time = 0;
+	time_t		curtime = time(NULL);
 
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
+	/*
+	 * allow to launch also for the first time and when something's wrong in
+	 * the time values.
+	 */
+	if (last_pgarch_start_time == 0 ||
+		curtime < last_pgarch_start_time ||
+		(curtime - last_pgarch_start_time) >= PGARCH_RESTART_INTERVAL)
+	{
+		last_pgarch_start_time = curtime;
 
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
+		return true;
+	}
 
-	return postmaster_forkexec(ac, av);
+	return false;
 }
-#endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +177,51 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* We shouldn't be launched unnecessarily. */
+	Assert(XLogArchivingActive());
+
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our pgproc index so that backends can use our latch to wake
+	 * us up while we're sleeping.
+	 */
+	PgArch->pgprocno = MyProc->pgprocno;
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	int			arch_pgprocno = PgArch->pgprocno;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	/*
+	 * We don't acquire ProcArrayLock here.  It's actually fine because
+	 * procLatch isn't ever freed, so we just can potentially set the wrong
+	 * process' (or no process') latch.  Even in that case the archiver will
+	 * be relaunched shortly and will start archiving.
+	 */
+	if (arch_pgprocno != INVALID_PGPROCNO)
+		SetLatch(&ProcGlobal->allProcs[arch_pgprocno].procLatch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +246,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +284,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +306,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +692,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	PgArch->pgprocno = INVALID_PGPROCNO;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..e8af05c04e 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -443,9 +443,10 @@ static void InitPostmasterDeathWatchHandle(void);
  * even during recovery.
  */
 #define PgArchStartupAllowed()	\
-	((XLogArchivingActive() && pmState == PM_RUN) ||	\
-	 (XLogArchivingAlways() &&	\
-	  (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY)))
+	(((XLogArchivingActive() && pmState == PM_RUN) ||			\
+	  (XLogArchivingAlways() &&									  \
+	   (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY))) && \
+	 PgArchCanRestart())
 
 #ifdef EXEC_BACKEND
 
@@ -548,6 +549,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1794,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3009,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3144,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for
+		 * it to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3407,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3613,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3805,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and
+		 * syslogger processes are disregarded since they are not connected to
+		 * shared memory; we also disregard dead_end children here. Walsenders
+		 * and archiver are also disregarded, they will be terminated later
+		 * after writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..1e47a143e1 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,10 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern bool PgArchCanRestart(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_17_24_43_2021_866)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v54 3/7] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 241 +++++++++--------------
 src/backend/postmaster/postmaster.c      |  81 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  14 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 160 insertions(+), 217 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..8e572afea3 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,6 +71,12 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	int		pgprocno;				/* pgprocno of archiver process */
+} PgArchData;
+
 
 /* ----------
  * Local data
@@ -80,146 +84,79 @@
  */
 static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size		size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
+
+	return size;
+}
+
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
+
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
+
+	if (!found)
+	{
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		PgArch->pgprocno = INVALID_PGPROCNO;
+	}
+}
 
 /*
- * pgarch_start
+ *  PgArchIsSuppressed
  *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
+ * Return true if archiver relaunch is suppressed.
  *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
+ * This is a safety valve to protect against continuous respawn attempts if the
+ * archiver is dying immediately at launch. Note that since we will retry to
+ * launch the archiver from the postmaster main loop, we will get another
+ * chance later.
  */
-int
-pgarch_start(void)
+bool
+PgArchIsSuppressed(void)
 {
-	time_t		curtime;
-	pid_t		pgArchPid;
+	time_t	curtime = time(NULL);
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+	if ((curtime - last_pgarch_start_time) < PGARCH_RESTART_INTERVAL)
+		return true;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
 	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
+	return false;
 }
-#endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +168,51 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* We shouldn't be launched unnecessarily. */
+	Assert(XLogArchivingActive());
+
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	PgArch->pgprocno = MyProc->pgprocno;
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	int	arch_pgprocno = PgArch->pgprocno;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	/*
+	 * We don't acquire ProcArrayLock here.  It's actually fine because
+	 * procLatch isn't ever freed, so we just can potentially set the wrong
+	 * process' (or no process') latch.  Even in that case the archiver will be
+	 * relaunched shortly and will start archiving.
+	 */
+	if (arch_pgprocno != INVALID_PGPROCNO)
+		SetLatch(&ProcGlobal->allProcs[arch_pgprocno].procLatch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +237,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +275,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +297,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +683,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	PgArch->pgprocno = INVALID_PGPROCNO;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..4f8e364284 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -443,9 +443,10 @@ static void InitPostmasterDeathWatchHandle(void);
  * even during recovery.
  */
 #define PgArchStartupAllowed()	\
-	((XLogArchivingActive() && pmState == PM_RUN) ||	\
-	 (XLogArchivingAlways() &&	\
-	  (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY)))
+	(((XLogArchivingActive() && pmState == PM_RUN) ||	\
+	  (XLogArchivingAlways() &&									\
+	   (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY))) && \
+	 !PgArchIsSuppressed())
 
 #ifdef EXEC_BACKEND
 
@@ -548,6 +549,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1794,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3009,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3144,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3407,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3613,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3805,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and syslogger
+		 * processes are disregarded since they are not connected to shared
+		 * memory; we also disregard dead_end children here. Walsenders and
+		 * archiver are also disregarded, they will be terminated later after
+		 * writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..640692d33e 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,10 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern bool PgArchIsSuppressed(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_13_49_06_2021_682)----





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* [PATCH v55 3/3] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 240 ++++++++++-------------
 src/backend/postmaster/postmaster.c      |  81 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  14 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 164 insertions(+), 212 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..07ba989a37 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,101 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	int			pgprocno;		/* pgprocno of archiver process */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
-
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
 {
-	time_t		curtime;
-	pid_t		pgArchPid;
+	Size		size = 0;
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	size = add_size(size, sizeof(PgArchData));
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
+	return size;
+}
 
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
 
-			PgArchiverMain(0, NULL);
-			break;
-#endif
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
 
-		default:
-			return (int) pgArchPid;
+	if (!found)
+	{
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		PgArch->pgprocno = INVALID_PGPROCNO;
 	}
-
-	/* shouldn't get here */
-	return 0;
 }
 
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
 /*
- * pgarch_forkexec() -
+ *  PgArchIsSuppressed
  *
- * Format up the arglist for, then fork and exec, archive process
+ * Return true if archiver relaunch is suppressed.
+ *
+ * This is a safety valve to protect against continuous respawn attempts if the
+ * archiver is dying immediately at launch. Note that since we will retry to
+ * launch the archiver from the postmaster main loop, we will get another
+ * chance later.
  */
-static pid_t
-pgarch_forkexec(void)
+bool
+PgArchCanRestart(void)
 {
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
+	static time_t last_pgarch_start_time = 0;
+	time_t		curtime = time(NULL);
 
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
+	/*
+	 * allow to launch also for the first time and when something's wrong in
+	 * the time values.
+	 */
+	if (last_pgarch_start_time == 0 ||
+		curtime < last_pgarch_start_time ||
+		(curtime - last_pgarch_start_time) >= PGARCH_RESTART_INTERVAL)
+	{
+		last_pgarch_start_time = curtime;
 
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
+		return true;
+	}
 
-	return postmaster_forkexec(ac, av);
+	return false;
 }
-#endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +177,51 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* We shouldn't be launched unnecessarily. */
+	Assert(XLogArchivingActive());
+
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our pgproc index so that backends can use our latch to wake
+	 * us up while we're sleeping.
+	 */
+	PgArch->pgprocno = MyProc->pgprocno;
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	int			arch_pgprocno = PgArch->pgprocno;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	/*
+	 * We don't acquire ProcArrayLock here.  It's actually fine because
+	 * procLatch isn't ever freed, so we just can potentially set the wrong
+	 * process' (or no process') latch.  Even in that case the archiver will
+	 * be relaunched shortly and will start archiving.
+	 */
+	if (arch_pgprocno != INVALID_PGPROCNO)
+		SetLatch(&ProcGlobal->allProcs[arch_pgprocno].procLatch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +246,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +284,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +306,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +692,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	PgArch->pgprocno = INVALID_PGPROCNO;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..e8af05c04e 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -443,9 +443,10 @@ static void InitPostmasterDeathWatchHandle(void);
  * even during recovery.
  */
 #define PgArchStartupAllowed()	\
-	((XLogArchivingActive() && pmState == PM_RUN) ||	\
-	 (XLogArchivingAlways() &&	\
-	  (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY)))
+	(((XLogArchivingActive() && pmState == PM_RUN) ||			\
+	  (XLogArchivingAlways() &&									  \
+	   (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY))) && \
+	 PgArchCanRestart())
 
 #ifdef EXEC_BACKEND
 
@@ -548,6 +549,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1794,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3009,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3144,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for
+		 * it to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3407,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3613,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3805,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and
+		 * syslogger processes are disregarded since they are not connected to
+		 * shared memory; we also disregard dead_end children here. Walsenders
+		 * and archiver are also disregarded, they will be terminated later
+		 * after writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..1e47a143e1 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,10 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern bool PgArchCanRestart(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_17_24_43_2021_866)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v53 3/7] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 227 ++++++++---------------
 src/backend/postmaster/postmaster.c      |  74 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  13 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 137 insertions(+), 218 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..818c9a1f3f 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,70 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	Latch	   *latch;			/* latch to wake the archiver up */
+	slock_t		mutex;			/* locks this struct */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size		size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
+	return size;
+}
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
+	if (!found)
 	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		SpinLockInit(&PgArch->mutex);
+		PgArch->latch = NULL;
 	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
 }
-#endif							/* EXEC_BACKEND */
-
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +146,49 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = MyLatch;
+	SpinLockRelease(&PgArch->mutex);
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	Latch	   *latch;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
+	/* fetching the latch pointer might not be atomic, so use spinlock */
+	SpinLockAcquire(&PgArch->mutex);
+	latch = PgArch->latch;
+	SpinLockRelease(&PgArch->mutex);
 
-	errno = save_errno;
+	if (latch)
+		SetLatch(latch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +213,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +251,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +273,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +659,17 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = NULL;
+	SpinLockRelease(&PgArch->mutex);
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..460e629145 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3143,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3804,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and syslogger
+		 * processes are disregarded since they are not connected to shared
+		 * memory; we also disregard dead_end children here. Walsenders and
+		 * archiver are also disregarded, they will be terminated later after
+		 * writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3911,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5037,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5134,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5188,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5429,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..d053bf1564 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,9 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_09_23_13_2021_947)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v53 3/7] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 227 ++++++++---------------
 src/backend/postmaster/postmaster.c      |  74 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  13 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 137 insertions(+), 218 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..818c9a1f3f 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,70 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	Latch	   *latch;			/* latch to wake the archiver up */
+	slock_t		mutex;			/* locks this struct */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size		size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
+	return size;
+}
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
+	if (!found)
 	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		SpinLockInit(&PgArch->mutex);
+		PgArch->latch = NULL;
 	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
 }
-#endif							/* EXEC_BACKEND */
-
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +146,49 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = MyLatch;
+	SpinLockRelease(&PgArch->mutex);
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	Latch	   *latch;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
+	/* fetching the latch pointer might not be atomic, so use spinlock */
+	SpinLockAcquire(&PgArch->mutex);
+	latch = PgArch->latch;
+	SpinLockRelease(&PgArch->mutex);
 
-	errno = save_errno;
+	if (latch)
+		SetLatch(latch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +213,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +251,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +273,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +659,17 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = NULL;
+	SpinLockRelease(&PgArch->mutex);
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..460e629145 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3143,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3804,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and syslogger
+		 * processes are disregarded since they are not connected to shared
+		 * memory; we also disregard dead_end children here. Walsenders and
+		 * archiver are also disregarded, they will be terminated later after
+		 * writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3911,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5037,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5134,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5188,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5429,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..d053bf1564 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,9 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_09_23_13_2021_947)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v54 3/7] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 241 +++++++++--------------
 src/backend/postmaster/postmaster.c      |  81 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  14 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 160 insertions(+), 217 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..8e572afea3 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,6 +71,12 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	int		pgprocno;				/* pgprocno of archiver process */
+} PgArchData;
+
 
 /* ----------
  * Local data
@@ -80,146 +84,79 @@
  */
 static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size		size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
+
+	return size;
+}
+
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
+
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
+
+	if (!found)
+	{
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		PgArch->pgprocno = INVALID_PGPROCNO;
+	}
+}
 
 /*
- * pgarch_start
+ *  PgArchIsSuppressed
  *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
+ * Return true if archiver relaunch is suppressed.
  *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
+ * This is a safety valve to protect against continuous respawn attempts if the
+ * archiver is dying immediately at launch. Note that since we will retry to
+ * launch the archiver from the postmaster main loop, we will get another
+ * chance later.
  */
-int
-pgarch_start(void)
+bool
+PgArchIsSuppressed(void)
 {
-	time_t		curtime;
-	pid_t		pgArchPid;
+	time_t	curtime = time(NULL);
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+	if ((curtime - last_pgarch_start_time) < PGARCH_RESTART_INTERVAL)
+		return true;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
 	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
+	return false;
 }
-#endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +168,51 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* We shouldn't be launched unnecessarily. */
+	Assert(XLogArchivingActive());
+
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	PgArch->pgprocno = MyProc->pgprocno;
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	int	arch_pgprocno = PgArch->pgprocno;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	/*
+	 * We don't acquire ProcArrayLock here.  It's actually fine because
+	 * procLatch isn't ever freed, so we just can potentially set the wrong
+	 * process' (or no process') latch.  Even in that case the archiver will be
+	 * relaunched shortly and will start archiving.
+	 */
+	if (arch_pgprocno != INVALID_PGPROCNO)
+		SetLatch(&ProcGlobal->allProcs[arch_pgprocno].procLatch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +237,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +275,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +297,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +683,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	PgArch->pgprocno = INVALID_PGPROCNO;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..4f8e364284 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -443,9 +443,10 @@ static void InitPostmasterDeathWatchHandle(void);
  * even during recovery.
  */
 #define PgArchStartupAllowed()	\
-	((XLogArchivingActive() && pmState == PM_RUN) ||	\
-	 (XLogArchivingAlways() &&	\
-	  (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY)))
+	(((XLogArchivingActive() && pmState == PM_RUN) ||	\
+	  (XLogArchivingAlways() &&									\
+	   (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY))) && \
+	 !PgArchIsSuppressed())
 
 #ifdef EXEC_BACKEND
 
@@ -548,6 +549,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1794,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3009,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3144,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3407,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3613,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3805,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and syslogger
+		 * processes are disregarded since they are not connected to shared
+		 * memory; we also disregard dead_end children here. Walsenders and
+		 * archiver are also disregarded, they will be terminated later after
+		 * writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..640692d33e 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,10 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern bool PgArchIsSuppressed(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_13_49_06_2021_682)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v55 3/3] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 240 ++++++++++-------------
 src/backend/postmaster/postmaster.c      |  81 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  14 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 164 insertions(+), 212 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..07ba989a37 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,101 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	int			pgprocno;		/* pgprocno of archiver process */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
-
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
 {
-	time_t		curtime;
-	pid_t		pgArchPid;
+	Size		size = 0;
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	size = add_size(size, sizeof(PgArchData));
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
+	return size;
+}
 
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
 
-			PgArchiverMain(0, NULL);
-			break;
-#endif
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
 
-		default:
-			return (int) pgArchPid;
+	if (!found)
+	{
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		PgArch->pgprocno = INVALID_PGPROCNO;
 	}
-
-	/* shouldn't get here */
-	return 0;
 }
 
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
 /*
- * pgarch_forkexec() -
+ *  PgArchIsSuppressed
  *
- * Format up the arglist for, then fork and exec, archive process
+ * Return true if archiver relaunch is suppressed.
+ *
+ * This is a safety valve to protect against continuous respawn attempts if the
+ * archiver is dying immediately at launch. Note that since we will retry to
+ * launch the archiver from the postmaster main loop, we will get another
+ * chance later.
  */
-static pid_t
-pgarch_forkexec(void)
+bool
+PgArchCanRestart(void)
 {
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
+	static time_t last_pgarch_start_time = 0;
+	time_t		curtime = time(NULL);
 
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
+	/*
+	 * allow to launch also for the first time and when something's wrong in
+	 * the time values.
+	 */
+	if (last_pgarch_start_time == 0 ||
+		curtime < last_pgarch_start_time ||
+		(curtime - last_pgarch_start_time) >= PGARCH_RESTART_INTERVAL)
+	{
+		last_pgarch_start_time = curtime;
 
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
+		return true;
+	}
 
-	return postmaster_forkexec(ac, av);
+	return false;
 }
-#endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +177,51 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* We shouldn't be launched unnecessarily. */
+	Assert(XLogArchivingActive());
+
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our pgproc index so that backends can use our latch to wake
+	 * us up while we're sleeping.
+	 */
+	PgArch->pgprocno = MyProc->pgprocno;
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	int			arch_pgprocno = PgArch->pgprocno;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	/*
+	 * We don't acquire ProcArrayLock here.  It's actually fine because
+	 * procLatch isn't ever freed, so we just can potentially set the wrong
+	 * process' (or no process') latch.  Even in that case the archiver will
+	 * be relaunched shortly and will start archiving.
+	 */
+	if (arch_pgprocno != INVALID_PGPROCNO)
+		SetLatch(&ProcGlobal->allProcs[arch_pgprocno].procLatch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +246,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +284,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +306,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +692,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	PgArch->pgprocno = INVALID_PGPROCNO;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..e8af05c04e 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -443,9 +443,10 @@ static void InitPostmasterDeathWatchHandle(void);
  * even during recovery.
  */
 #define PgArchStartupAllowed()	\
-	((XLogArchivingActive() && pmState == PM_RUN) ||	\
-	 (XLogArchivingAlways() &&	\
-	  (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY)))
+	(((XLogArchivingActive() && pmState == PM_RUN) ||			\
+	  (XLogArchivingAlways() &&									  \
+	   (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY))) && \
+	 PgArchCanRestart())
 
 #ifdef EXEC_BACKEND
 
@@ -548,6 +549,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1794,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3009,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3144,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for
+		 * it to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3407,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3613,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3805,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and
+		 * syslogger processes are disregarded since they are not connected to
+		 * shared memory; we also disregard dead_end children here. Walsenders
+		 * and archiver are also disregarded, they will be terminated later
+		 * after writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..1e47a143e1 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,10 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern bool PgArchCanRestart(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_17_24_43_2021_866)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v54 3/7] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 241 +++++++++--------------
 src/backend/postmaster/postmaster.c      |  81 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  14 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 160 insertions(+), 217 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..8e572afea3 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,6 +71,12 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	int		pgprocno;				/* pgprocno of archiver process */
+} PgArchData;
+
 
 /* ----------
  * Local data
@@ -80,146 +84,79 @@
  */
 static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size		size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
+
+	return size;
+}
+
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
+
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
+
+	if (!found)
+	{
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		PgArch->pgprocno = INVALID_PGPROCNO;
+	}
+}
 
 /*
- * pgarch_start
+ *  PgArchIsSuppressed
  *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
+ * Return true if archiver relaunch is suppressed.
  *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
+ * This is a safety valve to protect against continuous respawn attempts if the
+ * archiver is dying immediately at launch. Note that since we will retry to
+ * launch the archiver from the postmaster main loop, we will get another
+ * chance later.
  */
-int
-pgarch_start(void)
+bool
+PgArchIsSuppressed(void)
 {
-	time_t		curtime;
-	pid_t		pgArchPid;
+	time_t	curtime = time(NULL);
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+	if ((curtime - last_pgarch_start_time) < PGARCH_RESTART_INTERVAL)
+		return true;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
 	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
+	return false;
 }
-#endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +168,51 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* We shouldn't be launched unnecessarily. */
+	Assert(XLogArchivingActive());
+
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	PgArch->pgprocno = MyProc->pgprocno;
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	int	arch_pgprocno = PgArch->pgprocno;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	/*
+	 * We don't acquire ProcArrayLock here.  It's actually fine because
+	 * procLatch isn't ever freed, so we just can potentially set the wrong
+	 * process' (or no process') latch.  Even in that case the archiver will be
+	 * relaunched shortly and will start archiving.
+	 */
+	if (arch_pgprocno != INVALID_PGPROCNO)
+		SetLatch(&ProcGlobal->allProcs[arch_pgprocno].procLatch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +237,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +275,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +297,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +683,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	PgArch->pgprocno = INVALID_PGPROCNO;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..4f8e364284 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -443,9 +443,10 @@ static void InitPostmasterDeathWatchHandle(void);
  * even during recovery.
  */
 #define PgArchStartupAllowed()	\
-	((XLogArchivingActive() && pmState == PM_RUN) ||	\
-	 (XLogArchivingAlways() &&	\
-	  (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY)))
+	(((XLogArchivingActive() && pmState == PM_RUN) ||	\
+	  (XLogArchivingAlways() &&									\
+	   (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY))) && \
+	 !PgArchIsSuppressed())
 
 #ifdef EXEC_BACKEND
 
@@ -548,6 +549,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1794,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3009,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3144,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3407,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3613,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3805,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and syslogger
+		 * processes are disregarded since they are not connected to shared
+		 * memory; we also disregard dead_end children here. Walsenders and
+		 * archiver are also disregarded, they will be terminated later after
+		 * writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..640692d33e 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,10 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern bool PgArchIsSuppressed(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_13_49_06_2021_682)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v55 3/3] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 240 ++++++++++-------------
 src/backend/postmaster/postmaster.c      |  81 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  14 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 164 insertions(+), 212 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..07ba989a37 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,101 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	int			pgprocno;		/* pgprocno of archiver process */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
-
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
 {
-	time_t		curtime;
-	pid_t		pgArchPid;
+	Size		size = 0;
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	size = add_size(size, sizeof(PgArchData));
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
+	return size;
+}
 
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
 
-			PgArchiverMain(0, NULL);
-			break;
-#endif
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
 
-		default:
-			return (int) pgArchPid;
+	if (!found)
+	{
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		PgArch->pgprocno = INVALID_PGPROCNO;
 	}
-
-	/* shouldn't get here */
-	return 0;
 }
 
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
 /*
- * pgarch_forkexec() -
+ *  PgArchIsSuppressed
  *
- * Format up the arglist for, then fork and exec, archive process
+ * Return true if archiver relaunch is suppressed.
+ *
+ * This is a safety valve to protect against continuous respawn attempts if the
+ * archiver is dying immediately at launch. Note that since we will retry to
+ * launch the archiver from the postmaster main loop, we will get another
+ * chance later.
  */
-static pid_t
-pgarch_forkexec(void)
+bool
+PgArchCanRestart(void)
 {
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
+	static time_t last_pgarch_start_time = 0;
+	time_t		curtime = time(NULL);
 
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
+	/*
+	 * allow to launch also for the first time and when something's wrong in
+	 * the time values.
+	 */
+	if (last_pgarch_start_time == 0 ||
+		curtime < last_pgarch_start_time ||
+		(curtime - last_pgarch_start_time) >= PGARCH_RESTART_INTERVAL)
+	{
+		last_pgarch_start_time = curtime;
 
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
+		return true;
+	}
 
-	return postmaster_forkexec(ac, av);
+	return false;
 }
-#endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +177,51 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* We shouldn't be launched unnecessarily. */
+	Assert(XLogArchivingActive());
+
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our pgproc index so that backends can use our latch to wake
+	 * us up while we're sleeping.
+	 */
+	PgArch->pgprocno = MyProc->pgprocno;
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	int			arch_pgprocno = PgArch->pgprocno;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	/*
+	 * We don't acquire ProcArrayLock here.  It's actually fine because
+	 * procLatch isn't ever freed, so we just can potentially set the wrong
+	 * process' (or no process') latch.  Even in that case the archiver will
+	 * be relaunched shortly and will start archiving.
+	 */
+	if (arch_pgprocno != INVALID_PGPROCNO)
+		SetLatch(&ProcGlobal->allProcs[arch_pgprocno].procLatch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +246,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +284,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +306,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +692,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	PgArch->pgprocno = INVALID_PGPROCNO;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..e8af05c04e 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -443,9 +443,10 @@ static void InitPostmasterDeathWatchHandle(void);
  * even during recovery.
  */
 #define PgArchStartupAllowed()	\
-	((XLogArchivingActive() && pmState == PM_RUN) ||	\
-	 (XLogArchivingAlways() &&	\
-	  (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY)))
+	(((XLogArchivingActive() && pmState == PM_RUN) ||			\
+	  (XLogArchivingAlways() &&									  \
+	   (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY))) && \
+	 PgArchCanRestart())
 
 #ifdef EXEC_BACKEND
 
@@ -548,6 +549,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1794,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3009,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3144,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for
+		 * it to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3407,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3613,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3805,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and
+		 * syslogger processes are disregarded since they are not connected to
+		 * shared memory; we also disregard dead_end children here. Walsenders
+		 * and archiver are also disregarded, they will be terminated later
+		 * after writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..1e47a143e1 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,10 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern bool PgArchCanRestart(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_17_24_43_2021_866)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v53 3/7] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 227 ++++++++---------------
 src/backend/postmaster/postmaster.c      |  74 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  13 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 137 insertions(+), 218 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..818c9a1f3f 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,70 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	Latch	   *latch;			/* latch to wake the archiver up */
+	slock_t		mutex;			/* locks this struct */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size		size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
+	return size;
+}
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
+	if (!found)
 	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		SpinLockInit(&PgArch->mutex);
+		PgArch->latch = NULL;
 	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
 }
-#endif							/* EXEC_BACKEND */
-
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +146,49 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = MyLatch;
+	SpinLockRelease(&PgArch->mutex);
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	Latch	   *latch;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
+	/* fetching the latch pointer might not be atomic, so use spinlock */
+	SpinLockAcquire(&PgArch->mutex);
+	latch = PgArch->latch;
+	SpinLockRelease(&PgArch->mutex);
 
-	errno = save_errno;
+	if (latch)
+		SetLatch(latch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +213,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +251,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +273,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +659,17 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = NULL;
+	SpinLockRelease(&PgArch->mutex);
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..460e629145 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3143,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3804,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and syslogger
+		 * processes are disregarded since they are not connected to shared
+		 * memory; we also disregard dead_end children here. Walsenders and
+		 * archiver are also disregarded, they will be terminated later after
+		 * writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3911,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5037,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5134,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5188,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5429,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..d053bf1564 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,9 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_09_23_13_2021_947)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v53 3/7] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 227 ++++++++---------------
 src/backend/postmaster/postmaster.c      |  74 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  13 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 137 insertions(+), 218 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..818c9a1f3f 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,70 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	Latch	   *latch;			/* latch to wake the archiver up */
+	slock_t		mutex;			/* locks this struct */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size		size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
+	return size;
+}
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
+	if (!found)
 	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		SpinLockInit(&PgArch->mutex);
+		PgArch->latch = NULL;
 	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
 }
-#endif							/* EXEC_BACKEND */
-
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +146,49 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = MyLatch;
+	SpinLockRelease(&PgArch->mutex);
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	Latch	   *latch;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
+	/* fetching the latch pointer might not be atomic, so use spinlock */
+	SpinLockAcquire(&PgArch->mutex);
+	latch = PgArch->latch;
+	SpinLockRelease(&PgArch->mutex);
 
-	errno = save_errno;
+	if (latch)
+		SetLatch(latch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +213,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +251,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +273,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +659,17 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = NULL;
+	SpinLockRelease(&PgArch->mutex);
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..460e629145 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3143,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3804,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and syslogger
+		 * processes are disregarded since they are not connected to shared
+		 * memory; we also disregard dead_end children here. Walsenders and
+		 * archiver are also disregarded, they will be terminated later after
+		 * writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3911,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5037,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5134,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5188,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5429,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..d053bf1564 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,9 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_09_23_13_2021_947)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v54 3/7] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 241 +++++++++--------------
 src/backend/postmaster/postmaster.c      |  81 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  14 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 160 insertions(+), 217 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..8e572afea3 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,6 +71,12 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	int		pgprocno;				/* pgprocno of archiver process */
+} PgArchData;
+
 
 /* ----------
  * Local data
@@ -80,146 +84,79 @@
  */
 static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size		size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
+
+	return size;
+}
+
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
+
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
+
+	if (!found)
+	{
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		PgArch->pgprocno = INVALID_PGPROCNO;
+	}
+}
 
 /*
- * pgarch_start
+ *  PgArchIsSuppressed
  *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
+ * Return true if archiver relaunch is suppressed.
  *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
+ * This is a safety valve to protect against continuous respawn attempts if the
+ * archiver is dying immediately at launch. Note that since we will retry to
+ * launch the archiver from the postmaster main loop, we will get another
+ * chance later.
  */
-int
-pgarch_start(void)
+bool
+PgArchIsSuppressed(void)
 {
-	time_t		curtime;
-	pid_t		pgArchPid;
+	time_t	curtime = time(NULL);
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+	if ((curtime - last_pgarch_start_time) < PGARCH_RESTART_INTERVAL)
+		return true;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
 	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
+	return false;
 }
-#endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +168,51 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* We shouldn't be launched unnecessarily. */
+	Assert(XLogArchivingActive());
+
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	PgArch->pgprocno = MyProc->pgprocno;
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	int	arch_pgprocno = PgArch->pgprocno;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	/*
+	 * We don't acquire ProcArrayLock here.  It's actually fine because
+	 * procLatch isn't ever freed, so we just can potentially set the wrong
+	 * process' (or no process') latch.  Even in that case the archiver will be
+	 * relaunched shortly and will start archiving.
+	 */
+	if (arch_pgprocno != INVALID_PGPROCNO)
+		SetLatch(&ProcGlobal->allProcs[arch_pgprocno].procLatch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +237,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +275,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +297,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +683,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	PgArch->pgprocno = INVALID_PGPROCNO;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..4f8e364284 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -443,9 +443,10 @@ static void InitPostmasterDeathWatchHandle(void);
  * even during recovery.
  */
 #define PgArchStartupAllowed()	\
-	((XLogArchivingActive() && pmState == PM_RUN) ||	\
-	 (XLogArchivingAlways() &&	\
-	  (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY)))
+	(((XLogArchivingActive() && pmState == PM_RUN) ||	\
+	  (XLogArchivingAlways() &&									\
+	   (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY))) && \
+	 !PgArchIsSuppressed())
 
 #ifdef EXEC_BACKEND
 
@@ -548,6 +549,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1794,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3009,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3144,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3407,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3613,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3805,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and syslogger
+		 * processes are disregarded since they are not connected to shared
+		 * memory; we also disregard dead_end children here. Walsenders and
+		 * archiver are also disregarded, they will be terminated later after
+		 * writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..640692d33e 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,10 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern bool PgArchIsSuppressed(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_13_49_06_2021_682)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v55 3/3] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 240 ++++++++++-------------
 src/backend/postmaster/postmaster.c      |  81 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  14 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 164 insertions(+), 212 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..07ba989a37 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,101 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	int			pgprocno;		/* pgprocno of archiver process */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
-
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
 {
-	time_t		curtime;
-	pid_t		pgArchPid;
+	Size		size = 0;
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	size = add_size(size, sizeof(PgArchData));
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
+	return size;
+}
 
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
 
-			PgArchiverMain(0, NULL);
-			break;
-#endif
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
 
-		default:
-			return (int) pgArchPid;
+	if (!found)
+	{
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		PgArch->pgprocno = INVALID_PGPROCNO;
 	}
-
-	/* shouldn't get here */
-	return 0;
 }
 
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
 /*
- * pgarch_forkexec() -
+ *  PgArchIsSuppressed
  *
- * Format up the arglist for, then fork and exec, archive process
+ * Return true if archiver relaunch is suppressed.
+ *
+ * This is a safety valve to protect against continuous respawn attempts if the
+ * archiver is dying immediately at launch. Note that since we will retry to
+ * launch the archiver from the postmaster main loop, we will get another
+ * chance later.
  */
-static pid_t
-pgarch_forkexec(void)
+bool
+PgArchCanRestart(void)
 {
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
+	static time_t last_pgarch_start_time = 0;
+	time_t		curtime = time(NULL);
 
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
+	/*
+	 * allow to launch also for the first time and when something's wrong in
+	 * the time values.
+	 */
+	if (last_pgarch_start_time == 0 ||
+		curtime < last_pgarch_start_time ||
+		(curtime - last_pgarch_start_time) >= PGARCH_RESTART_INTERVAL)
+	{
+		last_pgarch_start_time = curtime;
 
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
+		return true;
+	}
 
-	return postmaster_forkexec(ac, av);
+	return false;
 }
-#endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +177,51 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* We shouldn't be launched unnecessarily. */
+	Assert(XLogArchivingActive());
+
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our pgproc index so that backends can use our latch to wake
+	 * us up while we're sleeping.
+	 */
+	PgArch->pgprocno = MyProc->pgprocno;
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	int			arch_pgprocno = PgArch->pgprocno;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	/*
+	 * We don't acquire ProcArrayLock here.  It's actually fine because
+	 * procLatch isn't ever freed, so we just can potentially set the wrong
+	 * process' (or no process') latch.  Even in that case the archiver will
+	 * be relaunched shortly and will start archiving.
+	 */
+	if (arch_pgprocno != INVALID_PGPROCNO)
+		SetLatch(&ProcGlobal->allProcs[arch_pgprocno].procLatch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +246,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +284,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +306,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +692,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	PgArch->pgprocno = INVALID_PGPROCNO;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..e8af05c04e 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -443,9 +443,10 @@ static void InitPostmasterDeathWatchHandle(void);
  * even during recovery.
  */
 #define PgArchStartupAllowed()	\
-	((XLogArchivingActive() && pmState == PM_RUN) ||	\
-	 (XLogArchivingAlways() &&	\
-	  (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY)))
+	(((XLogArchivingActive() && pmState == PM_RUN) ||			\
+	  (XLogArchivingAlways() &&									  \
+	   (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY))) && \
+	 PgArchCanRestart())
 
 #ifdef EXEC_BACKEND
 
@@ -548,6 +549,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1794,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3009,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3144,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for
+		 * it to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3407,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3613,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3805,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and
+		 * syslogger processes are disregarded since they are not connected to
+		 * shared memory; we also disregard dead_end children here. Walsenders
+		 * and archiver are also disregarded, they will be terminated later
+		 * after writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..1e47a143e1 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,10 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern bool PgArchCanRestart(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_17_24_43_2021_866)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v53 3/7] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 227 ++++++++---------------
 src/backend/postmaster/postmaster.c      |  74 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  13 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 137 insertions(+), 218 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..818c9a1f3f 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,70 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	Latch	   *latch;			/* latch to wake the archiver up */
+	slock_t		mutex;			/* locks this struct */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size		size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
+	return size;
+}
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
+	if (!found)
 	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		SpinLockInit(&PgArch->mutex);
+		PgArch->latch = NULL;
 	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
 }
-#endif							/* EXEC_BACKEND */
-
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +146,49 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = MyLatch;
+	SpinLockRelease(&PgArch->mutex);
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	Latch	   *latch;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
+	/* fetching the latch pointer might not be atomic, so use spinlock */
+	SpinLockAcquire(&PgArch->mutex);
+	latch = PgArch->latch;
+	SpinLockRelease(&PgArch->mutex);
 
-	errno = save_errno;
+	if (latch)
+		SetLatch(latch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +213,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +251,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +273,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +659,17 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = NULL;
+	SpinLockRelease(&PgArch->mutex);
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..460e629145 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3143,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3804,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and syslogger
+		 * processes are disregarded since they are not connected to shared
+		 * memory; we also disregard dead_end children here. Walsenders and
+		 * archiver are also disregarded, they will be terminated later after
+		 * writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3911,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5037,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5134,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5188,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5429,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..d053bf1564 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,9 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_09_23_13_2021_947)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v53 3/7] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 227 ++++++++---------------
 src/backend/postmaster/postmaster.c      |  74 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  13 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 137 insertions(+), 218 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..818c9a1f3f 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,70 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	Latch	   *latch;			/* latch to wake the archiver up */
+	slock_t		mutex;			/* locks this struct */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size		size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
+	return size;
+}
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
+	if (!found)
 	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		SpinLockInit(&PgArch->mutex);
+		PgArch->latch = NULL;
 	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
 }
-#endif							/* EXEC_BACKEND */
-
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +146,49 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = MyLatch;
+	SpinLockRelease(&PgArch->mutex);
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	Latch	   *latch;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
+	/* fetching the latch pointer might not be atomic, so use spinlock */
+	SpinLockAcquire(&PgArch->mutex);
+	latch = PgArch->latch;
+	SpinLockRelease(&PgArch->mutex);
 
-	errno = save_errno;
+	if (latch)
+		SetLatch(latch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +213,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +251,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +273,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +659,17 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = NULL;
+	SpinLockRelease(&PgArch->mutex);
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..460e629145 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3143,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3804,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and syslogger
+		 * processes are disregarded since they are not connected to shared
+		 * memory; we also disregard dead_end children here. Walsenders and
+		 * archiver are also disregarded, they will be terminated later after
+		 * writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3911,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5037,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5134,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5188,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5429,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..d053bf1564 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,9 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_09_23_13_2021_947)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v54 3/7] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 241 +++++++++--------------
 src/backend/postmaster/postmaster.c      |  81 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  14 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 160 insertions(+), 217 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..8e572afea3 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,6 +71,12 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	int		pgprocno;				/* pgprocno of archiver process */
+} PgArchData;
+
 
 /* ----------
  * Local data
@@ -80,146 +84,79 @@
  */
 static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size		size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
+
+	return size;
+}
+
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
+
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
+
+	if (!found)
+	{
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		PgArch->pgprocno = INVALID_PGPROCNO;
+	}
+}
 
 /*
- * pgarch_start
+ *  PgArchIsSuppressed
  *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
+ * Return true if archiver relaunch is suppressed.
  *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
+ * This is a safety valve to protect against continuous respawn attempts if the
+ * archiver is dying immediately at launch. Note that since we will retry to
+ * launch the archiver from the postmaster main loop, we will get another
+ * chance later.
  */
-int
-pgarch_start(void)
+bool
+PgArchIsSuppressed(void)
 {
-	time_t		curtime;
-	pid_t		pgArchPid;
+	time_t	curtime = time(NULL);
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+	if ((curtime - last_pgarch_start_time) < PGARCH_RESTART_INTERVAL)
+		return true;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
 	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
+	return false;
 }
-#endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +168,51 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* We shouldn't be launched unnecessarily. */
+	Assert(XLogArchivingActive());
+
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	PgArch->pgprocno = MyProc->pgprocno;
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	int	arch_pgprocno = PgArch->pgprocno;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	/*
+	 * We don't acquire ProcArrayLock here.  It's actually fine because
+	 * procLatch isn't ever freed, so we just can potentially set the wrong
+	 * process' (or no process') latch.  Even in that case the archiver will be
+	 * relaunched shortly and will start archiving.
+	 */
+	if (arch_pgprocno != INVALID_PGPROCNO)
+		SetLatch(&ProcGlobal->allProcs[arch_pgprocno].procLatch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +237,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +275,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +297,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +683,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	PgArch->pgprocno = INVALID_PGPROCNO;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..4f8e364284 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -443,9 +443,10 @@ static void InitPostmasterDeathWatchHandle(void);
  * even during recovery.
  */
 #define PgArchStartupAllowed()	\
-	((XLogArchivingActive() && pmState == PM_RUN) ||	\
-	 (XLogArchivingAlways() &&	\
-	  (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY)))
+	(((XLogArchivingActive() && pmState == PM_RUN) ||	\
+	  (XLogArchivingAlways() &&									\
+	   (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY))) && \
+	 !PgArchIsSuppressed())
 
 #ifdef EXEC_BACKEND
 
@@ -548,6 +549,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1794,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3009,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3144,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3407,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3613,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3805,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and syslogger
+		 * processes are disregarded since they are not connected to shared
+		 * memory; we also disregard dead_end children here. Walsenders and
+		 * archiver are also disregarded, they will be terminated later after
+		 * writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..640692d33e 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,10 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern bool PgArchIsSuppressed(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_13_49_06_2021_682)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v55 3/3] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 240 ++++++++++-------------
 src/backend/postmaster/postmaster.c      |  81 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  14 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 164 insertions(+), 212 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..07ba989a37 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,101 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	int			pgprocno;		/* pgprocno of archiver process */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
-
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
 {
-	time_t		curtime;
-	pid_t		pgArchPid;
+	Size		size = 0;
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	size = add_size(size, sizeof(PgArchData));
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
+	return size;
+}
 
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
 
-			PgArchiverMain(0, NULL);
-			break;
-#endif
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
 
-		default:
-			return (int) pgArchPid;
+	if (!found)
+	{
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		PgArch->pgprocno = INVALID_PGPROCNO;
 	}
-
-	/* shouldn't get here */
-	return 0;
 }
 
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
 /*
- * pgarch_forkexec() -
+ *  PgArchIsSuppressed
  *
- * Format up the arglist for, then fork and exec, archive process
+ * Return true if archiver relaunch is suppressed.
+ *
+ * This is a safety valve to protect against continuous respawn attempts if the
+ * archiver is dying immediately at launch. Note that since we will retry to
+ * launch the archiver from the postmaster main loop, we will get another
+ * chance later.
  */
-static pid_t
-pgarch_forkexec(void)
+bool
+PgArchCanRestart(void)
 {
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
+	static time_t last_pgarch_start_time = 0;
+	time_t		curtime = time(NULL);
 
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
+	/*
+	 * allow to launch also for the first time and when something's wrong in
+	 * the time values.
+	 */
+	if (last_pgarch_start_time == 0 ||
+		curtime < last_pgarch_start_time ||
+		(curtime - last_pgarch_start_time) >= PGARCH_RESTART_INTERVAL)
+	{
+		last_pgarch_start_time = curtime;
 
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
+		return true;
+	}
 
-	return postmaster_forkexec(ac, av);
+	return false;
 }
-#endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +177,51 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* We shouldn't be launched unnecessarily. */
+	Assert(XLogArchivingActive());
+
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our pgproc index so that backends can use our latch to wake
+	 * us up while we're sleeping.
+	 */
+	PgArch->pgprocno = MyProc->pgprocno;
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	int			arch_pgprocno = PgArch->pgprocno;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	/*
+	 * We don't acquire ProcArrayLock here.  It's actually fine because
+	 * procLatch isn't ever freed, so we just can potentially set the wrong
+	 * process' (or no process') latch.  Even in that case the archiver will
+	 * be relaunched shortly and will start archiving.
+	 */
+	if (arch_pgprocno != INVALID_PGPROCNO)
+		SetLatch(&ProcGlobal->allProcs[arch_pgprocno].procLatch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +246,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +284,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +306,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +692,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	PgArch->pgprocno = INVALID_PGPROCNO;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..e8af05c04e 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -443,9 +443,10 @@ static void InitPostmasterDeathWatchHandle(void);
  * even during recovery.
  */
 #define PgArchStartupAllowed()	\
-	((XLogArchivingActive() && pmState == PM_RUN) ||	\
-	 (XLogArchivingAlways() &&	\
-	  (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY)))
+	(((XLogArchivingActive() && pmState == PM_RUN) ||			\
+	  (XLogArchivingAlways() &&									  \
+	   (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY))) && \
+	 PgArchCanRestart())
 
 #ifdef EXEC_BACKEND
 
@@ -548,6 +549,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1794,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3009,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3144,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for
+		 * it to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3407,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3613,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3805,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and
+		 * syslogger processes are disregarded since they are not connected to
+		 * shared memory; we also disregard dead_end children here. Walsenders
+		 * and archiver are also disregarded, they will be terminated later
+		 * after writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..1e47a143e1 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,10 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern bool PgArchCanRestart(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_17_24_43_2021_866)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v54 3/7] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 241 +++++++++--------------
 src/backend/postmaster/postmaster.c      |  81 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  14 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 160 insertions(+), 217 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..8e572afea3 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,6 +71,12 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	int		pgprocno;				/* pgprocno of archiver process */
+} PgArchData;
+
 
 /* ----------
  * Local data
@@ -80,146 +84,79 @@
  */
 static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size		size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
+
+	return size;
+}
+
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
+
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
+
+	if (!found)
+	{
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		PgArch->pgprocno = INVALID_PGPROCNO;
+	}
+}
 
 /*
- * pgarch_start
+ *  PgArchIsSuppressed
  *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
+ * Return true if archiver relaunch is suppressed.
  *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
+ * This is a safety valve to protect against continuous respawn attempts if the
+ * archiver is dying immediately at launch. Note that since we will retry to
+ * launch the archiver from the postmaster main loop, we will get another
+ * chance later.
  */
-int
-pgarch_start(void)
+bool
+PgArchIsSuppressed(void)
 {
-	time_t		curtime;
-	pid_t		pgArchPid;
+	time_t	curtime = time(NULL);
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+	if ((curtime - last_pgarch_start_time) < PGARCH_RESTART_INTERVAL)
+		return true;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
 	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
+	return false;
 }
-#endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +168,51 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* We shouldn't be launched unnecessarily. */
+	Assert(XLogArchivingActive());
+
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	PgArch->pgprocno = MyProc->pgprocno;
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	int	arch_pgprocno = PgArch->pgprocno;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	/*
+	 * We don't acquire ProcArrayLock here.  It's actually fine because
+	 * procLatch isn't ever freed, so we just can potentially set the wrong
+	 * process' (or no process') latch.  Even in that case the archiver will be
+	 * relaunched shortly and will start archiving.
+	 */
+	if (arch_pgprocno != INVALID_PGPROCNO)
+		SetLatch(&ProcGlobal->allProcs[arch_pgprocno].procLatch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +237,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +275,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +297,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +683,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	PgArch->pgprocno = INVALID_PGPROCNO;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..4f8e364284 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -443,9 +443,10 @@ static void InitPostmasterDeathWatchHandle(void);
  * even during recovery.
  */
 #define PgArchStartupAllowed()	\
-	((XLogArchivingActive() && pmState == PM_RUN) ||	\
-	 (XLogArchivingAlways() &&	\
-	  (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY)))
+	(((XLogArchivingActive() && pmState == PM_RUN) ||	\
+	  (XLogArchivingAlways() &&									\
+	   (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY))) && \
+	 !PgArchIsSuppressed())
 
 #ifdef EXEC_BACKEND
 
@@ -548,6 +549,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1794,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3009,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3144,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3407,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3613,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3805,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and syslogger
+		 * processes are disregarded since they are not connected to shared
+		 * memory; we also disregard dead_end children here. Walsenders and
+		 * archiver are also disregarded, they will be terminated later after
+		 * writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..640692d33e 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,10 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern bool PgArchIsSuppressed(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_13_49_06_2021_682)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v53 3/7] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 227 ++++++++---------------
 src/backend/postmaster/postmaster.c      |  74 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  13 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 137 insertions(+), 218 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..818c9a1f3f 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,70 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	Latch	   *latch;			/* latch to wake the archiver up */
+	slock_t		mutex;			/* locks this struct */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size		size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
+	return size;
+}
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
+	if (!found)
 	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		SpinLockInit(&PgArch->mutex);
+		PgArch->latch = NULL;
 	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
 }
-#endif							/* EXEC_BACKEND */
-
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +146,49 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = MyLatch;
+	SpinLockRelease(&PgArch->mutex);
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	Latch	   *latch;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
+	/* fetching the latch pointer might not be atomic, so use spinlock */
+	SpinLockAcquire(&PgArch->mutex);
+	latch = PgArch->latch;
+	SpinLockRelease(&PgArch->mutex);
 
-	errno = save_errno;
+	if (latch)
+		SetLatch(latch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +213,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +251,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +273,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +659,17 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = NULL;
+	SpinLockRelease(&PgArch->mutex);
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..460e629145 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3143,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3804,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and syslogger
+		 * processes are disregarded since they are not connected to shared
+		 * memory; we also disregard dead_end children here. Walsenders and
+		 * archiver are also disregarded, they will be terminated later after
+		 * writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3911,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5037,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5134,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5188,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5429,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..d053bf1564 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,9 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_09_23_13_2021_947)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v53 3/7] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 227 ++++++++---------------
 src/backend/postmaster/postmaster.c      |  74 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  13 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 137 insertions(+), 218 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..818c9a1f3f 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,70 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	Latch	   *latch;			/* latch to wake the archiver up */
+	slock_t		mutex;			/* locks this struct */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size		size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
+	return size;
+}
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
+	if (!found)
 	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		SpinLockInit(&PgArch->mutex);
+		PgArch->latch = NULL;
 	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
 }
-#endif							/* EXEC_BACKEND */
-
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +146,49 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = MyLatch;
+	SpinLockRelease(&PgArch->mutex);
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	Latch	   *latch;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
+	/* fetching the latch pointer might not be atomic, so use spinlock */
+	SpinLockAcquire(&PgArch->mutex);
+	latch = PgArch->latch;
+	SpinLockRelease(&PgArch->mutex);
 
-	errno = save_errno;
+	if (latch)
+		SetLatch(latch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +213,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +251,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +273,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +659,17 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = NULL;
+	SpinLockRelease(&PgArch->mutex);
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..460e629145 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3143,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3804,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and syslogger
+		 * processes are disregarded since they are not connected to shared
+		 * memory; we also disregard dead_end children here. Walsenders and
+		 * archiver are also disregarded, they will be terminated later after
+		 * writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3911,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5037,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5134,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5188,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5429,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..d053bf1564 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,9 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_09_23_13_2021_947)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v54 3/7] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 241 +++++++++--------------
 src/backend/postmaster/postmaster.c      |  81 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  14 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 160 insertions(+), 217 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..8e572afea3 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,6 +71,12 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	int		pgprocno;				/* pgprocno of archiver process */
+} PgArchData;
+
 
 /* ----------
  * Local data
@@ -80,146 +84,79 @@
  */
 static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size		size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
+
+	return size;
+}
+
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
+
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
+
+	if (!found)
+	{
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		PgArch->pgprocno = INVALID_PGPROCNO;
+	}
+}
 
 /*
- * pgarch_start
+ *  PgArchIsSuppressed
  *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
+ * Return true if archiver relaunch is suppressed.
  *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
+ * This is a safety valve to protect against continuous respawn attempts if the
+ * archiver is dying immediately at launch. Note that since we will retry to
+ * launch the archiver from the postmaster main loop, we will get another
+ * chance later.
  */
-int
-pgarch_start(void)
+bool
+PgArchIsSuppressed(void)
 {
-	time_t		curtime;
-	pid_t		pgArchPid;
+	time_t	curtime = time(NULL);
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+	if ((curtime - last_pgarch_start_time) < PGARCH_RESTART_INTERVAL)
+		return true;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
 	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
+	return false;
 }
-#endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +168,51 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* We shouldn't be launched unnecessarily. */
+	Assert(XLogArchivingActive());
+
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	PgArch->pgprocno = MyProc->pgprocno;
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	int	arch_pgprocno = PgArch->pgprocno;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	/*
+	 * We don't acquire ProcArrayLock here.  It's actually fine because
+	 * procLatch isn't ever freed, so we just can potentially set the wrong
+	 * process' (or no process') latch.  Even in that case the archiver will be
+	 * relaunched shortly and will start archiving.
+	 */
+	if (arch_pgprocno != INVALID_PGPROCNO)
+		SetLatch(&ProcGlobal->allProcs[arch_pgprocno].procLatch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +237,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +275,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +297,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +683,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	PgArch->pgprocno = INVALID_PGPROCNO;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..4f8e364284 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -443,9 +443,10 @@ static void InitPostmasterDeathWatchHandle(void);
  * even during recovery.
  */
 #define PgArchStartupAllowed()	\
-	((XLogArchivingActive() && pmState == PM_RUN) ||	\
-	 (XLogArchivingAlways() &&	\
-	  (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY)))
+	(((XLogArchivingActive() && pmState == PM_RUN) ||	\
+	  (XLogArchivingAlways() &&									\
+	   (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY))) && \
+	 !PgArchIsSuppressed())
 
 #ifdef EXEC_BACKEND
 
@@ -548,6 +549,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1794,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3009,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3144,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3407,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3613,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3805,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and syslogger
+		 * processes are disregarded since they are not connected to shared
+		 * memory; we also disregard dead_end children here. Walsenders and
+		 * archiver are also disregarded, they will be terminated later after
+		 * writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..640692d33e 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,10 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern bool PgArchIsSuppressed(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_13_49_06_2021_682)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v55 3/3] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 240 ++++++++++-------------
 src/backend/postmaster/postmaster.c      |  81 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  14 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 164 insertions(+), 212 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..07ba989a37 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,101 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	int			pgprocno;		/* pgprocno of archiver process */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
-
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
 {
-	time_t		curtime;
-	pid_t		pgArchPid;
+	Size		size = 0;
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	size = add_size(size, sizeof(PgArchData));
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
+	return size;
+}
 
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
 
-			PgArchiverMain(0, NULL);
-			break;
-#endif
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
 
-		default:
-			return (int) pgArchPid;
+	if (!found)
+	{
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		PgArch->pgprocno = INVALID_PGPROCNO;
 	}
-
-	/* shouldn't get here */
-	return 0;
 }
 
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
 /*
- * pgarch_forkexec() -
+ *  PgArchIsSuppressed
  *
- * Format up the arglist for, then fork and exec, archive process
+ * Return true if archiver relaunch is suppressed.
+ *
+ * This is a safety valve to protect against continuous respawn attempts if the
+ * archiver is dying immediately at launch. Note that since we will retry to
+ * launch the archiver from the postmaster main loop, we will get another
+ * chance later.
  */
-static pid_t
-pgarch_forkexec(void)
+bool
+PgArchCanRestart(void)
 {
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
+	static time_t last_pgarch_start_time = 0;
+	time_t		curtime = time(NULL);
 
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
+	/*
+	 * allow to launch also for the first time and when something's wrong in
+	 * the time values.
+	 */
+	if (last_pgarch_start_time == 0 ||
+		curtime < last_pgarch_start_time ||
+		(curtime - last_pgarch_start_time) >= PGARCH_RESTART_INTERVAL)
+	{
+		last_pgarch_start_time = curtime;
 
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
+		return true;
+	}
 
-	return postmaster_forkexec(ac, av);
+	return false;
 }
-#endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +177,51 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* We shouldn't be launched unnecessarily. */
+	Assert(XLogArchivingActive());
+
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our pgproc index so that backends can use our latch to wake
+	 * us up while we're sleeping.
+	 */
+	PgArch->pgprocno = MyProc->pgprocno;
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	int			arch_pgprocno = PgArch->pgprocno;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	/*
+	 * We don't acquire ProcArrayLock here.  It's actually fine because
+	 * procLatch isn't ever freed, so we just can potentially set the wrong
+	 * process' (or no process') latch.  Even in that case the archiver will
+	 * be relaunched shortly and will start archiving.
+	 */
+	if (arch_pgprocno != INVALID_PGPROCNO)
+		SetLatch(&ProcGlobal->allProcs[arch_pgprocno].procLatch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +246,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +284,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +306,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +692,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	PgArch->pgprocno = INVALID_PGPROCNO;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..e8af05c04e 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -443,9 +443,10 @@ static void InitPostmasterDeathWatchHandle(void);
  * even during recovery.
  */
 #define PgArchStartupAllowed()	\
-	((XLogArchivingActive() && pmState == PM_RUN) ||	\
-	 (XLogArchivingAlways() &&	\
-	  (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY)))
+	(((XLogArchivingActive() && pmState == PM_RUN) ||			\
+	  (XLogArchivingAlways() &&									  \
+	   (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY))) && \
+	 PgArchCanRestart())
 
 #ifdef EXEC_BACKEND
 
@@ -548,6 +549,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1794,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3009,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3144,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for
+		 * it to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3407,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3613,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3805,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and
+		 * syslogger processes are disregarded since they are not connected to
+		 * shared memory; we also disregard dead_end children here. Walsenders
+		 * and archiver are also disregarded, they will be terminated later
+		 * after writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..1e47a143e1 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,10 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern bool PgArchCanRestart(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_17_24_43_2021_866)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v54 3/7] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 241 +++++++++--------------
 src/backend/postmaster/postmaster.c      |  81 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  14 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 160 insertions(+), 217 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..8e572afea3 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,6 +71,12 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	int		pgprocno;				/* pgprocno of archiver process */
+} PgArchData;
+
 
 /* ----------
  * Local data
@@ -80,146 +84,79 @@
  */
 static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size		size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
+
+	return size;
+}
+
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
+
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
+
+	if (!found)
+	{
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		PgArch->pgprocno = INVALID_PGPROCNO;
+	}
+}
 
 /*
- * pgarch_start
+ *  PgArchIsSuppressed
  *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
+ * Return true if archiver relaunch is suppressed.
  *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
+ * This is a safety valve to protect against continuous respawn attempts if the
+ * archiver is dying immediately at launch. Note that since we will retry to
+ * launch the archiver from the postmaster main loop, we will get another
+ * chance later.
  */
-int
-pgarch_start(void)
+bool
+PgArchIsSuppressed(void)
 {
-	time_t		curtime;
-	pid_t		pgArchPid;
+	time_t	curtime = time(NULL);
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+	if ((curtime - last_pgarch_start_time) < PGARCH_RESTART_INTERVAL)
+		return true;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
 	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
+	return false;
 }
-#endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +168,51 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* We shouldn't be launched unnecessarily. */
+	Assert(XLogArchivingActive());
+
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	PgArch->pgprocno = MyProc->pgprocno;
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	int	arch_pgprocno = PgArch->pgprocno;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	/*
+	 * We don't acquire ProcArrayLock here.  It's actually fine because
+	 * procLatch isn't ever freed, so we just can potentially set the wrong
+	 * process' (or no process') latch.  Even in that case the archiver will be
+	 * relaunched shortly and will start archiving.
+	 */
+	if (arch_pgprocno != INVALID_PGPROCNO)
+		SetLatch(&ProcGlobal->allProcs[arch_pgprocno].procLatch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +237,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +275,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +297,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +683,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	PgArch->pgprocno = INVALID_PGPROCNO;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..4f8e364284 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -443,9 +443,10 @@ static void InitPostmasterDeathWatchHandle(void);
  * even during recovery.
  */
 #define PgArchStartupAllowed()	\
-	((XLogArchivingActive() && pmState == PM_RUN) ||	\
-	 (XLogArchivingAlways() &&	\
-	  (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY)))
+	(((XLogArchivingActive() && pmState == PM_RUN) ||	\
+	  (XLogArchivingAlways() &&									\
+	   (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY))) && \
+	 !PgArchIsSuppressed())
 
 #ifdef EXEC_BACKEND
 
@@ -548,6 +549,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1794,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3009,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3144,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3407,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3613,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3805,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and syslogger
+		 * processes are disregarded since they are not connected to shared
+		 * memory; we also disregard dead_end children here. Walsenders and
+		 * archiver are also disregarded, they will be terminated later after
+		 * writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..640692d33e 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,10 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern bool PgArchIsSuppressed(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_13_49_06_2021_682)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v55 3/3] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 240 ++++++++++-------------
 src/backend/postmaster/postmaster.c      |  81 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  14 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 164 insertions(+), 212 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..07ba989a37 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,101 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	int			pgprocno;		/* pgprocno of archiver process */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
-
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
 {
-	time_t		curtime;
-	pid_t		pgArchPid;
+	Size		size = 0;
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	size = add_size(size, sizeof(PgArchData));
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
+	return size;
+}
 
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
 
-			PgArchiverMain(0, NULL);
-			break;
-#endif
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
 
-		default:
-			return (int) pgArchPid;
+	if (!found)
+	{
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		PgArch->pgprocno = INVALID_PGPROCNO;
 	}
-
-	/* shouldn't get here */
-	return 0;
 }
 
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
 /*
- * pgarch_forkexec() -
+ *  PgArchIsSuppressed
  *
- * Format up the arglist for, then fork and exec, archive process
+ * Return true if archiver relaunch is suppressed.
+ *
+ * This is a safety valve to protect against continuous respawn attempts if the
+ * archiver is dying immediately at launch. Note that since we will retry to
+ * launch the archiver from the postmaster main loop, we will get another
+ * chance later.
  */
-static pid_t
-pgarch_forkexec(void)
+bool
+PgArchCanRestart(void)
 {
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
+	static time_t last_pgarch_start_time = 0;
+	time_t		curtime = time(NULL);
 
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
+	/*
+	 * allow to launch also for the first time and when something's wrong in
+	 * the time values.
+	 */
+	if (last_pgarch_start_time == 0 ||
+		curtime < last_pgarch_start_time ||
+		(curtime - last_pgarch_start_time) >= PGARCH_RESTART_INTERVAL)
+	{
+		last_pgarch_start_time = curtime;
 
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
+		return true;
+	}
 
-	return postmaster_forkexec(ac, av);
+	return false;
 }
-#endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +177,51 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* We shouldn't be launched unnecessarily. */
+	Assert(XLogArchivingActive());
+
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our pgproc index so that backends can use our latch to wake
+	 * us up while we're sleeping.
+	 */
+	PgArch->pgprocno = MyProc->pgprocno;
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	int			arch_pgprocno = PgArch->pgprocno;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	/*
+	 * We don't acquire ProcArrayLock here.  It's actually fine because
+	 * procLatch isn't ever freed, so we just can potentially set the wrong
+	 * process' (or no process') latch.  Even in that case the archiver will
+	 * be relaunched shortly and will start archiving.
+	 */
+	if (arch_pgprocno != INVALID_PGPROCNO)
+		SetLatch(&ProcGlobal->allProcs[arch_pgprocno].procLatch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +246,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +284,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +306,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +692,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	PgArch->pgprocno = INVALID_PGPROCNO;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..e8af05c04e 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -443,9 +443,10 @@ static void InitPostmasterDeathWatchHandle(void);
  * even during recovery.
  */
 #define PgArchStartupAllowed()	\
-	((XLogArchivingActive() && pmState == PM_RUN) ||	\
-	 (XLogArchivingAlways() &&	\
-	  (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY)))
+	(((XLogArchivingActive() && pmState == PM_RUN) ||			\
+	  (XLogArchivingAlways() &&									  \
+	   (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY))) && \
+	 PgArchCanRestart())
 
 #ifdef EXEC_BACKEND
 
@@ -548,6 +549,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1794,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3009,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3144,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for
+		 * it to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3407,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3613,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3805,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and
+		 * syslogger processes are disregarded since they are not connected to
+		 * shared memory; we also disregard dead_end children here. Walsenders
+		 * and archiver are also disregarded, they will be terminated later
+		 * after writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..1e47a143e1 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,10 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern bool PgArchCanRestart(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_17_24_43_2021_866)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v53 3/7] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 227 ++++++++---------------
 src/backend/postmaster/postmaster.c      |  74 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  13 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 137 insertions(+), 218 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..818c9a1f3f 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,70 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	Latch	   *latch;			/* latch to wake the archiver up */
+	slock_t		mutex;			/* locks this struct */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size		size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
+	return size;
+}
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
+	if (!found)
 	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		SpinLockInit(&PgArch->mutex);
+		PgArch->latch = NULL;
 	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
 }
-#endif							/* EXEC_BACKEND */
-
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +146,49 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = MyLatch;
+	SpinLockRelease(&PgArch->mutex);
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	Latch	   *latch;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
+	/* fetching the latch pointer might not be atomic, so use spinlock */
+	SpinLockAcquire(&PgArch->mutex);
+	latch = PgArch->latch;
+	SpinLockRelease(&PgArch->mutex);
 
-	errno = save_errno;
+	if (latch)
+		SetLatch(latch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +213,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +251,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +273,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +659,17 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = NULL;
+	SpinLockRelease(&PgArch->mutex);
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..460e629145 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3143,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3804,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and syslogger
+		 * processes are disregarded since they are not connected to shared
+		 * memory; we also disregard dead_end children here. Walsenders and
+		 * archiver are also disregarded, they will be terminated later after
+		 * writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3911,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5037,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5134,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5188,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5429,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..d053bf1564 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,9 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_09_23_13_2021_947)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v54 3/7] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 241 +++++++++--------------
 src/backend/postmaster/postmaster.c      |  81 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  14 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 160 insertions(+), 217 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..8e572afea3 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,6 +71,12 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	int		pgprocno;				/* pgprocno of archiver process */
+} PgArchData;
+
 
 /* ----------
  * Local data
@@ -80,146 +84,79 @@
  */
 static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size		size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
+
+	return size;
+}
+
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
+
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
+
+	if (!found)
+	{
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		PgArch->pgprocno = INVALID_PGPROCNO;
+	}
+}
 
 /*
- * pgarch_start
+ *  PgArchIsSuppressed
  *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
+ * Return true if archiver relaunch is suppressed.
  *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
+ * This is a safety valve to protect against continuous respawn attempts if the
+ * archiver is dying immediately at launch. Note that since we will retry to
+ * launch the archiver from the postmaster main loop, we will get another
+ * chance later.
  */
-int
-pgarch_start(void)
+bool
+PgArchIsSuppressed(void)
 {
-	time_t		curtime;
-	pid_t		pgArchPid;
+	time_t	curtime = time(NULL);
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+	if ((curtime - last_pgarch_start_time) < PGARCH_RESTART_INTERVAL)
+		return true;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
 	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
+	return false;
 }
-#endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +168,51 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* We shouldn't be launched unnecessarily. */
+	Assert(XLogArchivingActive());
+
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	PgArch->pgprocno = MyProc->pgprocno;
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	int	arch_pgprocno = PgArch->pgprocno;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	/*
+	 * We don't acquire ProcArrayLock here.  It's actually fine because
+	 * procLatch isn't ever freed, so we just can potentially set the wrong
+	 * process' (or no process') latch.  Even in that case the archiver will be
+	 * relaunched shortly and will start archiving.
+	 */
+	if (arch_pgprocno != INVALID_PGPROCNO)
+		SetLatch(&ProcGlobal->allProcs[arch_pgprocno].procLatch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +237,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +275,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +297,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +683,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	PgArch->pgprocno = INVALID_PGPROCNO;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..4f8e364284 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -443,9 +443,10 @@ static void InitPostmasterDeathWatchHandle(void);
  * even during recovery.
  */
 #define PgArchStartupAllowed()	\
-	((XLogArchivingActive() && pmState == PM_RUN) ||	\
-	 (XLogArchivingAlways() &&	\
-	  (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY)))
+	(((XLogArchivingActive() && pmState == PM_RUN) ||	\
+	  (XLogArchivingAlways() &&									\
+	   (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY))) && \
+	 !PgArchIsSuppressed())
 
 #ifdef EXEC_BACKEND
 
@@ -548,6 +549,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1794,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3009,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3144,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3407,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3613,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3805,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and syslogger
+		 * processes are disregarded since they are not connected to shared
+		 * memory; we also disregard dead_end children here. Walsenders and
+		 * archiver are also disregarded, they will be terminated later after
+		 * writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..640692d33e 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,10 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern bool PgArchIsSuppressed(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_13_49_06_2021_682)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v53 3/7] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 227 ++++++++---------------
 src/backend/postmaster/postmaster.c      |  74 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  13 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 137 insertions(+), 218 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..818c9a1f3f 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,70 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	Latch	   *latch;			/* latch to wake the archiver up */
+	slock_t		mutex;			/* locks this struct */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size		size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
+	return size;
+}
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
+	if (!found)
 	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		SpinLockInit(&PgArch->mutex);
+		PgArch->latch = NULL;
 	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
 }
-#endif							/* EXEC_BACKEND */
-
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +146,49 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = MyLatch;
+	SpinLockRelease(&PgArch->mutex);
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	Latch	   *latch;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
+	/* fetching the latch pointer might not be atomic, so use spinlock */
+	SpinLockAcquire(&PgArch->mutex);
+	latch = PgArch->latch;
+	SpinLockRelease(&PgArch->mutex);
 
-	errno = save_errno;
+	if (latch)
+		SetLatch(latch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +213,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +251,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +273,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +659,17 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = NULL;
+	SpinLockRelease(&PgArch->mutex);
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..460e629145 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3143,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3804,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and syslogger
+		 * processes are disregarded since they are not connected to shared
+		 * memory; we also disregard dead_end children here. Walsenders and
+		 * archiver are also disregarded, they will be terminated later after
+		 * writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3911,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5037,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5134,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5188,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5429,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..d053bf1564 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,9 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_09_23_13_2021_947)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v54 3/7] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 241 +++++++++--------------
 src/backend/postmaster/postmaster.c      |  81 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  14 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 160 insertions(+), 217 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..8e572afea3 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,6 +71,12 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	int		pgprocno;				/* pgprocno of archiver process */
+} PgArchData;
+
 
 /* ----------
  * Local data
@@ -80,146 +84,79 @@
  */
 static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size		size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
+
+	return size;
+}
+
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
+
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
+
+	if (!found)
+	{
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		PgArch->pgprocno = INVALID_PGPROCNO;
+	}
+}
 
 /*
- * pgarch_start
+ *  PgArchIsSuppressed
  *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
+ * Return true if archiver relaunch is suppressed.
  *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
+ * This is a safety valve to protect against continuous respawn attempts if the
+ * archiver is dying immediately at launch. Note that since we will retry to
+ * launch the archiver from the postmaster main loop, we will get another
+ * chance later.
  */
-int
-pgarch_start(void)
+bool
+PgArchIsSuppressed(void)
 {
-	time_t		curtime;
-	pid_t		pgArchPid;
+	time_t	curtime = time(NULL);
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+	if ((curtime - last_pgarch_start_time) < PGARCH_RESTART_INTERVAL)
+		return true;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
 	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
+	return false;
 }
-#endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +168,51 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* We shouldn't be launched unnecessarily. */
+	Assert(XLogArchivingActive());
+
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	PgArch->pgprocno = MyProc->pgprocno;
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	int	arch_pgprocno = PgArch->pgprocno;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	/*
+	 * We don't acquire ProcArrayLock here.  It's actually fine because
+	 * procLatch isn't ever freed, so we just can potentially set the wrong
+	 * process' (or no process') latch.  Even in that case the archiver will be
+	 * relaunched shortly and will start archiving.
+	 */
+	if (arch_pgprocno != INVALID_PGPROCNO)
+		SetLatch(&ProcGlobal->allProcs[arch_pgprocno].procLatch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +237,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +275,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +297,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +683,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	PgArch->pgprocno = INVALID_PGPROCNO;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..4f8e364284 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -443,9 +443,10 @@ static void InitPostmasterDeathWatchHandle(void);
  * even during recovery.
  */
 #define PgArchStartupAllowed()	\
-	((XLogArchivingActive() && pmState == PM_RUN) ||	\
-	 (XLogArchivingAlways() &&	\
-	  (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY)))
+	(((XLogArchivingActive() && pmState == PM_RUN) ||	\
+	  (XLogArchivingAlways() &&									\
+	   (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY))) && \
+	 !PgArchIsSuppressed())
 
 #ifdef EXEC_BACKEND
 
@@ -548,6 +549,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1794,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3009,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3144,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3407,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3613,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3805,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and syslogger
+		 * processes are disregarded since they are not connected to shared
+		 * memory; we also disregard dead_end children here. Walsenders and
+		 * archiver are also disregarded, they will be terminated later after
+		 * writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..640692d33e 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,10 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern bool PgArchIsSuppressed(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_13_49_06_2021_682)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v55 3/3] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 240 ++++++++++-------------
 src/backend/postmaster/postmaster.c      |  81 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  14 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 164 insertions(+), 212 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..07ba989a37 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,101 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	int			pgprocno;		/* pgprocno of archiver process */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
-
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
 {
-	time_t		curtime;
-	pid_t		pgArchPid;
+	Size		size = 0;
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	size = add_size(size, sizeof(PgArchData));
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
+	return size;
+}
 
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
 
-			PgArchiverMain(0, NULL);
-			break;
-#endif
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
 
-		default:
-			return (int) pgArchPid;
+	if (!found)
+	{
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		PgArch->pgprocno = INVALID_PGPROCNO;
 	}
-
-	/* shouldn't get here */
-	return 0;
 }
 
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
 /*
- * pgarch_forkexec() -
+ *  PgArchIsSuppressed
  *
- * Format up the arglist for, then fork and exec, archive process
+ * Return true if archiver relaunch is suppressed.
+ *
+ * This is a safety valve to protect against continuous respawn attempts if the
+ * archiver is dying immediately at launch. Note that since we will retry to
+ * launch the archiver from the postmaster main loop, we will get another
+ * chance later.
  */
-static pid_t
-pgarch_forkexec(void)
+bool
+PgArchCanRestart(void)
 {
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
+	static time_t last_pgarch_start_time = 0;
+	time_t		curtime = time(NULL);
 
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
+	/*
+	 * allow to launch also for the first time and when something's wrong in
+	 * the time values.
+	 */
+	if (last_pgarch_start_time == 0 ||
+		curtime < last_pgarch_start_time ||
+		(curtime - last_pgarch_start_time) >= PGARCH_RESTART_INTERVAL)
+	{
+		last_pgarch_start_time = curtime;
 
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
+		return true;
+	}
 
-	return postmaster_forkexec(ac, av);
+	return false;
 }
-#endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +177,51 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* We shouldn't be launched unnecessarily. */
+	Assert(XLogArchivingActive());
+
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our pgproc index so that backends can use our latch to wake
+	 * us up while we're sleeping.
+	 */
+	PgArch->pgprocno = MyProc->pgprocno;
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	int			arch_pgprocno = PgArch->pgprocno;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	/*
+	 * We don't acquire ProcArrayLock here.  It's actually fine because
+	 * procLatch isn't ever freed, so we just can potentially set the wrong
+	 * process' (or no process') latch.  Even in that case the archiver will
+	 * be relaunched shortly and will start archiving.
+	 */
+	if (arch_pgprocno != INVALID_PGPROCNO)
+		SetLatch(&ProcGlobal->allProcs[arch_pgprocno].procLatch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +246,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +284,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +306,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +692,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	PgArch->pgprocno = INVALID_PGPROCNO;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..e8af05c04e 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -443,9 +443,10 @@ static void InitPostmasterDeathWatchHandle(void);
  * even during recovery.
  */
 #define PgArchStartupAllowed()	\
-	((XLogArchivingActive() && pmState == PM_RUN) ||	\
-	 (XLogArchivingAlways() &&	\
-	  (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY)))
+	(((XLogArchivingActive() && pmState == PM_RUN) ||			\
+	  (XLogArchivingAlways() &&									  \
+	   (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY))) && \
+	 PgArchCanRestart())
 
 #ifdef EXEC_BACKEND
 
@@ -548,6 +549,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1794,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3009,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3144,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for
+		 * it to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3407,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3613,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3805,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and
+		 * syslogger processes are disregarded since they are not connected to
+		 * shared memory; we also disregard dead_end children here. Walsenders
+		 * and archiver are also disregarded, they will be terminated later
+		 * after writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..1e47a143e1 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,10 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern bool PgArchCanRestart(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_17_24_43_2021_866)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v55 3/3] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 240 ++++++++++-------------
 src/backend/postmaster/postmaster.c      |  81 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  14 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 164 insertions(+), 212 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..07ba989a37 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,101 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	int			pgprocno;		/* pgprocno of archiver process */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
-
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
 {
-	time_t		curtime;
-	pid_t		pgArchPid;
+	Size		size = 0;
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	size = add_size(size, sizeof(PgArchData));
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
+	return size;
+}
 
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
 
-			PgArchiverMain(0, NULL);
-			break;
-#endif
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
 
-		default:
-			return (int) pgArchPid;
+	if (!found)
+	{
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		PgArch->pgprocno = INVALID_PGPROCNO;
 	}
-
-	/* shouldn't get here */
-	return 0;
 }
 
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
 /*
- * pgarch_forkexec() -
+ *  PgArchIsSuppressed
  *
- * Format up the arglist for, then fork and exec, archive process
+ * Return true if archiver relaunch is suppressed.
+ *
+ * This is a safety valve to protect against continuous respawn attempts if the
+ * archiver is dying immediately at launch. Note that since we will retry to
+ * launch the archiver from the postmaster main loop, we will get another
+ * chance later.
  */
-static pid_t
-pgarch_forkexec(void)
+bool
+PgArchCanRestart(void)
 {
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
+	static time_t last_pgarch_start_time = 0;
+	time_t		curtime = time(NULL);
 
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
+	/*
+	 * allow to launch also for the first time and when something's wrong in
+	 * the time values.
+	 */
+	if (last_pgarch_start_time == 0 ||
+		curtime < last_pgarch_start_time ||
+		(curtime - last_pgarch_start_time) >= PGARCH_RESTART_INTERVAL)
+	{
+		last_pgarch_start_time = curtime;
 
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
+		return true;
+	}
 
-	return postmaster_forkexec(ac, av);
+	return false;
 }
-#endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +177,51 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* We shouldn't be launched unnecessarily. */
+	Assert(XLogArchivingActive());
+
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our pgproc index so that backends can use our latch to wake
+	 * us up while we're sleeping.
+	 */
+	PgArch->pgprocno = MyProc->pgprocno;
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	int			arch_pgprocno = PgArch->pgprocno;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	/*
+	 * We don't acquire ProcArrayLock here.  It's actually fine because
+	 * procLatch isn't ever freed, so we just can potentially set the wrong
+	 * process' (or no process') latch.  Even in that case the archiver will
+	 * be relaunched shortly and will start archiving.
+	 */
+	if (arch_pgprocno != INVALID_PGPROCNO)
+		SetLatch(&ProcGlobal->allProcs[arch_pgprocno].procLatch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +246,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +284,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +306,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +692,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	PgArch->pgprocno = INVALID_PGPROCNO;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..e8af05c04e 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -443,9 +443,10 @@ static void InitPostmasterDeathWatchHandle(void);
  * even during recovery.
  */
 #define PgArchStartupAllowed()	\
-	((XLogArchivingActive() && pmState == PM_RUN) ||	\
-	 (XLogArchivingAlways() &&	\
-	  (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY)))
+	(((XLogArchivingActive() && pmState == PM_RUN) ||			\
+	  (XLogArchivingAlways() &&									  \
+	   (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY))) && \
+	 PgArchCanRestart())
 
 #ifdef EXEC_BACKEND
 
@@ -548,6 +549,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1794,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3009,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3144,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for
+		 * it to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3407,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3613,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3805,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and
+		 * syslogger processes are disregarded since they are not connected to
+		 * shared memory; we also disregard dead_end children here. Walsenders
+		 * and archiver are also disregarded, they will be terminated later
+		 * after writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..1e47a143e1 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,10 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern bool PgArchCanRestart(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_17_24_43_2021_866)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v55 3/3] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 240 ++++++++++-------------
 src/backend/postmaster/postmaster.c      |  81 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  14 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 164 insertions(+), 212 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..07ba989a37 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,101 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	int			pgprocno;		/* pgprocno of archiver process */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
-
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
 {
-	time_t		curtime;
-	pid_t		pgArchPid;
+	Size		size = 0;
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	size = add_size(size, sizeof(PgArchData));
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
+	return size;
+}
 
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
 
-			PgArchiverMain(0, NULL);
-			break;
-#endif
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
 
-		default:
-			return (int) pgArchPid;
+	if (!found)
+	{
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		PgArch->pgprocno = INVALID_PGPROCNO;
 	}
-
-	/* shouldn't get here */
-	return 0;
 }
 
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
 /*
- * pgarch_forkexec() -
+ *  PgArchIsSuppressed
  *
- * Format up the arglist for, then fork and exec, archive process
+ * Return true if archiver relaunch is suppressed.
+ *
+ * This is a safety valve to protect against continuous respawn attempts if the
+ * archiver is dying immediately at launch. Note that since we will retry to
+ * launch the archiver from the postmaster main loop, we will get another
+ * chance later.
  */
-static pid_t
-pgarch_forkexec(void)
+bool
+PgArchCanRestart(void)
 {
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
+	static time_t last_pgarch_start_time = 0;
+	time_t		curtime = time(NULL);
 
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
+	/*
+	 * allow to launch also for the first time and when something's wrong in
+	 * the time values.
+	 */
+	if (last_pgarch_start_time == 0 ||
+		curtime < last_pgarch_start_time ||
+		(curtime - last_pgarch_start_time) >= PGARCH_RESTART_INTERVAL)
+	{
+		last_pgarch_start_time = curtime;
 
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
+		return true;
+	}
 
-	return postmaster_forkexec(ac, av);
+	return false;
 }
-#endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +177,51 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* We shouldn't be launched unnecessarily. */
+	Assert(XLogArchivingActive());
+
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our pgproc index so that backends can use our latch to wake
+	 * us up while we're sleeping.
+	 */
+	PgArch->pgprocno = MyProc->pgprocno;
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	int			arch_pgprocno = PgArch->pgprocno;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	/*
+	 * We don't acquire ProcArrayLock here.  It's actually fine because
+	 * procLatch isn't ever freed, so we just can potentially set the wrong
+	 * process' (or no process') latch.  Even in that case the archiver will
+	 * be relaunched shortly and will start archiving.
+	 */
+	if (arch_pgprocno != INVALID_PGPROCNO)
+		SetLatch(&ProcGlobal->allProcs[arch_pgprocno].procLatch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +246,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +284,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +306,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +692,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	PgArch->pgprocno = INVALID_PGPROCNO;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..e8af05c04e 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -443,9 +443,10 @@ static void InitPostmasterDeathWatchHandle(void);
  * even during recovery.
  */
 #define PgArchStartupAllowed()	\
-	((XLogArchivingActive() && pmState == PM_RUN) ||	\
-	 (XLogArchivingAlways() &&	\
-	  (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY)))
+	(((XLogArchivingActive() && pmState == PM_RUN) ||			\
+	  (XLogArchivingAlways() &&									  \
+	   (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY))) && \
+	 PgArchCanRestart())
 
 #ifdef EXEC_BACKEND
 
@@ -548,6 +549,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1794,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3009,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3144,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for
+		 * it to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3407,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3613,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3805,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and
+		 * syslogger processes are disregarded since they are not connected to
+		 * shared memory; we also disregard dead_end children here. Walsenders
+		 * and archiver are also disregarded, they will be terminated later
+		 * after writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..1e47a143e1 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,10 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern bool PgArchCanRestart(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_17_24_43_2021_866)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v53 3/7] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 227 ++++++++---------------
 src/backend/postmaster/postmaster.c      |  74 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  13 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 137 insertions(+), 218 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..818c9a1f3f 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,70 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	Latch	   *latch;			/* latch to wake the archiver up */
+	slock_t		mutex;			/* locks this struct */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size		size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
+	return size;
+}
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
+	if (!found)
 	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		SpinLockInit(&PgArch->mutex);
+		PgArch->latch = NULL;
 	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
 }
-#endif							/* EXEC_BACKEND */
-
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +146,49 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = MyLatch;
+	SpinLockRelease(&PgArch->mutex);
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	Latch	   *latch;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
+	/* fetching the latch pointer might not be atomic, so use spinlock */
+	SpinLockAcquire(&PgArch->mutex);
+	latch = PgArch->latch;
+	SpinLockRelease(&PgArch->mutex);
 
-	errno = save_errno;
+	if (latch)
+		SetLatch(latch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +213,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +251,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +273,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +659,17 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = NULL;
+	SpinLockRelease(&PgArch->mutex);
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..460e629145 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3143,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3804,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and syslogger
+		 * processes are disregarded since they are not connected to shared
+		 * memory; we also disregard dead_end children here. Walsenders and
+		 * archiver are also disregarded, they will be terminated later after
+		 * writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3911,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5037,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5134,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5188,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5429,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..d053bf1564 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,9 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_09_23_13_2021_947)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v53 3/7] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 227 ++++++++---------------
 src/backend/postmaster/postmaster.c      |  74 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  13 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 137 insertions(+), 218 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..818c9a1f3f 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,70 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	Latch	   *latch;			/* latch to wake the archiver up */
+	slock_t		mutex;			/* locks this struct */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size		size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
+	return size;
+}
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
+	if (!found)
 	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		SpinLockInit(&PgArch->mutex);
+		PgArch->latch = NULL;
 	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
 }
-#endif							/* EXEC_BACKEND */
-
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +146,49 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = MyLatch;
+	SpinLockRelease(&PgArch->mutex);
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	Latch	   *latch;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
+	/* fetching the latch pointer might not be atomic, so use spinlock */
+	SpinLockAcquire(&PgArch->mutex);
+	latch = PgArch->latch;
+	SpinLockRelease(&PgArch->mutex);
 
-	errno = save_errno;
+	if (latch)
+		SetLatch(latch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +213,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +251,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +273,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +659,17 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = NULL;
+	SpinLockRelease(&PgArch->mutex);
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..460e629145 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3143,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3804,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and syslogger
+		 * processes are disregarded since they are not connected to shared
+		 * memory; we also disregard dead_end children here. Walsenders and
+		 * archiver are also disregarded, they will be terminated later after
+		 * writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3911,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5037,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5134,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5188,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5429,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..d053bf1564 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,9 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_09_23_13_2021_947)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v54 3/7] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 241 +++++++++--------------
 src/backend/postmaster/postmaster.c      |  81 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  14 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 160 insertions(+), 217 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..8e572afea3 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,6 +71,12 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	int		pgprocno;				/* pgprocno of archiver process */
+} PgArchData;
+
 
 /* ----------
  * Local data
@@ -80,146 +84,79 @@
  */
 static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size		size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
+
+	return size;
+}
+
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
+
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
+
+	if (!found)
+	{
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		PgArch->pgprocno = INVALID_PGPROCNO;
+	}
+}
 
 /*
- * pgarch_start
+ *  PgArchIsSuppressed
  *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
+ * Return true if archiver relaunch is suppressed.
  *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
+ * This is a safety valve to protect against continuous respawn attempts if the
+ * archiver is dying immediately at launch. Note that since we will retry to
+ * launch the archiver from the postmaster main loop, we will get another
+ * chance later.
  */
-int
-pgarch_start(void)
+bool
+PgArchIsSuppressed(void)
 {
-	time_t		curtime;
-	pid_t		pgArchPid;
+	time_t	curtime = time(NULL);
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+	if ((curtime - last_pgarch_start_time) < PGARCH_RESTART_INTERVAL)
+		return true;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
 	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
+	return false;
 }
-#endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +168,51 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* We shouldn't be launched unnecessarily. */
+	Assert(XLogArchivingActive());
+
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	PgArch->pgprocno = MyProc->pgprocno;
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	int	arch_pgprocno = PgArch->pgprocno;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	/*
+	 * We don't acquire ProcArrayLock here.  It's actually fine because
+	 * procLatch isn't ever freed, so we just can potentially set the wrong
+	 * process' (or no process') latch.  Even in that case the archiver will be
+	 * relaunched shortly and will start archiving.
+	 */
+	if (arch_pgprocno != INVALID_PGPROCNO)
+		SetLatch(&ProcGlobal->allProcs[arch_pgprocno].procLatch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +237,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +275,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +297,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +683,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	PgArch->pgprocno = INVALID_PGPROCNO;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..4f8e364284 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -443,9 +443,10 @@ static void InitPostmasterDeathWatchHandle(void);
  * even during recovery.
  */
 #define PgArchStartupAllowed()	\
-	((XLogArchivingActive() && pmState == PM_RUN) ||	\
-	 (XLogArchivingAlways() &&	\
-	  (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY)))
+	(((XLogArchivingActive() && pmState == PM_RUN) ||	\
+	  (XLogArchivingAlways() &&									\
+	   (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY))) && \
+	 !PgArchIsSuppressed())
 
 #ifdef EXEC_BACKEND
 
@@ -548,6 +549,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1794,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3009,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3144,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3407,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3613,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3805,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and syslogger
+		 * processes are disregarded since they are not connected to shared
+		 * memory; we also disregard dead_end children here. Walsenders and
+		 * archiver are also disregarded, they will be terminated later after
+		 * writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..640692d33e 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,10 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern bool PgArchIsSuppressed(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_13_49_06_2021_682)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v55 3/3] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 240 ++++++++++-------------
 src/backend/postmaster/postmaster.c      |  81 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  14 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 164 insertions(+), 212 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..07ba989a37 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,101 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	int			pgprocno;		/* pgprocno of archiver process */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
-
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
 {
-	time_t		curtime;
-	pid_t		pgArchPid;
+	Size		size = 0;
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	size = add_size(size, sizeof(PgArchData));
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
+	return size;
+}
 
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
 
-			PgArchiverMain(0, NULL);
-			break;
-#endif
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
 
-		default:
-			return (int) pgArchPid;
+	if (!found)
+	{
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		PgArch->pgprocno = INVALID_PGPROCNO;
 	}
-
-	/* shouldn't get here */
-	return 0;
 }
 
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
 /*
- * pgarch_forkexec() -
+ *  PgArchIsSuppressed
  *
- * Format up the arglist for, then fork and exec, archive process
+ * Return true if archiver relaunch is suppressed.
+ *
+ * This is a safety valve to protect against continuous respawn attempts if the
+ * archiver is dying immediately at launch. Note that since we will retry to
+ * launch the archiver from the postmaster main loop, we will get another
+ * chance later.
  */
-static pid_t
-pgarch_forkexec(void)
+bool
+PgArchCanRestart(void)
 {
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
+	static time_t last_pgarch_start_time = 0;
+	time_t		curtime = time(NULL);
 
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
+	/*
+	 * allow to launch also for the first time and when something's wrong in
+	 * the time values.
+	 */
+	if (last_pgarch_start_time == 0 ||
+		curtime < last_pgarch_start_time ||
+		(curtime - last_pgarch_start_time) >= PGARCH_RESTART_INTERVAL)
+	{
+		last_pgarch_start_time = curtime;
 
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
+		return true;
+	}
 
-	return postmaster_forkexec(ac, av);
+	return false;
 }
-#endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +177,51 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* We shouldn't be launched unnecessarily. */
+	Assert(XLogArchivingActive());
+
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our pgproc index so that backends can use our latch to wake
+	 * us up while we're sleeping.
+	 */
+	PgArch->pgprocno = MyProc->pgprocno;
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	int			arch_pgprocno = PgArch->pgprocno;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	/*
+	 * We don't acquire ProcArrayLock here.  It's actually fine because
+	 * procLatch isn't ever freed, so we just can potentially set the wrong
+	 * process' (or no process') latch.  Even in that case the archiver will
+	 * be relaunched shortly and will start archiving.
+	 */
+	if (arch_pgprocno != INVALID_PGPROCNO)
+		SetLatch(&ProcGlobal->allProcs[arch_pgprocno].procLatch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +246,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +284,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +306,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +692,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	PgArch->pgprocno = INVALID_PGPROCNO;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..e8af05c04e 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -443,9 +443,10 @@ static void InitPostmasterDeathWatchHandle(void);
  * even during recovery.
  */
 #define PgArchStartupAllowed()	\
-	((XLogArchivingActive() && pmState == PM_RUN) ||	\
-	 (XLogArchivingAlways() &&	\
-	  (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY)))
+	(((XLogArchivingActive() && pmState == PM_RUN) ||			\
+	  (XLogArchivingAlways() &&									  \
+	   (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY))) && \
+	 PgArchCanRestart())
 
 #ifdef EXEC_BACKEND
 
@@ -548,6 +549,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1794,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3009,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3144,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for
+		 * it to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3407,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3613,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3805,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and
+		 * syslogger processes are disregarded since they are not connected to
+		 * shared memory; we also disregard dead_end children here. Walsenders
+		 * and archiver are also disregarded, they will be terminated later
+		 * after writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..1e47a143e1 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,10 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern bool PgArchCanRestart(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_17_24_43_2021_866)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v53 3/7] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 227 ++++++++---------------
 src/backend/postmaster/postmaster.c      |  74 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  13 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 137 insertions(+), 218 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..818c9a1f3f 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,70 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	Latch	   *latch;			/* latch to wake the archiver up */
+	slock_t		mutex;			/* locks this struct */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size		size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
+	return size;
+}
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
+	if (!found)
 	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		SpinLockInit(&PgArch->mutex);
+		PgArch->latch = NULL;
 	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
 }
-#endif							/* EXEC_BACKEND */
-
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +146,49 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = MyLatch;
+	SpinLockRelease(&PgArch->mutex);
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	Latch	   *latch;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
+	/* fetching the latch pointer might not be atomic, so use spinlock */
+	SpinLockAcquire(&PgArch->mutex);
+	latch = PgArch->latch;
+	SpinLockRelease(&PgArch->mutex);
 
-	errno = save_errno;
+	if (latch)
+		SetLatch(latch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +213,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +251,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +273,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +659,17 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = NULL;
+	SpinLockRelease(&PgArch->mutex);
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..460e629145 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3143,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3804,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and syslogger
+		 * processes are disregarded since they are not connected to shared
+		 * memory; we also disregard dead_end children here. Walsenders and
+		 * archiver are also disregarded, they will be terminated later after
+		 * writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3911,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5037,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5134,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5188,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5429,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..d053bf1564 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,9 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_09_23_13_2021_947)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v54 3/7] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 241 +++++++++--------------
 src/backend/postmaster/postmaster.c      |  81 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  14 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 160 insertions(+), 217 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..8e572afea3 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,6 +71,12 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	int		pgprocno;				/* pgprocno of archiver process */
+} PgArchData;
+
 
 /* ----------
  * Local data
@@ -80,146 +84,79 @@
  */
 static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size		size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
+
+	return size;
+}
+
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
+
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
+
+	if (!found)
+	{
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		PgArch->pgprocno = INVALID_PGPROCNO;
+	}
+}
 
 /*
- * pgarch_start
+ *  PgArchIsSuppressed
  *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
+ * Return true if archiver relaunch is suppressed.
  *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
+ * This is a safety valve to protect against continuous respawn attempts if the
+ * archiver is dying immediately at launch. Note that since we will retry to
+ * launch the archiver from the postmaster main loop, we will get another
+ * chance later.
  */
-int
-pgarch_start(void)
+bool
+PgArchIsSuppressed(void)
 {
-	time_t		curtime;
-	pid_t		pgArchPid;
+	time_t	curtime = time(NULL);
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+	if ((curtime - last_pgarch_start_time) < PGARCH_RESTART_INTERVAL)
+		return true;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
 	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
+	return false;
 }
-#endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +168,51 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* We shouldn't be launched unnecessarily. */
+	Assert(XLogArchivingActive());
+
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	PgArch->pgprocno = MyProc->pgprocno;
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	int	arch_pgprocno = PgArch->pgprocno;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	/*
+	 * We don't acquire ProcArrayLock here.  It's actually fine because
+	 * procLatch isn't ever freed, so we just can potentially set the wrong
+	 * process' (or no process') latch.  Even in that case the archiver will be
+	 * relaunched shortly and will start archiving.
+	 */
+	if (arch_pgprocno != INVALID_PGPROCNO)
+		SetLatch(&ProcGlobal->allProcs[arch_pgprocno].procLatch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +237,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +275,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +297,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +683,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	PgArch->pgprocno = INVALID_PGPROCNO;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..4f8e364284 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -443,9 +443,10 @@ static void InitPostmasterDeathWatchHandle(void);
  * even during recovery.
  */
 #define PgArchStartupAllowed()	\
-	((XLogArchivingActive() && pmState == PM_RUN) ||	\
-	 (XLogArchivingAlways() &&	\
-	  (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY)))
+	(((XLogArchivingActive() && pmState == PM_RUN) ||	\
+	  (XLogArchivingAlways() &&									\
+	   (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY))) && \
+	 !PgArchIsSuppressed())
 
 #ifdef EXEC_BACKEND
 
@@ -548,6 +549,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1794,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3009,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3144,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3407,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3613,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3805,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and syslogger
+		 * processes are disregarded since they are not connected to shared
+		 * memory; we also disregard dead_end children here. Walsenders and
+		 * archiver are also disregarded, they will be terminated later after
+		 * writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..640692d33e 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,10 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern bool PgArchIsSuppressed(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_13_49_06_2021_682)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v55 3/3] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 240 ++++++++++-------------
 src/backend/postmaster/postmaster.c      |  81 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  14 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 164 insertions(+), 212 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..07ba989a37 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,101 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	int			pgprocno;		/* pgprocno of archiver process */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
-
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
 {
-	time_t		curtime;
-	pid_t		pgArchPid;
+	Size		size = 0;
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	size = add_size(size, sizeof(PgArchData));
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
+	return size;
+}
 
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
 
-			PgArchiverMain(0, NULL);
-			break;
-#endif
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
 
-		default:
-			return (int) pgArchPid;
+	if (!found)
+	{
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		PgArch->pgprocno = INVALID_PGPROCNO;
 	}
-
-	/* shouldn't get here */
-	return 0;
 }
 
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
 /*
- * pgarch_forkexec() -
+ *  PgArchIsSuppressed
  *
- * Format up the arglist for, then fork and exec, archive process
+ * Return true if archiver relaunch is suppressed.
+ *
+ * This is a safety valve to protect against continuous respawn attempts if the
+ * archiver is dying immediately at launch. Note that since we will retry to
+ * launch the archiver from the postmaster main loop, we will get another
+ * chance later.
  */
-static pid_t
-pgarch_forkexec(void)
+bool
+PgArchCanRestart(void)
 {
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
+	static time_t last_pgarch_start_time = 0;
+	time_t		curtime = time(NULL);
 
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
+	/*
+	 * allow to launch also for the first time and when something's wrong in
+	 * the time values.
+	 */
+	if (last_pgarch_start_time == 0 ||
+		curtime < last_pgarch_start_time ||
+		(curtime - last_pgarch_start_time) >= PGARCH_RESTART_INTERVAL)
+	{
+		last_pgarch_start_time = curtime;
 
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
+		return true;
+	}
 
-	return postmaster_forkexec(ac, av);
+	return false;
 }
-#endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +177,51 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* We shouldn't be launched unnecessarily. */
+	Assert(XLogArchivingActive());
+
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our pgproc index so that backends can use our latch to wake
+	 * us up while we're sleeping.
+	 */
+	PgArch->pgprocno = MyProc->pgprocno;
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	int			arch_pgprocno = PgArch->pgprocno;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	/*
+	 * We don't acquire ProcArrayLock here.  It's actually fine because
+	 * procLatch isn't ever freed, so we just can potentially set the wrong
+	 * process' (or no process') latch.  Even in that case the archiver will
+	 * be relaunched shortly and will start archiving.
+	 */
+	if (arch_pgprocno != INVALID_PGPROCNO)
+		SetLatch(&ProcGlobal->allProcs[arch_pgprocno].procLatch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +246,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +284,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +306,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +692,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	PgArch->pgprocno = INVALID_PGPROCNO;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..e8af05c04e 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -443,9 +443,10 @@ static void InitPostmasterDeathWatchHandle(void);
  * even during recovery.
  */
 #define PgArchStartupAllowed()	\
-	((XLogArchivingActive() && pmState == PM_RUN) ||	\
-	 (XLogArchivingAlways() &&	\
-	  (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY)))
+	(((XLogArchivingActive() && pmState == PM_RUN) ||			\
+	  (XLogArchivingAlways() &&									  \
+	   (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY))) && \
+	 PgArchCanRestart())
 
 #ifdef EXEC_BACKEND
 
@@ -548,6 +549,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1794,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3009,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3144,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for
+		 * it to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3407,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3613,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3805,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and
+		 * syslogger processes are disregarded since they are not connected to
+		 * shared memory; we also disregard dead_end children here. Walsenders
+		 * and archiver are also disregarded, they will be terminated later
+		 * after writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..1e47a143e1 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,10 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern bool PgArchCanRestart(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_17_24_43_2021_866)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v54 3/7] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 241 +++++++++--------------
 src/backend/postmaster/postmaster.c      |  81 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  14 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 160 insertions(+), 217 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..8e572afea3 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,6 +71,12 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	int		pgprocno;				/* pgprocno of archiver process */
+} PgArchData;
+
 
 /* ----------
  * Local data
@@ -80,146 +84,79 @@
  */
 static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size		size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
+
+	return size;
+}
+
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
+
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
+
+	if (!found)
+	{
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		PgArch->pgprocno = INVALID_PGPROCNO;
+	}
+}
 
 /*
- * pgarch_start
+ *  PgArchIsSuppressed
  *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
+ * Return true if archiver relaunch is suppressed.
  *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
+ * This is a safety valve to protect against continuous respawn attempts if the
+ * archiver is dying immediately at launch. Note that since we will retry to
+ * launch the archiver from the postmaster main loop, we will get another
+ * chance later.
  */
-int
-pgarch_start(void)
+bool
+PgArchIsSuppressed(void)
 {
-	time_t		curtime;
-	pid_t		pgArchPid;
+	time_t	curtime = time(NULL);
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+	if ((curtime - last_pgarch_start_time) < PGARCH_RESTART_INTERVAL)
+		return true;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
 	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
+	return false;
 }
-#endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +168,51 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* We shouldn't be launched unnecessarily. */
+	Assert(XLogArchivingActive());
+
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	PgArch->pgprocno = MyProc->pgprocno;
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	int	arch_pgprocno = PgArch->pgprocno;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	/*
+	 * We don't acquire ProcArrayLock here.  It's actually fine because
+	 * procLatch isn't ever freed, so we just can potentially set the wrong
+	 * process' (or no process') latch.  Even in that case the archiver will be
+	 * relaunched shortly and will start archiving.
+	 */
+	if (arch_pgprocno != INVALID_PGPROCNO)
+		SetLatch(&ProcGlobal->allProcs[arch_pgprocno].procLatch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +237,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +275,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +297,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +683,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	PgArch->pgprocno = INVALID_PGPROCNO;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..4f8e364284 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -443,9 +443,10 @@ static void InitPostmasterDeathWatchHandle(void);
  * even during recovery.
  */
 #define PgArchStartupAllowed()	\
-	((XLogArchivingActive() && pmState == PM_RUN) ||	\
-	 (XLogArchivingAlways() &&	\
-	  (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY)))
+	(((XLogArchivingActive() && pmState == PM_RUN) ||	\
+	  (XLogArchivingAlways() &&									\
+	   (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY))) && \
+	 !PgArchIsSuppressed())
 
 #ifdef EXEC_BACKEND
 
@@ -548,6 +549,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1794,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3009,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3144,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3407,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3613,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3805,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and syslogger
+		 * processes are disregarded since they are not connected to shared
+		 * memory; we also disregard dead_end children here. Walsenders and
+		 * archiver are also disregarded, they will be terminated later after
+		 * writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..640692d33e 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,10 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern bool PgArchIsSuppressed(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_13_49_06_2021_682)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v55 3/3] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 240 ++++++++++-------------
 src/backend/postmaster/postmaster.c      |  81 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  14 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 164 insertions(+), 212 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..07ba989a37 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,101 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	int			pgprocno;		/* pgprocno of archiver process */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
-
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
 {
-	time_t		curtime;
-	pid_t		pgArchPid;
+	Size		size = 0;
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	size = add_size(size, sizeof(PgArchData));
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
+	return size;
+}
 
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
 
-			PgArchiverMain(0, NULL);
-			break;
-#endif
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
 
-		default:
-			return (int) pgArchPid;
+	if (!found)
+	{
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		PgArch->pgprocno = INVALID_PGPROCNO;
 	}
-
-	/* shouldn't get here */
-	return 0;
 }
 
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
 /*
- * pgarch_forkexec() -
+ *  PgArchIsSuppressed
  *
- * Format up the arglist for, then fork and exec, archive process
+ * Return true if archiver relaunch is suppressed.
+ *
+ * This is a safety valve to protect against continuous respawn attempts if the
+ * archiver is dying immediately at launch. Note that since we will retry to
+ * launch the archiver from the postmaster main loop, we will get another
+ * chance later.
  */
-static pid_t
-pgarch_forkexec(void)
+bool
+PgArchCanRestart(void)
 {
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
+	static time_t last_pgarch_start_time = 0;
+	time_t		curtime = time(NULL);
 
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
+	/*
+	 * allow to launch also for the first time and when something's wrong in
+	 * the time values.
+	 */
+	if (last_pgarch_start_time == 0 ||
+		curtime < last_pgarch_start_time ||
+		(curtime - last_pgarch_start_time) >= PGARCH_RESTART_INTERVAL)
+	{
+		last_pgarch_start_time = curtime;
 
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
+		return true;
+	}
 
-	return postmaster_forkexec(ac, av);
+	return false;
 }
-#endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +177,51 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* We shouldn't be launched unnecessarily. */
+	Assert(XLogArchivingActive());
+
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our pgproc index so that backends can use our latch to wake
+	 * us up while we're sleeping.
+	 */
+	PgArch->pgprocno = MyProc->pgprocno;
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	int			arch_pgprocno = PgArch->pgprocno;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	/*
+	 * We don't acquire ProcArrayLock here.  It's actually fine because
+	 * procLatch isn't ever freed, so we just can potentially set the wrong
+	 * process' (or no process') latch.  Even in that case the archiver will
+	 * be relaunched shortly and will start archiving.
+	 */
+	if (arch_pgprocno != INVALID_PGPROCNO)
+		SetLatch(&ProcGlobal->allProcs[arch_pgprocno].procLatch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +246,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +284,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +306,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +692,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	PgArch->pgprocno = INVALID_PGPROCNO;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..e8af05c04e 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -443,9 +443,10 @@ static void InitPostmasterDeathWatchHandle(void);
  * even during recovery.
  */
 #define PgArchStartupAllowed()	\
-	((XLogArchivingActive() && pmState == PM_RUN) ||	\
-	 (XLogArchivingAlways() &&	\
-	  (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY)))
+	(((XLogArchivingActive() && pmState == PM_RUN) ||			\
+	  (XLogArchivingAlways() &&									  \
+	   (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY))) && \
+	 PgArchCanRestart())
 
 #ifdef EXEC_BACKEND
 
@@ -548,6 +549,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1794,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3009,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3144,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for
+		 * it to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3407,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3613,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3805,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and
+		 * syslogger processes are disregarded since they are not connected to
+		 * shared memory; we also disregard dead_end children here. Walsenders
+		 * and archiver are also disregarded, they will be terminated later
+		 * after writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..1e47a143e1 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,10 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern bool PgArchCanRestart(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_17_24_43_2021_866)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v53 3/7] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 227 ++++++++---------------
 src/backend/postmaster/postmaster.c      |  74 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  13 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 137 insertions(+), 218 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..818c9a1f3f 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,70 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	Latch	   *latch;			/* latch to wake the archiver up */
+	slock_t		mutex;			/* locks this struct */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size		size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
+	return size;
+}
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
+	if (!found)
 	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		SpinLockInit(&PgArch->mutex);
+		PgArch->latch = NULL;
 	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
 }
-#endif							/* EXEC_BACKEND */
-
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +146,49 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = MyLatch;
+	SpinLockRelease(&PgArch->mutex);
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	Latch	   *latch;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
+	/* fetching the latch pointer might not be atomic, so use spinlock */
+	SpinLockAcquire(&PgArch->mutex);
+	latch = PgArch->latch;
+	SpinLockRelease(&PgArch->mutex);
 
-	errno = save_errno;
+	if (latch)
+		SetLatch(latch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +213,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +251,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +273,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +659,17 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = NULL;
+	SpinLockRelease(&PgArch->mutex);
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..460e629145 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3143,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3804,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and syslogger
+		 * processes are disregarded since they are not connected to shared
+		 * memory; we also disregard dead_end children here. Walsenders and
+		 * archiver are also disregarded, they will be terminated later after
+		 * writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3911,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5037,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5134,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5188,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5429,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..d053bf1564 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,9 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_09_23_13_2021_947)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v54 3/7] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 241 +++++++++--------------
 src/backend/postmaster/postmaster.c      |  81 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  14 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 160 insertions(+), 217 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..8e572afea3 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,6 +71,12 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	int		pgprocno;				/* pgprocno of archiver process */
+} PgArchData;
+
 
 /* ----------
  * Local data
@@ -80,146 +84,79 @@
  */
 static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size		size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
+
+	return size;
+}
+
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
+
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
+
+	if (!found)
+	{
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		PgArch->pgprocno = INVALID_PGPROCNO;
+	}
+}
 
 /*
- * pgarch_start
+ *  PgArchIsSuppressed
  *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
+ * Return true if archiver relaunch is suppressed.
  *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
+ * This is a safety valve to protect against continuous respawn attempts if the
+ * archiver is dying immediately at launch. Note that since we will retry to
+ * launch the archiver from the postmaster main loop, we will get another
+ * chance later.
  */
-int
-pgarch_start(void)
+bool
+PgArchIsSuppressed(void)
 {
-	time_t		curtime;
-	pid_t		pgArchPid;
+	time_t	curtime = time(NULL);
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+	if ((curtime - last_pgarch_start_time) < PGARCH_RESTART_INTERVAL)
+		return true;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
 	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
+	return false;
 }
-#endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +168,51 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* We shouldn't be launched unnecessarily. */
+	Assert(XLogArchivingActive());
+
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	PgArch->pgprocno = MyProc->pgprocno;
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	int	arch_pgprocno = PgArch->pgprocno;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	/*
+	 * We don't acquire ProcArrayLock here.  It's actually fine because
+	 * procLatch isn't ever freed, so we just can potentially set the wrong
+	 * process' (or no process') latch.  Even in that case the archiver will be
+	 * relaunched shortly and will start archiving.
+	 */
+	if (arch_pgprocno != INVALID_PGPROCNO)
+		SetLatch(&ProcGlobal->allProcs[arch_pgprocno].procLatch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +237,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +275,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +297,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +683,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	PgArch->pgprocno = INVALID_PGPROCNO;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..4f8e364284 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -443,9 +443,10 @@ static void InitPostmasterDeathWatchHandle(void);
  * even during recovery.
  */
 #define PgArchStartupAllowed()	\
-	((XLogArchivingActive() && pmState == PM_RUN) ||	\
-	 (XLogArchivingAlways() &&	\
-	  (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY)))
+	(((XLogArchivingActive() && pmState == PM_RUN) ||	\
+	  (XLogArchivingAlways() &&									\
+	   (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY))) && \
+	 !PgArchIsSuppressed())
 
 #ifdef EXEC_BACKEND
 
@@ -548,6 +549,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1794,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3009,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3144,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3407,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3613,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3805,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and syslogger
+		 * processes are disregarded since they are not connected to shared
+		 * memory; we also disregard dead_end children here. Walsenders and
+		 * archiver are also disregarded, they will be terminated later after
+		 * writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..640692d33e 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,10 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern bool PgArchIsSuppressed(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_13_49_06_2021_682)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v53 3/7] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 227 ++++++++---------------
 src/backend/postmaster/postmaster.c      |  74 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  13 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 137 insertions(+), 218 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..818c9a1f3f 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,70 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	Latch	   *latch;			/* latch to wake the archiver up */
+	slock_t		mutex;			/* locks this struct */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size		size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
+	return size;
+}
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
+	if (!found)
 	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		SpinLockInit(&PgArch->mutex);
+		PgArch->latch = NULL;
 	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
 }
-#endif							/* EXEC_BACKEND */
-
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +146,49 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = MyLatch;
+	SpinLockRelease(&PgArch->mutex);
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	Latch	   *latch;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
+	/* fetching the latch pointer might not be atomic, so use spinlock */
+	SpinLockAcquire(&PgArch->mutex);
+	latch = PgArch->latch;
+	SpinLockRelease(&PgArch->mutex);
 
-	errno = save_errno;
+	if (latch)
+		SetLatch(latch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +213,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +251,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +273,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +659,17 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = NULL;
+	SpinLockRelease(&PgArch->mutex);
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..460e629145 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3143,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3804,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and syslogger
+		 * processes are disregarded since they are not connected to shared
+		 * memory; we also disregard dead_end children here. Walsenders and
+		 * archiver are also disregarded, they will be terminated later after
+		 * writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3911,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5037,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5134,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5188,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5429,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..d053bf1564 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,9 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_09_23_13_2021_947)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v54 3/7] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 241 +++++++++--------------
 src/backend/postmaster/postmaster.c      |  81 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  14 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 160 insertions(+), 217 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..8e572afea3 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,6 +71,12 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	int		pgprocno;				/* pgprocno of archiver process */
+} PgArchData;
+
 
 /* ----------
  * Local data
@@ -80,146 +84,79 @@
  */
 static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size		size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
+
+	return size;
+}
+
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
+
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
+
+	if (!found)
+	{
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		PgArch->pgprocno = INVALID_PGPROCNO;
+	}
+}
 
 /*
- * pgarch_start
+ *  PgArchIsSuppressed
  *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
+ * Return true if archiver relaunch is suppressed.
  *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
+ * This is a safety valve to protect against continuous respawn attempts if the
+ * archiver is dying immediately at launch. Note that since we will retry to
+ * launch the archiver from the postmaster main loop, we will get another
+ * chance later.
  */
-int
-pgarch_start(void)
+bool
+PgArchIsSuppressed(void)
 {
-	time_t		curtime;
-	pid_t		pgArchPid;
+	time_t	curtime = time(NULL);
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+	if ((curtime - last_pgarch_start_time) < PGARCH_RESTART_INTERVAL)
+		return true;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
 	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
+	return false;
 }
-#endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +168,51 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* We shouldn't be launched unnecessarily. */
+	Assert(XLogArchivingActive());
+
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	PgArch->pgprocno = MyProc->pgprocno;
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	int	arch_pgprocno = PgArch->pgprocno;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	/*
+	 * We don't acquire ProcArrayLock here.  It's actually fine because
+	 * procLatch isn't ever freed, so we just can potentially set the wrong
+	 * process' (or no process') latch.  Even in that case the archiver will be
+	 * relaunched shortly and will start archiving.
+	 */
+	if (arch_pgprocno != INVALID_PGPROCNO)
+		SetLatch(&ProcGlobal->allProcs[arch_pgprocno].procLatch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +237,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +275,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +297,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +683,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	PgArch->pgprocno = INVALID_PGPROCNO;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..4f8e364284 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -443,9 +443,10 @@ static void InitPostmasterDeathWatchHandle(void);
  * even during recovery.
  */
 #define PgArchStartupAllowed()	\
-	((XLogArchivingActive() && pmState == PM_RUN) ||	\
-	 (XLogArchivingAlways() &&	\
-	  (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY)))
+	(((XLogArchivingActive() && pmState == PM_RUN) ||	\
+	  (XLogArchivingAlways() &&									\
+	   (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY))) && \
+	 !PgArchIsSuppressed())
 
 #ifdef EXEC_BACKEND
 
@@ -548,6 +549,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1794,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3009,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3144,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3407,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3613,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3805,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and syslogger
+		 * processes are disregarded since they are not connected to shared
+		 * memory; we also disregard dead_end children here. Walsenders and
+		 * archiver are also disregarded, they will be terminated later after
+		 * writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..640692d33e 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,10 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern bool PgArchIsSuppressed(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_13_49_06_2021_682)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v55 3/3] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 240 ++++++++++-------------
 src/backend/postmaster/postmaster.c      |  81 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  14 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 164 insertions(+), 212 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..07ba989a37 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,101 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	int			pgprocno;		/* pgprocno of archiver process */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
-
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
 {
-	time_t		curtime;
-	pid_t		pgArchPid;
+	Size		size = 0;
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	size = add_size(size, sizeof(PgArchData));
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
+	return size;
+}
 
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
 
-			PgArchiverMain(0, NULL);
-			break;
-#endif
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
 
-		default:
-			return (int) pgArchPid;
+	if (!found)
+	{
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		PgArch->pgprocno = INVALID_PGPROCNO;
 	}
-
-	/* shouldn't get here */
-	return 0;
 }
 
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
 /*
- * pgarch_forkexec() -
+ *  PgArchIsSuppressed
  *
- * Format up the arglist for, then fork and exec, archive process
+ * Return true if archiver relaunch is suppressed.
+ *
+ * This is a safety valve to protect against continuous respawn attempts if the
+ * archiver is dying immediately at launch. Note that since we will retry to
+ * launch the archiver from the postmaster main loop, we will get another
+ * chance later.
  */
-static pid_t
-pgarch_forkexec(void)
+bool
+PgArchCanRestart(void)
 {
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
+	static time_t last_pgarch_start_time = 0;
+	time_t		curtime = time(NULL);
 
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
+	/*
+	 * allow to launch also for the first time and when something's wrong in
+	 * the time values.
+	 */
+	if (last_pgarch_start_time == 0 ||
+		curtime < last_pgarch_start_time ||
+		(curtime - last_pgarch_start_time) >= PGARCH_RESTART_INTERVAL)
+	{
+		last_pgarch_start_time = curtime;
 
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
+		return true;
+	}
 
-	return postmaster_forkexec(ac, av);
+	return false;
 }
-#endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +177,51 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* We shouldn't be launched unnecessarily. */
+	Assert(XLogArchivingActive());
+
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our pgproc index so that backends can use our latch to wake
+	 * us up while we're sleeping.
+	 */
+	PgArch->pgprocno = MyProc->pgprocno;
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	int			arch_pgprocno = PgArch->pgprocno;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	/*
+	 * We don't acquire ProcArrayLock here.  It's actually fine because
+	 * procLatch isn't ever freed, so we just can potentially set the wrong
+	 * process' (or no process') latch.  Even in that case the archiver will
+	 * be relaunched shortly and will start archiving.
+	 */
+	if (arch_pgprocno != INVALID_PGPROCNO)
+		SetLatch(&ProcGlobal->allProcs[arch_pgprocno].procLatch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +246,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +284,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +306,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +692,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	PgArch->pgprocno = INVALID_PGPROCNO;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..e8af05c04e 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -443,9 +443,10 @@ static void InitPostmasterDeathWatchHandle(void);
  * even during recovery.
  */
 #define PgArchStartupAllowed()	\
-	((XLogArchivingActive() && pmState == PM_RUN) ||	\
-	 (XLogArchivingAlways() &&	\
-	  (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY)))
+	(((XLogArchivingActive() && pmState == PM_RUN) ||			\
+	  (XLogArchivingAlways() &&									  \
+	   (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY))) && \
+	 PgArchCanRestart())
 
 #ifdef EXEC_BACKEND
 
@@ -548,6 +549,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1794,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3009,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3144,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for
+		 * it to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3407,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3613,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3805,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and
+		 * syslogger processes are disregarded since they are not connected to
+		 * shared memory; we also disregard dead_end children here. Walsenders
+		 * and archiver are also disregarded, they will be terminated later
+		 * after writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..1e47a143e1 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,10 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern bool PgArchCanRestart(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_17_24_43_2021_866)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v53 3/7] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 227 ++++++++---------------
 src/backend/postmaster/postmaster.c      |  74 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  13 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 137 insertions(+), 218 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..818c9a1f3f 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,70 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	Latch	   *latch;			/* latch to wake the archiver up */
+	slock_t		mutex;			/* locks this struct */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size		size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
+	return size;
+}
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
+	if (!found)
 	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		SpinLockInit(&PgArch->mutex);
+		PgArch->latch = NULL;
 	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
 }
-#endif							/* EXEC_BACKEND */
-
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +146,49 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = MyLatch;
+	SpinLockRelease(&PgArch->mutex);
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	Latch	   *latch;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
+	/* fetching the latch pointer might not be atomic, so use spinlock */
+	SpinLockAcquire(&PgArch->mutex);
+	latch = PgArch->latch;
+	SpinLockRelease(&PgArch->mutex);
 
-	errno = save_errno;
+	if (latch)
+		SetLatch(latch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +213,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +251,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +273,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +659,17 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = NULL;
+	SpinLockRelease(&PgArch->mutex);
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..460e629145 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3143,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3804,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and syslogger
+		 * processes are disregarded since they are not connected to shared
+		 * memory; we also disregard dead_end children here. Walsenders and
+		 * archiver are also disregarded, they will be terminated later after
+		 * writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3911,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5037,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5134,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5188,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5429,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..d053bf1564 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,9 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_09_23_13_2021_947)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v54 3/7] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 241 +++++++++--------------
 src/backend/postmaster/postmaster.c      |  81 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  14 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 160 insertions(+), 217 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..8e572afea3 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,6 +71,12 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	int		pgprocno;				/* pgprocno of archiver process */
+} PgArchData;
+
 
 /* ----------
  * Local data
@@ -80,146 +84,79 @@
  */
 static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size		size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
+
+	return size;
+}
+
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
+
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
+
+	if (!found)
+	{
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		PgArch->pgprocno = INVALID_PGPROCNO;
+	}
+}
 
 /*
- * pgarch_start
+ *  PgArchIsSuppressed
  *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
+ * Return true if archiver relaunch is suppressed.
  *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
+ * This is a safety valve to protect against continuous respawn attempts if the
+ * archiver is dying immediately at launch. Note that since we will retry to
+ * launch the archiver from the postmaster main loop, we will get another
+ * chance later.
  */
-int
-pgarch_start(void)
+bool
+PgArchIsSuppressed(void)
 {
-	time_t		curtime;
-	pid_t		pgArchPid;
+	time_t	curtime = time(NULL);
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+	if ((curtime - last_pgarch_start_time) < PGARCH_RESTART_INTERVAL)
+		return true;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
 	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
+	return false;
 }
-#endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +168,51 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* We shouldn't be launched unnecessarily. */
+	Assert(XLogArchivingActive());
+
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	PgArch->pgprocno = MyProc->pgprocno;
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	int	arch_pgprocno = PgArch->pgprocno;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	/*
+	 * We don't acquire ProcArrayLock here.  It's actually fine because
+	 * procLatch isn't ever freed, so we just can potentially set the wrong
+	 * process' (or no process') latch.  Even in that case the archiver will be
+	 * relaunched shortly and will start archiving.
+	 */
+	if (arch_pgprocno != INVALID_PGPROCNO)
+		SetLatch(&ProcGlobal->allProcs[arch_pgprocno].procLatch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +237,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +275,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +297,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +683,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	PgArch->pgprocno = INVALID_PGPROCNO;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..4f8e364284 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -443,9 +443,10 @@ static void InitPostmasterDeathWatchHandle(void);
  * even during recovery.
  */
 #define PgArchStartupAllowed()	\
-	((XLogArchivingActive() && pmState == PM_RUN) ||	\
-	 (XLogArchivingAlways() &&	\
-	  (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY)))
+	(((XLogArchivingActive() && pmState == PM_RUN) ||	\
+	  (XLogArchivingAlways() &&									\
+	   (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY))) && \
+	 !PgArchIsSuppressed())
 
 #ifdef EXEC_BACKEND
 
@@ -548,6 +549,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1794,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3009,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3144,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3407,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3613,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3805,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and syslogger
+		 * processes are disregarded since they are not connected to shared
+		 * memory; we also disregard dead_end children here. Walsenders and
+		 * archiver are also disregarded, they will be terminated later after
+		 * writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..640692d33e 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,10 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern bool PgArchIsSuppressed(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_13_49_06_2021_682)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v55 3/3] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 240 ++++++++++-------------
 src/backend/postmaster/postmaster.c      |  81 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  14 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 164 insertions(+), 212 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..07ba989a37 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,101 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	int			pgprocno;		/* pgprocno of archiver process */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
-
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
 {
-	time_t		curtime;
-	pid_t		pgArchPid;
+	Size		size = 0;
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	size = add_size(size, sizeof(PgArchData));
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
+	return size;
+}
 
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
 
-			PgArchiverMain(0, NULL);
-			break;
-#endif
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
 
-		default:
-			return (int) pgArchPid;
+	if (!found)
+	{
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		PgArch->pgprocno = INVALID_PGPROCNO;
 	}
-
-	/* shouldn't get here */
-	return 0;
 }
 
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
 /*
- * pgarch_forkexec() -
+ *  PgArchIsSuppressed
  *
- * Format up the arglist for, then fork and exec, archive process
+ * Return true if archiver relaunch is suppressed.
+ *
+ * This is a safety valve to protect against continuous respawn attempts if the
+ * archiver is dying immediately at launch. Note that since we will retry to
+ * launch the archiver from the postmaster main loop, we will get another
+ * chance later.
  */
-static pid_t
-pgarch_forkexec(void)
+bool
+PgArchCanRestart(void)
 {
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
+	static time_t last_pgarch_start_time = 0;
+	time_t		curtime = time(NULL);
 
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
+	/*
+	 * allow to launch also for the first time and when something's wrong in
+	 * the time values.
+	 */
+	if (last_pgarch_start_time == 0 ||
+		curtime < last_pgarch_start_time ||
+		(curtime - last_pgarch_start_time) >= PGARCH_RESTART_INTERVAL)
+	{
+		last_pgarch_start_time = curtime;
 
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
+		return true;
+	}
 
-	return postmaster_forkexec(ac, av);
+	return false;
 }
-#endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +177,51 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* We shouldn't be launched unnecessarily. */
+	Assert(XLogArchivingActive());
+
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our pgproc index so that backends can use our latch to wake
+	 * us up while we're sleeping.
+	 */
+	PgArch->pgprocno = MyProc->pgprocno;
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	int			arch_pgprocno = PgArch->pgprocno;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	/*
+	 * We don't acquire ProcArrayLock here.  It's actually fine because
+	 * procLatch isn't ever freed, so we just can potentially set the wrong
+	 * process' (or no process') latch.  Even in that case the archiver will
+	 * be relaunched shortly and will start archiving.
+	 */
+	if (arch_pgprocno != INVALID_PGPROCNO)
+		SetLatch(&ProcGlobal->allProcs[arch_pgprocno].procLatch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +246,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +284,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +306,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +692,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	PgArch->pgprocno = INVALID_PGPROCNO;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..e8af05c04e 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -443,9 +443,10 @@ static void InitPostmasterDeathWatchHandle(void);
  * even during recovery.
  */
 #define PgArchStartupAllowed()	\
-	((XLogArchivingActive() && pmState == PM_RUN) ||	\
-	 (XLogArchivingAlways() &&	\
-	  (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY)))
+	(((XLogArchivingActive() && pmState == PM_RUN) ||			\
+	  (XLogArchivingAlways() &&									  \
+	   (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY))) && \
+	 PgArchCanRestart())
 
 #ifdef EXEC_BACKEND
 
@@ -548,6 +549,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1794,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3009,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3144,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for
+		 * it to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3407,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3613,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3805,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and
+		 * syslogger processes are disregarded since they are not connected to
+		 * shared memory; we also disregard dead_end children here. Walsenders
+		 * and archiver are also disregarded, they will be terminated later
+		 * after writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..1e47a143e1 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,10 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern bool PgArchCanRestart(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_17_24_43_2021_866)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v53 3/7] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 227 ++++++++---------------
 src/backend/postmaster/postmaster.c      |  74 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  13 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 137 insertions(+), 218 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..818c9a1f3f 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,70 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	Latch	   *latch;			/* latch to wake the archiver up */
+	slock_t		mutex;			/* locks this struct */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size		size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
 
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
-{
-	time_t		curtime;
-	pid_t		pgArchPid;
+	return size;
+}
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
+	if (!found)
 	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		SpinLockInit(&PgArch->mutex);
+		PgArch->latch = NULL;
 	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
 }
-#endif							/* EXEC_BACKEND */
-
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +146,49 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = MyLatch;
+	SpinLockRelease(&PgArch->mutex);
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	Latch	   *latch;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
+	/* fetching the latch pointer might not be atomic, so use spinlock */
+	SpinLockAcquire(&PgArch->mutex);
+	latch = PgArch->latch;
+	SpinLockRelease(&PgArch->mutex);
 
-	errno = save_errno;
+	if (latch)
+		SetLatch(latch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +213,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +251,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +273,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +659,17 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	SpinLockAcquire(&PgArch->mutex);
+	PgArch->latch = NULL;
+	SpinLockRelease(&PgArch->mutex);
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..460e629145 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -548,6 +548,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1793,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3008,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3143,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3406,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3612,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3804,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and syslogger
+		 * processes are disregarded since they are not connected to shared
+		 * memory; we also disregard dead_end children here. Walsenders and
+		 * archiver are also disregarded, they will be terminated later after
+		 * writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3911,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5037,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5134,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5188,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5429,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..d053bf1564 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,9 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_09_23_13_2021_947)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v54 3/7] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 241 +++++++++--------------
 src/backend/postmaster/postmaster.c      |  81 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  14 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 160 insertions(+), 217 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..8e572afea3 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,6 +71,12 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	int		pgprocno;				/* pgprocno of archiver process */
+} PgArchData;
+
 
 /* ----------
  * Local data
@@ -80,146 +84,79 @@
  */
 static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
+{
+	Size		size = 0;
 
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
+	size = add_size(size, sizeof(PgArchData));
+
+	return size;
+}
+
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
+
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
+
+	if (!found)
+	{
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		PgArch->pgprocno = INVALID_PGPROCNO;
+	}
+}
 
 /*
- * pgarch_start
+ *  PgArchIsSuppressed
  *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
+ * Return true if archiver relaunch is suppressed.
  *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
+ * This is a safety valve to protect against continuous respawn attempts if the
+ * archiver is dying immediately at launch. Note that since we will retry to
+ * launch the archiver from the postmaster main loop, we will get another
+ * chance later.
  */
-int
-pgarch_start(void)
+bool
+PgArchIsSuppressed(void)
 {
-	time_t		curtime;
-	pid_t		pgArchPid;
+	time_t	curtime = time(NULL);
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
+	if ((curtime - last_pgarch_start_time) < PGARCH_RESTART_INTERVAL)
+		return true;
 
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
 	last_pgarch_start_time = curtime;
-
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
-
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
-
-			PgArchiverMain(0, NULL);
-			break;
-#endif
-
-		default:
-			return (int) pgArchPid;
-	}
-
-	/* shouldn't get here */
-	return 0;
-}
-
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
-/*
- * pgarch_forkexec() -
- *
- * Format up the arglist for, then fork and exec, archive process
- */
-static pid_t
-pgarch_forkexec(void)
-{
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
-
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
-
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
-
-	return postmaster_forkexec(ac, av);
+	return false;
 }
-#endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +168,51 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* We shouldn't be launched unnecessarily. */
+	Assert(XLogArchivingActive());
+
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our latch that backends can use to wake us up while we're
+	 * sleeping.
+	 */
+	PgArch->pgprocno = MyProc->pgprocno;
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	int	arch_pgprocno = PgArch->pgprocno;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	/*
+	 * We don't acquire ProcArrayLock here.  It's actually fine because
+	 * procLatch isn't ever freed, so we just can potentially set the wrong
+	 * process' (or no process') latch.  Even in that case the archiver will be
+	 * relaunched shortly and will start archiving.
+	 */
+	if (arch_pgprocno != INVALID_PGPROCNO)
+		SetLatch(&ProcGlobal->allProcs[arch_pgprocno].procLatch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +237,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +275,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +297,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +683,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	PgArch->pgprocno = INVALID_PGPROCNO;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..4f8e364284 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -443,9 +443,10 @@ static void InitPostmasterDeathWatchHandle(void);
  * even during recovery.
  */
 #define PgArchStartupAllowed()	\
-	((XLogArchivingActive() && pmState == PM_RUN) ||	\
-	 (XLogArchivingAlways() &&	\
-	  (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY)))
+	(((XLogArchivingActive() && pmState == PM_RUN) ||	\
+	  (XLogArchivingAlways() &&									\
+	   (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY))) && \
+	 !PgArchIsSuppressed())
 
 #ifdef EXEC_BACKEND
 
@@ -548,6 +549,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1794,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3009,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3144,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for it
+		 * to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3407,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3613,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3805,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and syslogger
+		 * processes are disregarded since they are not connected to shared
+		 * memory; we also disregard dead_end children here. Walsenders and
+		 * archiver are also disregarded, they will be terminated later after
+		 * writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..640692d33e 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,10 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern bool PgArchIsSuppressed(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_13_49_06_2021_682)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* [PATCH v55 3/3] Make archiver process an auxiliary process
@ 2021-03-11 09:01  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Kyotaro Horiguchi @ 2021-03-11 09:01 UTC (permalink / raw)

This makes it possible to archiver process uses ipc functions and let
us monitor archiver process status.
---
 doc/src/sgml/monitoring.sgml             |   1 +
 src/backend/access/transam/xlogarchive.c |   4 +-
 src/backend/bootstrap/bootstrap.c        |  22 ++-
 src/backend/postmaster/pgarch.c          | 240 ++++++++++-------------
 src/backend/postmaster/postmaster.c      |  81 ++++----
 src/backend/storage/ipc/ipci.c           |   2 +
 src/include/miscadmin.h                  |   2 +
 src/include/postmaster/pgarch.h          |  14 +-
 src/include/storage/pmsignal.h           |   1 -
 src/include/storage/proc.h               |   8 +-
 src/tools/pgindent/typedefs.list         |   1 +
 11 files changed, 164 insertions(+), 212 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1ba813bbb9..a96455bdb2 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -935,6 +935,7 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>logical replication worker</literal>,
        <literal>parallel worker</literal>, <literal>background writer</literal>,
        <literal>client backend</literal>, <literal>checkpointer</literal>,
+       <literal>archiver</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
        <literal>walsender</literal> and <literal>walwriter</literal>.
        In addition, background workers registered by extensions may have
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c
index 1c5a4f8b5a..26b023e754 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -25,11 +25,11 @@
 #include "common/archive.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"
+#include "postmaster/pgarch.h"
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
-#include "storage/pmsignal.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.
@@ -491,7 +491,7 @@ XLogArchiveNotify(const char *xlog)
 
 	/* Notify archiver that it's got something to do */
 	if (IsUnderPostmaster)
-		SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
+		PgArchWakeup();
 }
 
 /*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..41da0c5059 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -317,6 +317,9 @@ AuxiliaryProcessMain(int argc, char *argv[])
 		case StartupProcess:
 			MyBackendType = B_STARTUP;
 			break;
+		case ArchiverProcess:
+			MyBackendType = B_ARCHIVER;
+			break;
 		case BgWriterProcess:
 			MyBackendType = B_BG_WRITER;
 			break;
@@ -437,30 +440,29 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);		/* should never return */
 
 		case StartupProcess:
-			/* don't set signals, startup process has its own agenda */
 			StartupProcessMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
+
+		case ArchiverProcess:
+			PgArchiverMain();
+			proc_exit(1);
 
 		case BgWriterProcess:
-			/* don't set signals, bgwriter has its own agenda */
 			BackgroundWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case CheckpointerProcess:
-			/* don't set signals, checkpointer has its own agenda */
 			CheckpointerMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalWriterProcess:
-			/* don't set signals, walwriter has its own agenda */
 			InitXLOGAccess();
 			WalWriterMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		case WalReceiverProcess:
-			/* don't set signals, walreceiver has its own agenda */
 			WalReceiverMain();
-			proc_exit(1);		/* should never return */
+			proc_exit(1);
 
 		default:
 			elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index edec311f12..07ba989a37 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -38,16 +38,14 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
-#include "postmaster/fork_process.h"
 #include "postmaster/interrupt.h"
 #include "postmaster/pgarch.h"
-#include "postmaster/postmaster.h"
-#include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/latch.h"
-#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/spin.h"
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
@@ -73,153 +71,101 @@
  */
 #define NUM_ORPHAN_CLEANUP_RETRIES 3
 
+/* Shared memory area for archiver process */
+typedef struct PgArchData
+{
+	int			pgprocno;		/* pgprocno of archiver process */
+} PgArchData;
+
 
 /* ----------
  * Local data
  * ----------
  */
-static time_t last_pgarch_start_time;
 static time_t last_sigterm_time = 0;
+static PgArchData *PgArch = NULL;
 
 /*
  * Flags set by interrupt handlers for later service in the main loop.
  */
-static volatile sig_atomic_t wakened = false;
 static volatile sig_atomic_t ready_to_stop = false;
 
 /* ----------
  * Local function forward declarations
  * ----------
  */
-#ifdef EXEC_BACKEND
-static pid_t pgarch_forkexec(void);
-#endif
-
-NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
 static bool pgarch_archiveXlog(char *xlog);
 static bool pgarch_readyXlog(char *xlog);
 static void pgarch_archiveDone(char *xlog);
+static void pgarch_die(int code, Datum arg);
 
-
-/* ------------------------------------------------------------
- * Public functions called from postmaster follow
- * ------------------------------------------------------------
- */
-
-/*
- * pgarch_start
- *
- *	Called from postmaster at startup or after an existing archiver
- *	died.  Attempt to fire up a fresh archiver process.
- *
- *	Returns PID of child process, or 0 if fail.
- *
- *	Note: if fail, we will be called again from the postmaster main loop.
- */
-int
-pgarch_start(void)
+/* Report shared memory space needed by PgArchShmemInit */
+Size
+PgArchShmemSize(void)
 {
-	time_t		curtime;
-	pid_t		pgArchPid;
+	Size		size = 0;
 
-	/*
-	 * Do nothing if no archiver needed
-	 */
-	if (!XLogArchivingActive())
-		return 0;
-
-	/*
-	 * Do nothing if too soon since last archiver start.  This is a safety
-	 * valve to protect against continuous respawn attempts if the archiver is
-	 * dying immediately at launch. Note that since we will be re-called from
-	 * the postmaster main loop, we will get another chance later.
-	 */
-	curtime = time(NULL);
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return 0;
-	last_pgarch_start_time = curtime;
+	size = add_size(size, sizeof(PgArchData));
 
-#ifdef EXEC_BACKEND
-	switch ((pgArchPid = pgarch_forkexec()))
-#else
-	switch ((pgArchPid = fork_process()))
-#endif
-	{
-		case -1:
-			ereport(LOG,
-					(errmsg("could not fork archiver: %m")));
-			return 0;
-
-#ifndef EXEC_BACKEND
-		case 0:
-			/* in postmaster child ... */
-			InitPostmasterChild();
-
-			/* Close the postmaster's sockets */
-			ClosePostmasterPorts(false);
+	return size;
+}
 
-			/* Drop our connection to postmaster's shared memory, as well */
-			dsm_detach_all();
-			PGSharedMemoryDetach();
+/* Allocate and initialize archiver-related shared memory */
+void
+PgArchShmemInit(void)
+{
+	bool		found;
 
-			PgArchiverMain(0, NULL);
-			break;
-#endif
+	PgArch = (PgArchData *)
+		ShmemInitStruct("Archiver Data", PgArchShmemSize(), &found);
 
-		default:
-			return (int) pgArchPid;
+	if (!found)
+	{
+		/* First time through, so initialize */
+		MemSet(PgArch, 0, PgArchShmemSize());
+		PgArch->pgprocno = INVALID_PGPROCNO;
 	}
-
-	/* shouldn't get here */
-	return 0;
 }
 
-/* ------------------------------------------------------------
- * Local functions called by archiver follow
- * ------------------------------------------------------------
- */
-
-
-#ifdef EXEC_BACKEND
-
 /*
- * pgarch_forkexec() -
+ *  PgArchIsSuppressed
  *
- * Format up the arglist for, then fork and exec, archive process
+ * Return true if archiver relaunch is suppressed.
+ *
+ * This is a safety valve to protect against continuous respawn attempts if the
+ * archiver is dying immediately at launch. Note that since we will retry to
+ * launch the archiver from the postmaster main loop, we will get another
+ * chance later.
  */
-static pid_t
-pgarch_forkexec(void)
+bool
+PgArchCanRestart(void)
 {
-	char	   *av[10];
-	int			ac = 0;
-
-	av[ac++] = "postgres";
+	static time_t last_pgarch_start_time = 0;
+	time_t		curtime = time(NULL);
 
-	av[ac++] = "--forkarch";
-
-	av[ac++] = NULL;			/* filled in by postmaster_forkexec */
+	/*
+	 * allow to launch also for the first time and when something's wrong in
+	 * the time values.
+	 */
+	if (last_pgarch_start_time == 0 ||
+		curtime < last_pgarch_start_time ||
+		(curtime - last_pgarch_start_time) >= PGARCH_RESTART_INTERVAL)
+	{
+		last_pgarch_start_time = curtime;
 
-	av[ac] = NULL;
-	Assert(ac < lengthof(av));
+		return true;
+	}
 
-	return postmaster_forkexec(ac, av);
+	return false;
 }
-#endif							/* EXEC_BACKEND */
 
 
-/*
- * PgArchiverMain
- *
- *	The argc/argv parameters are valid only in EXEC_BACKEND case.  However,
- *	since we don't use 'em, it hardly matters...
- */
-NON_EXEC_STATIC void
-PgArchiverMain(int argc, char *argv[])
+/* Main entry point for archiver process */
+void
+PgArchiverMain(void)
 {
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
@@ -231,33 +177,51 @@ PgArchiverMain(int argc, char *argv[])
 	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, pgarch_waken);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
 	pqsignal(SIGUSR2, pgarch_waken_stop);
+
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
+
+	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
-	MyBackendType = B_ARCHIVER;
-	init_ps_display(NULL);
+	/* We shouldn't be launched unnecessarily. */
+	Assert(XLogArchivingActive());
+
+	/* Arrange to clean up at archiver exit */
+	on_shmem_exit(pgarch_die, 0);
+
+	/*
+	 * Advertise our pgproc index so that backends can use our latch to wake
+	 * us up while we're sleeping.
+	 */
+	PgArch->pgprocno = MyProc->pgprocno;
 
 	pgarch_MainLoop();
 
-	exit(0);
+	proc_exit(0);
 }
 
-/* SIGUSR1 signal handler for archiver process */
-static void
-pgarch_waken(SIGNAL_ARGS)
+/*
+ * Wake up the archiver
+ */
+void
+PgArchWakeup(void)
 {
-	int			save_errno = errno;
+	int			arch_pgprocno = PgArch->pgprocno;
 
-	/* set flag that there is work to be done */
-	wakened = true;
-	SetLatch(MyLatch);
-
-	errno = save_errno;
+	/*
+	 * We don't acquire ProcArrayLock here.  It's actually fine because
+	 * procLatch isn't ever freed, so we just can potentially set the wrong
+	 * process' (or no process') latch.  Even in that case the archiver will
+	 * be relaunched shortly and will start archiving.
+	 */
+	if (arch_pgprocno != INVALID_PGPROCNO)
+		SetLatch(&ProcGlobal->allProcs[arch_pgprocno].procLatch);
 }
 
+
 /* SIGUSR2 signal handler for archiver process */
 static void
 pgarch_waken_stop(SIGNAL_ARGS)
@@ -282,14 +246,6 @@ pgarch_MainLoop(void)
 	pg_time_t	last_copy_time = 0;
 	bool		time_to_stop;
 
-	/*
-	 * We run the copy loop immediately upon entry, in case there are
-	 * unarchived files left over from a previous database run (or maybe the
-	 * archiver died unexpectedly).  After that we wait for a signal or
-	 * timeout before doing more.
-	 */
-	wakened = true;
-
 	/*
 	 * There shouldn't be anything for the archiver to do except to wait for a
 	 * signal ... however, the archiver exists to protect our data, so she
@@ -328,12 +284,8 @@ pgarch_MainLoop(void)
 		}
 
 		/* Do what we're here for */
-		if (wakened || time_to_stop)
-		{
-			wakened = false;
-			pgarch_ArchiverCopyLoop();
-			last_copy_time = time(NULL);
-		}
+		pgarch_ArchiverCopyLoop();
+		last_copy_time = time(NULL);
 
 		/*
 		 * Sleep until a signal is received, or until a poll is forced by
@@ -354,13 +306,9 @@ pgarch_MainLoop(void)
 							   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 							   timeout * 1000L,
 							   WAIT_EVENT_ARCHIVER_MAIN);
-				if (rc & WL_TIMEOUT)
-					wakened = true;
 				if (rc & WL_POSTMASTER_DEATH)
 					time_to_stop = true;
 			}
-			else
-				wakened = true;
 		}
 
 		/*
@@ -744,3 +692,15 @@ pgarch_archiveDone(char *xlog)
 	StatusFilePath(rlogdone, xlog, ".done");
 	(void) durable_rename(rlogready, rlogdone, WARNING);
 }
+
+
+/*
+ * pgarch_die
+ *
+ * Exit-time cleanup handler
+ */
+static void
+pgarch_die(int code, Datum arg)
+{
+	PgArch->pgprocno = INVALID_PGPROCNO;
+}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index edab95a19e..e8af05c04e 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -443,9 +443,10 @@ static void InitPostmasterDeathWatchHandle(void);
  * even during recovery.
  */
 #define PgArchStartupAllowed()	\
-	((XLogArchivingActive() && pmState == PM_RUN) ||	\
-	 (XLogArchivingAlways() &&	\
-	  (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY)))
+	(((XLogArchivingActive() && pmState == PM_RUN) ||			\
+	  (XLogArchivingAlways() &&									  \
+	   (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY))) && \
+	 PgArchCanRestart())
 
 #ifdef EXEC_BACKEND
 
@@ -548,6 +549,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
 #endif							/* EXEC_BACKEND */
 
 #define StartupDataBase()		StartChildProcess(StartupProcess)
+#define StartArchiver()			StartChildProcess(ArchiverProcess)
 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
 #define StartCheckpointer()		StartChildProcess(CheckpointerProcess)
 #define StartWalWriter()		StartChildProcess(WalWriterProcess)
@@ -1792,7 +1794,7 @@ ServerLoop(void)
 
 		/* If we have lost the archiver, try to start a new one. */
 		if (PgArchPID == 0 && PgArchStartupAllowed())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/* If we need to signal the autovacuum launcher, do so now */
 		if (avlauncher_needs_signal)
@@ -3007,7 +3009,7 @@ reaper(SIGNAL_ARGS)
 			if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
 				AutoVacPID = StartAutoVacLauncher();
 			if (PgArchStartupAllowed() && PgArchPID == 0)
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			if (PgStatPID == 0)
 				PgStatPID = pgstat_start();
 
@@ -3142,20 +3144,22 @@ reaper(SIGNAL_ARGS)
 		}
 
 		/*
-		 * Was it the archiver?  If so, just try to start a new one; no need
-		 * to force reset of the rest of the system.  (If fail, we'll try
-		 * again in future cycles of the main loop.).  Unless we were waiting
-		 * for it to shut down; don't restart it in that case, and
+		 * Was it the archiver?  If exit status is zero (normal) or one (FATAL
+		 * exit), we assume everything is all right just like normal backends
+		 * and just try to restart a new one so that we immediately retry
+		 * archiving remaining files. (If fail, we'll try again in future
+		 * cycles of the postmaster's main loop.) Unless we were waiting for
+		 * it to shut down; don't restart it in that case, and
 		 * PostmasterStateMachine() will advance to the next shutdown step.
 		 */
 		if (pid == PgArchPID)
 		{
 			PgArchPID = 0;
-			if (!EXIT_STATUS_0(exitstatus))
-				LogChildExit(LOG, _("archiver process"),
-							 pid, exitstatus);
+			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
+				HandleChildCrash(pid, exitstatus,
+								 _("archiver process"));
 			if (PgArchStartupAllowed())
-				PgArchPID = pgarch_start();
+				PgArchPID = StartArchiver();
 			continue;
 		}
 
@@ -3403,7 +3407,7 @@ CleanupBackend(int pid,
 
 /*
  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
- * walwriter, autovacuum, or background worker.
+ * walwriter, autovacuum, archiver or background worker.
  *
  * The objectives here are to clean up our local state about the child
  * process, and to signal all other remaining children to quickdie.
@@ -3609,19 +3613,16 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 		signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
-	/*
-	 * Force a power-cycle of the pgarch process too.  (This isn't absolutely
-	 * necessary, but it seems like a good idea for robustness, and it
-	 * simplifies the state-machine logic in the case where a shutdown request
-	 * arrives during crash processing.)
-	 */
-	if (PgArchPID != 0 && take_action)
+	/* Take care of the archiver too */
+	if (pid == PgArchPID)
+		PgArchPID = 0;
+	else if (PgArchPID != 0 && take_action)
 	{
 		ereport(DEBUG2,
 				(errmsg_internal("sending %s to process %d",
-								 "SIGQUIT",
+								 (SendStop ? "SIGSTOP" : "SIGQUIT"),
 								 (int) PgArchPID)));
-		signal_child(PgArchPID, SIGQUIT);
+		signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT));
 	}
 
 	/*
@@ -3804,12 +3805,11 @@ PostmasterStateMachine(void)
 		 * (including autovac workers), no bgworkers (including unconnected
 		 * ones), and no walwriter, autovac launcher or bgwriter.  If we are
 		 * doing crash recovery or an immediate shutdown then we expect the
-		 * checkpointer to exit as well, otherwise not. The archiver, stats,
-		 * and syslogger processes are disregarded since they are not
-		 * connected to shared memory; we also disregard dead_end children
-		 * here. Walsenders are also disregarded, they will be terminated
-		 * later after writing the checkpoint record, like the archiver
-		 * process.
+		 * checkpointer to exit as well, otherwise not. The stats and
+		 * syslogger processes are disregarded since they are not connected to
+		 * shared memory; we also disregard dead_end children here. Walsenders
+		 * and archiver are also disregarded, they will be terminated later
+		 * after writing the checkpoint record.
 		 */
 		if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 &&
 			StartupPID == 0 &&
@@ -3912,6 +3912,7 @@ PostmasterStateMachine(void)
 			Assert(CheckpointerPID == 0);
 			Assert(WalWriterPID == 0);
 			Assert(AutoVacPID == 0);
+			Assert(PgArchPID == 0);
 			/* syslogger is not considered here */
 			pmState = PM_NO_CHILDREN;
 		}
@@ -5037,12 +5038,6 @@ SubPostmasterMain(int argc, char *argv[])
 
 		StartBackgroundWorker();
 	}
-	if (strcmp(argv[1], "--forkarch") == 0)
-	{
-		/* Do not want to attach to shared memory */
-
-		PgArchiverMain(argc, argv); /* does not return */
-	}
 	if (strcmp(argv[1], "--forkcol") == 0)
 	{
 		/* Do not want to attach to shared memory */
@@ -5140,7 +5135,7 @@ sigusr1_handler(SIGNAL_ARGS)
 		 */
 		Assert(PgArchPID == 0);
 		if (XLogArchivingAlways())
-			PgArchPID = pgarch_start();
+			PgArchPID = StartArchiver();
 
 		/*
 		 * If we aren't planning to enter hot standby mode later, treat
@@ -5194,16 +5189,6 @@ sigusr1_handler(SIGNAL_ARGS)
 	if (StartWorkerNeeded || HaveCrashedWorker)
 		maybe_start_bgworkers();
 
-	if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
-		PgArchPID != 0)
-	{
-		/*
-		 * Send SIGUSR1 to archiver process, to wake it up and begin archiving
-		 * next WAL file.
-		 */
-		signal_child(PgArchPID, SIGUSR1);
-	}
-
 	/* Tell syslogger to rotate logfile if requested */
 	if (SysLoggerPID != 0)
 	{
@@ -5445,6 +5430,10 @@ StartChildProcess(AuxProcType type)
 				ereport(LOG,
 						(errmsg("could not fork startup process: %m")));
 				break;
+			case ArchiverProcess:
+				ereport(LOG,
+						(errmsg("could not fork archiver process: %m")));
+				break;
 			case BgWriterProcess:
 				ereport(LOG,
 						(errmsg("could not fork background writer process: %m")));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index f9bbe97b50..3e4ec53a97 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -144,6 +144,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, ReplicationOriginShmemSize());
 		size = add_size(size, WalSndShmemSize());
 		size = add_size(size, WalRcvShmemSize());
+		size = add_size(size, PgArchShmemSize());
 		size = add_size(size, ApplyLauncherShmemSize());
 		size = add_size(size, SnapMgrShmemSize());
 		size = add_size(size, BTreeShmemSize());
@@ -258,6 +259,7 @@ CreateSharedMemoryAndSemaphores(void)
 	ReplicationOriginShmemInit();
 	WalSndShmemInit();
 	WalRcvShmemInit();
+	PgArchShmemInit();
 	ApplyLauncherShmemInit();
 
 	/*
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 54693e047a..013850ac28 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -417,6 +417,7 @@ typedef enum
 	BootstrapProcess,
 	StartupProcess,
 	BgWriterProcess,
+	ArchiverProcess,
 	CheckpointerProcess,
 	WalWriterProcess,
 	WalReceiverProcess,
@@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType;
 #define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
+#define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)
 #define AmCheckpointerProcess()		(MyAuxProcType == CheckpointerProcess)
 #define AmWalWriterProcess()		(MyAuxProcType == WalWriterProcess)
 #define AmWalReceiverProcess()		(MyAuxProcType == WalReceiverProcess)
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index d102a21ab7..1e47a143e1 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -26,14 +26,10 @@
 #define MAX_XFN_CHARS	40
 #define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
 
-/* ----------
- * Functions called from postmaster
- * ----------
- */
-extern int	pgarch_start(void);
-
-#ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn();
-#endif
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern bool PgArchCanRestart(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
 
 #endif							/* _PGARCH_H */
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h
index dbbed18f61..8ed4d87ae6 100644
--- a/src/include/storage/pmsignal.h
+++ b/src/include/storage/pmsignal.h
@@ -34,7 +34,6 @@ typedef enum
 {
 	PMSIGNAL_RECOVERY_STARTED,	/* recovery has started */
 	PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
-	PMSIGNAL_WAKEN_ARCHIVER,	/* send a NOTIFY signal to xlog archiver */
 	PMSIGNAL_ROTATE_LOGFILE,	/* send SIGUSR1 to syslogger to rotate logfile */
 	PMSIGNAL_START_AUTOVAC_LAUNCHER,	/* start an autovacuum launcher */
 	PMSIGNAL_START_AUTOVAC_WORKER,	/* start an autovacuum worker */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index a777cb64a1..2fd1ff09a7 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -370,11 +370,11 @@ extern PGPROC *PreparedXactProcs;
  * We set aside some extra PGPROC structures for auxiliary processes,
  * ie things that aren't full-fledged backends but need shmem access.
  *
- * Background writer, checkpointer and WAL writer run during normal operation.
- * Startup process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 4 slots.
+ * Background writer, checkpointer, WAL writer and archiver run during normal
+ * operation.  Startup process and WAL receiver also consume 2 slots, but WAL
+ * writer is launched only after startup has exited, so we only need 5 slots.
  */
-#define NUM_AUXILIARY_PROCS		4
+#define NUM_AUXILIARY_PROCS		5
 
 /* configurable options */
 extern PGDLLIMPORT int DeadlockTimeout;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 99a34be465..78e852569e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1572,6 +1572,7 @@ PGresAttValue
 PGresParamDesc
 PGresult
 PGresult_data
+PgArchData
 PHANDLE
 PLAINTREE
 PLUID_AND_ATTRIBUTES
-- 
2.27.0


----Next_Part(Fri_Mar_12_17_24_43_2021_866)----





^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* pgsql: Delay commit status checks until freezing executes.
@ 2023-01-03 19:23  Peter Geoghegan <[email protected]>
  0 siblings, 1 reply; 279+ messages in thread

From: Peter Geoghegan @ 2023-01-03 19:23 UTC (permalink / raw)
  To: [email protected]

Delay commit status checks until freezing executes.

pg_xact lookups are relatively expensive.  Move the xmin/xmax commit
status checks from the point that freeze plans are prepared to the point
that they're actually executed.  Otherwise we'll repeat many commit
status checks whenever multiple successive VACUUM operations scan the
same pages and decide against freezing each time, which is a waste of
cycles.

Oversight in commit 1de58df4, which added page-level freezing.

Author: Peter Geoghegan <[email protected]>
Discussion: https://postgr.es/m/CAH2-WzkZpe4K6qMfEt8H4qYJCKc2R7TPvKsBva7jc9w7iGXQSw@mail.gmail.com

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/79d4bf4eff14d8967b10ad4c60039c1b9b0cf66e

Modified Files
--------------
src/backend/access/heap/heapam.c | 89 ++++++++++++++++++++++++++++------------
src/include/access/heapam.h      |  9 ++++
2 files changed, 71 insertions(+), 27 deletions(-)



^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* Re: pgsql: Delay commit status checks until freezing executes.
@ 2023-01-04 00:54  Andres Freund <[email protected]>
  parent: Peter Geoghegan <[email protected]>
  0 siblings, 1 reply; 279+ messages in thread

From: Andres Freund @ 2023-01-04 00:54 UTC (permalink / raw)
  To: Peter Geoghegan <[email protected]>; pgsql-hackers; +Cc: [email protected]

Hi,

On 2023-01-03 19:23:41 +0000, Peter Geoghegan wrote:
> Delay commit status checks until freezing executes.
> 
> pg_xact lookups are relatively expensive.  Move the xmin/xmax commit
> status checks from the point that freeze plans are prepared to the point
> that they're actually executed.  Otherwise we'll repeat many commit
> status checks whenever multiple successive VACUUM operations scan the
> same pages and decide against freezing each time, which is a waste of
> cycles.
> 
> Oversight in commit 1de58df4, which added page-level freezing.
> 
> Author: Peter Geoghegan <[email protected]>
> Discussion: https://postgr.es/m/CAH2-WzkZpe4K6qMfEt8H4qYJCKc2R7TPvKsBva7jc9w7iGXQSw@mail.gmail.com

There's some changes from TransactionIdDidCommit() to !TransactionIdDidAbort()
that don't look right to me. If the server crashed while xid X was
in-progress, TransactionIdDidCommit(X) will return false, but so will
TransactionIdDidAbort(X). So besides moving when the check happens you also
changed what's being checked in a more substantial way.


Also, why did you change when MarkBufferDirty() happens? Previously it
happened before we modify the page contents, now after. That's probably fine
(it's the order suggested in transam/README), but seems like a mighty subtle
thing to change at the same time as something unrelated, particularly without
even mentioning it?


Greetings,

Andres Freund






^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* Re: pgsql: Delay commit status checks until freezing executes.
@ 2023-01-04 01:15  Peter Geoghegan <[email protected]>
  parent: Andres Freund <[email protected]>
  0 siblings, 1 reply; 279+ messages in thread

From: Peter Geoghegan @ 2023-01-04 01:15 UTC (permalink / raw)
  To: Andres Freund <[email protected]>; +Cc: pgsql-hackers; [email protected]

On Tue, Jan 3, 2023 at 4:54 PM Andres Freund <[email protected]> wrote:
> There's some changes from TransactionIdDidCommit() to !TransactionIdDidAbort()
> that don't look right to me. If the server crashed while xid X was
> in-progress, TransactionIdDidCommit(X) will return false, but so will
> TransactionIdDidAbort(X). So besides moving when the check happens you also
> changed what's being checked in a more substantial way.

I did point this out on the thread. I made this change with the
intention of making the check more robust. Apparently this was
misguided.

Where is the behavior that you describe documented, if anywhere?

> Also, why did you change when MarkBufferDirty() happens? Previously it
> happened before we modify the page contents, now after. That's probably fine
> (it's the order suggested in transam/README), but seems like a mighty subtle
> thing to change at the same time as something unrelated, particularly without
> even mentioning it?

I changed it because the new order is idiomatic. I didn't think that
this was particularly worth mentioning, or even subtle. The logic from
heap_execute_freeze_tuple() only performs simple in-place
modifications.

-- 
Peter Geoghegan






^ permalink  raw  reply  [nested|flat] 279+ messages in thread

* Re: pgsql: Delay commit status checks until freezing executes.
@ 2023-01-04 01:54  Peter Geoghegan <[email protected]>
  parent: Peter Geoghegan <[email protected]>
  0 siblings, 0 replies; 279+ messages in thread

From: Peter Geoghegan @ 2023-01-04 01:54 UTC (permalink / raw)
  To: Andres Freund <[email protected]>; +Cc: pgsql-hackers

(Pruning -committers from the list, since cross-posting to -hackers
resulted in this being held up for moderation.)

On Tue, Jan 3, 2023 at 5:15 PM Peter Geoghegan <[email protected]> wrote:
>
> On Tue, Jan 3, 2023 at 4:54 PM Andres Freund <[email protected]> wrote:
> > There's some changes from TransactionIdDidCommit() to !TransactionIdDidAbort()
> > that don't look right to me. If the server crashed while xid X was
> > in-progress, TransactionIdDidCommit(X) will return false, but so will
> > TransactionIdDidAbort(X). So besides moving when the check happens you also
> > changed what's being checked in a more substantial way.
>
> I did point this out on the thread. I made this change with the
> intention of making the check more robust. Apparently this was
> misguided.
>
> Where is the behavior that you describe documented, if anywhere?

When the server crashes, and we have a problem case, what does
TransactionLogFetch()/TransactionIdGetStatus() (which are the guts of
both TransactionIdDidCommit and TransactionIdDidAbort) report about
the XID?

> > Also, why did you change when MarkBufferDirty() happens? Previously it
> > happened before we modify the page contents, now after. That's probably fine
> > (it's the order suggested in transam/README), but seems like a mighty subtle
> > thing to change at the same time as something unrelated, particularly without
> > even mentioning it?
>
> I changed it because the new order is idiomatic. I didn't think that
> this was particularly worth mentioning, or even subtle. The logic from
> heap_execute_freeze_tuple() only performs simple in-place
> modifications.

I'm including this here because presumably -hackers will have missed
it due to the moderation hold-up issue.


--
Peter Geoghegan






^ permalink  raw  reply  [nested|flat] 279+ messages in thread


end of thread, other threads:[~2023-01-04 01:54 UTC | newest]

Thread overview: 279+ messages (download: mbox mbox.gz follow: Atom feed)
-- links below jump to the message on this page --
2018-11-07 07:53 [PATCH v24 3/5] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2018-11-07 07:53 [PATCH 3/5] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v47 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v50 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v50 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v51 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v46 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v51 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v50 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v46 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v52 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v37 3/6] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v50 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v50 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v46 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v52 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v47 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v49 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v47 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v50 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v49 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v47 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v46 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v30 4/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v49 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v49 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v45 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v50 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v50 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v52 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v49 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v48 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v51 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v49 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v45 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v45 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v49 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v47 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v45 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v45 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v52 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v48 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v46 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v47 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v51 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v46 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v47 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v48 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v51 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v48 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v50 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v52 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v48 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v51 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v49 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v49 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v41 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v47 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v46 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v38 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v49 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v52 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v48 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v52 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v47 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v45 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v48 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v35 4/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v47 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v52 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v49 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v51 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v48 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v45 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v50 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v33 4/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v51 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v50 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v48 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v42 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v45 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v47 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v52 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v48 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v48 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v45 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v50 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v46 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v40 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v46 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v47 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v49 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v48 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v45 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v51 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v45 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v52 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v50 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v49 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v52 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v45 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v51 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v51 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v47 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v47 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v50 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v46 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v49 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v49 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v52 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v52 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v45 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v46 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v46 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v51 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v48 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v51 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v51 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v46 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v45 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v31 4/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v45 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v50 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v50 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v45 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v51 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v50 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v46 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v46 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v49 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v48 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v49 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v52 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v46 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v48 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v49 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v50 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v47 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v48 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v25 4/8] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v48 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v52 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v50 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v45 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v51 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v46 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v29 4/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v49 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v52 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v49 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v52 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v48 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v50 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v48 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v32 4/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v49 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v34 4/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v49 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v48 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v50 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v51 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v51 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v49 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v36 4/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v47 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v45 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v51 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v51 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v50 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v50 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v52 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v47 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v51 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v51 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v52 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v48 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v51 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v48 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v52 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v46 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v43 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v49 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v44 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v47 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v51 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v52 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v45 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v46 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v48 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v52 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v45 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v47 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v46 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v33 4/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v52 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v52 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v48 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v39 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v47 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v47 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v50 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v45 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2020-03-13 07:59 [PATCH v46 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v53 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v53 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v55 3/3] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v53 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v54 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v53 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v54 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v54 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v53 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v55 3/3] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v55 3/3] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v54 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v54 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v55 3/3] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v54 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v53 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v54 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v53 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v53 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v53 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v53 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v54 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v54 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v53 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v55 3/3] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v55 3/3] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v53 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v55 3/3] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v55 3/3] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v55 3/3] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v54 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v55 3/3] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v53 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v53 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v55 3/3] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v55 3/3] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v54 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v55 3/3] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v53 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v55 3/3] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v54 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v54 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v53 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v53 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v53 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v55 3/3] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v54 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v55 3/3] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v54 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v53 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v55 3/3] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v55 3/3] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v53 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v54 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v55 3/3] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v54 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v53 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v55 3/3] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v54 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v55 3/3] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v54 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v54 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v55 3/3] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v55 3/3] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v54 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v54 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v53 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v54 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v54 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v53 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v53 3/7] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2021-03-11 09:01 [PATCH v55 3/3] Make archiver process an auxiliary process Kyotaro Horiguchi <[email protected]>
2023-01-03 19:23 pgsql: Delay commit status checks until freezing executes. Peter Geoghegan <[email protected]>
2023-01-04 00:54 ` Re: pgsql: Delay commit status checks until freezing executes. Andres Freund <[email protected]>
2023-01-04 01:15   ` Re: pgsql: Delay commit status checks until freezing executes. Peter Geoghegan <[email protected]>
2023-01-04 01:54     ` Re: pgsql: Delay commit status checks until freezing executes. Peter Geoghegan <[email protected]>

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