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From: Kyotaro Horiguchi <[email protected]>
Subject: [PATCH v25 5/8] Use latch instead of SIGUSR1 to wake up archiver
Date: Mon, 16 Mar 2020 22:30:41 +0900

This is going to be combined into the archiver patch just before.
---
 src/backend/access/transam/xlog.c        | 49 ++++++++++++++++++++++++
 src/backend/access/transam/xlogarchive.c |  2 +-
 src/backend/postmaster/pgarch.c          | 27 ++++++-------
 src/backend/postmaster/postmaster.c      | 10 -----
 src/include/access/xlog.h                |  2 +
 src/include/access/xlog_internal.h       |  1 +
 src/include/storage/pmsignal.h           |  1 -
 7 files changed, 65 insertions(+), 27 deletions(-)

diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 4fa446ffa4..5c477211e9 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -668,6 +668,13 @@ 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
@@ -8359,6 +8366,48 @@ GetLastSegSwitchData(XLogRecPtr *lastSwitchLSN)
 	return result;
 }
 
+/*
+ * XLogArchiveWakeupEnd - Set up archiver wakeup stuff
+ */
+void
+XLogArchiveWakeupStart(void)
+{
+	Latch *old_latch PG_USED_FOR_ASSERTS_ONLY;
+	
+	SpinLockAcquire(&XLogCtl->info_lck);
+	old_latch = XLogCtl->archiverWakeupLatch;
+	XLogCtl->archiverWakeupLatch = MyLatch;
+	SpinLockRelease(&XLogCtl->info_lck);
+	Assert (old_latch == NULL);
+}
+
+/*
+ * 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 188b73e752..cedf969812 100644
--- a/src/backend/access/transam/xlogarchive.c
+++ b/src/backend/access/transam/xlogarchive.c
@@ -535,7 +535,7 @@ 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/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index 4971b3ae42..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"
 
@@ -94,7 +95,6 @@ static volatile sig_atomic_t ready_to_stop = false;
 static pid_t pgarch_forkexec(void);
 #endif
 
-static void pgarch_waken(SIGNAL_ARGS);
 static void pgarch_waken_stop(SIGNAL_ARGS);
 static void pgarch_MainLoop(void);
 static void pgarch_ArchiverCopyLoop(void);
@@ -141,6 +141,13 @@ pgarch_forkexec(void)
 #endif							/* EXEC_BACKEND */
 
 
+/* Clean up notification stuff on exit */
+static void
+PgArchiverKill(int code, Datum arg)
+{
+	XLogArchiveWakeupEnd();
+}
+
 /*
  * PgArchiverMain
  *
@@ -160,7 +167,7 @@ PgArchiverMain(void)
 	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);
@@ -169,24 +176,14 @@ PgArchiverMain(void)
 	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 cab7fb5381..fab4a9dd51 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -5262,16 +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)
 	{
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 98b033fc20..59e2f0f95a 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -311,6 +311,8 @@ 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 CheckPromoteSignal(void);
diff --git a/src/include/access/xlog_internal.h b/src/include/access/xlog_internal.h
index 27ded593ab..a272d62b1f 100644
--- a/src/include/access/xlog_internal.h
+++ b/src/include/access/xlog_internal.h
@@ -331,6 +331,7 @@ 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/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(Thu_Mar_19_20_30_04_2020_284)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
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 filename="v25-0006-Shared-memory-based-stats-collector.patch"



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