postgres.git / summary / log / commit / refs

commit    b9cf9d7d3bede9e86e75a5b093d76e1dddcbd084
Author:   Fujii Masao <fujii@postgresql.org>
Date:     Mon Apr 05 17:25:37 2021 +0000
First released in: 14.0, 9.6.22, 10.17, 11.12, 12.7, 13.3

    Shut down transaction tracking at startup process exit.
    
    Maxim Orlov reported that the shutdown of standby server could result in
    the following assertion failure. The cause of this issue was that,
    when the shutdown caused the startup process to exit, recovery-time
    transaction tracking was not shut down even if it's already initialized,
    and some locks the tracked transactions were holding could not be released.
    At this situation, if other process was invoked and the PGPROC entry that
    the startup process used was assigned to it, it found such unreleased locks
    and caused the assertion failure, during the initialization of it.
    
        TRAP: FailedAssertion("SHMQueueEmpty(&(MyProc->myProcLocks[i]))"
    
    This commit fixes this issue by making the startup process shut down
    transaction tracking and release all locks, at the exit of it.
    
    Back-patch to all supported branches.
    
    Reported-by: Maxim Orlov
    Author: Fujii Masao
    Reviewed-by: Maxim Orlov
    Discussion: https://postgr.es/m/ad4ce692cc1d89a093b471ab1d969b0b@postgrespro.ru


 src/backend/postmaster/startup.c  | 19 +++++++++++++++++++
 src/backend/storage/ipc/standby.c | 15 +++++++++++++++
 2 files changed, 34 insertions(+)

diff --git a/src/backend/postmaster/startup.c b/src/backend/postmaster/startup.c
index 4734c369308..a26428a7ea6 100644
--- a/src/backend/postmaster/startup.c
+++ b/src/backend/postmaster/startup.c
@@ -54,6 +54,9 @@ static void StartupProcSigUsr1Handler(SIGNAL_ARGS);
 static void StartupProcTriggerHandler(SIGNAL_ARGS);
 static void StartupProcSigHupHandler(SIGNAL_ARGS);
 
+/* Callbacks */
+static void StartupProcExit(int code, Datum arg);
+
 
 /* --------------------------------
  *		signal handler routines
@@ -165,6 +168,19 @@ HandleStartupProcInterrupts(void)
 }
 
 
+/* --------------------------------
+ *		signal handler routines
+ * --------------------------------
+ */
+static void
+StartupProcExit(int code, Datum arg)
+{
+	/* Shutdown the recovery environment */
+	if (standbyState != STANDBY_DISABLED)
+		ShutdownRecoveryTransactionEnvironment();
+}
+
+
 /* ----------------------------------
  *	Startup Process main entry point
  * ----------------------------------
@@ -172,6 +188,9 @@ HandleStartupProcInterrupts(void)
 void
 StartupProcessMain(void)
 {
+	/* Arrange to clean up at startup process exit */
+	on_shmem_exit(StartupProcExit, 0);
+
 	/*
 	 * Properly accept or ignore signals the postmaster might send us.
 	 */
diff --git a/src/backend/storage/ipc/standby.c b/src/backend/storage/ipc/standby.c
index a65b12861ff..863cb641007 100644
--- a/src/backend/storage/ipc/standby.c
+++ b/src/backend/storage/ipc/standby.c
@@ -124,10 +124,25 @@ InitRecoveryTransactionEnvironment(void)
  *
  * Prepare to switch from hot standby mode to normal operation. Shut down
  * recovery-time transaction tracking.
+ *
+ * This must be called even in shutdown of startup process if transaction
+ * tracking has been initialized. Otherwise some locks the tracked
+ * transactions were holding will not be released and and may interfere with
+ * the processes still running (but will exit soon later) at the exit of
+ * startup process.
  */
 void
 ShutdownRecoveryTransactionEnvironment(void)
 {
+	/*
+	 * Do nothing if RecoveryLockLists is NULL because which means that
+	 * transaction tracking has not been yet initialized or has been already
+	 * shutdowned. This prevents transaction tracking from being shutdowned
+	 * unexpectedly more than once.
+	 */
+	if (RecoveryLockLists == NULL)
+		return;
+
 	/* Mark all tracked in-progress transactions as finished. */
 	ExpireAllKnownAssignedTransactionIds();
 


[parent: b4c3a9f32058]