Fix assorted pretty-trivial memory leaks in the backend.

In the current system architecture, none of these are worth obsessing
over; most are once-per-process leaks.  However, Valgrind complains
about all of them, and if we get to using threads rather than
processes for backend sessions, it will become more interesting to
avoid per-session leaks.

* Fix leaks in StartupXLOG() and ShutdownWalRecovery().

* Fix leakage of pq_mq_handle in a parallel worker.
While at it, move mq_putmessage's "Assert(pq_mq_handle != NULL)"
to someplace where it's not trivially useless.

* Fix leak in logicalrep_worker_detach().

* Don't leak the startup-packet buffer in ProcessStartupPacket().

* Fix leak in evtcache.c's DecodeTextArrayToBitmapset().
If the presented array is toasted, this neglected to free the
detoasted copy, which was then leaked into EventTriggerCacheContext.

* I'm distressed by the amount of code that BuildEventTriggerCache
is willing to run while switched into a long-lived cache context.
Although the detoasted array is the only leak that Valgrind reports,
let's tighten things up while we're here.  (DecodeTextArrayToBitmapset
is still run in the cache context, so doing this doesn't remove the
need for the detoast fix.  But it reduces the surface area for other
leaks.)

* load_domaintype_info() intentionally leaked some intermediate cruft
into the long-lived DomainConstraintCache's memory context, reasoning
that the amount of leakage will typically not be much so it's not
worth doing a copyObject() of the final tree to avoid that.  But
Valgrind knows nothing of engineering tradeoffs and complains anyway.
On the whole, the copyObject doesn't cost that much and this is surely
not a performance-critical code path, so let's do it the clean way.

* MarkGUCPrefixReserved didn't bother to clean up removed placeholder
GUCs at all, which shows up as a leak in one regression test.
It seems appropriate for it to do as much cleanup as
define_custom_variable does when replacing placeholders, so factor
that code out into a helper function.  define_custom_variable's logic
was one brick shy of a load too: it forgot to free the separate
allocation for the placeholder's name.

Author: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Andres Freund <andres@anarazel.de>
Reviewed-by: Richard Guo <guofenglinux@gmail.com>
Discussion: https://postgr.es/m/285483.1746756246@sss.pgh.pa.us

1 files changed, 22 insertions, 11 deletions

diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index b0891998b24..5553c20fee8 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -703,7 +703,7 @@ static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
 static void WriteControlFile(void);
 static void ReadControlFile(void);
 static void UpdateControlFile(void);
-static char *str_time(pg_time_t tnow);
+static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
 
 static int	get_sync_bit(int method);
 
@@ -5371,11 +5371,9 @@ BootStrapXLOG(uint32 data_checksum_version)
 }
 
 static char *
-str_time(pg_time_t tnow)
+str_time(pg_time_t tnow, char *buf, size_t bufsize)
 {
-	char	   *buf = palloc(128);
-
-	pg_strftime(buf, 128,
+	pg_strftime(buf, bufsize,
 				"%Y-%m-%d %H:%M:%S %Z",
 				pg_localtime(&tnow, log_timezone));
 
@@ -5618,6 +5616,7 @@ StartupXLOG(void)
 	XLogRecPtr	missingContrecPtr;
 	TransactionId oldestActiveXID;
 	bool		promoted = false;
+	char		timebuf[128];
 
 	/*
 	 * We should have an aux process resource owner to use, and we should not
@@ -5646,25 +5645,29 @@ StartupXLOG(void)
 			 */
 			ereport(IsPostmasterEnvironment ? LOG : NOTICE,
 					(errmsg("database system was shut down at %s",
-							str_time(ControlFile->time))));
+							str_time(ControlFile->time,
+									 timebuf, sizeof(timebuf)))));
 			break;
 
 		case DB_SHUTDOWNED_IN_RECOVERY:
 			ereport(LOG,
 					(errmsg("database system was shut down in recovery at %s",
-							str_time(ControlFile->time))));
+							str_time(ControlFile->time,
+									 timebuf, sizeof(timebuf)))));
 			break;
 
 		case DB_SHUTDOWNING:
 			ereport(LOG,
 					(errmsg("database system shutdown was interrupted; last known up at %s",
-							str_time(ControlFile->time))));
+							str_time(ControlFile->time,
+									 timebuf, sizeof(timebuf)))));
 			break;
 
 		case DB_IN_CRASH_RECOVERY:
 			ereport(LOG,
 					(errmsg("database system was interrupted while in recovery at %s",
-							str_time(ControlFile->time)),
+							str_time(ControlFile->time,
+									 timebuf, sizeof(timebuf))),
 					 errhint("This probably means that some data is corrupted and"
 							 " you will have to use the last backup for recovery.")));
 			break;
@@ -5672,7 +5675,8 @@ StartupXLOG(void)
 		case DB_IN_ARCHIVE_RECOVERY:
 			ereport(LOG,
 					(errmsg("database system was interrupted while in recovery at log time %s",
-							str_time(ControlFile->checkPointCopy.time)),
+							str_time(ControlFile->checkPointCopy.time,
+									 timebuf, sizeof(timebuf))),
 					 errhint("If this has occurred more than once some data might be corrupted"
 							 " and you might need to choose an earlier recovery target.")));
 			break;
@@ -5680,7 +5684,8 @@ StartupXLOG(void)
 		case DB_IN_PRODUCTION:
 			ereport(LOG,
 					(errmsg("database system was interrupted; last known up at %s",
-							str_time(ControlFile->time))));
+							str_time(ControlFile->time,
+									 timebuf, sizeof(timebuf)))));
 			break;
 
 		default:
@@ -6325,6 +6330,12 @@ StartupXLOG(void)
 	 */
 	CompleteCommitTsInitialization();
 
+	/* Clean up EndOfWalRecoveryInfo data to appease Valgrind leak checking */
+	if (endOfRecoveryInfo->lastPage)
+		pfree(endOfRecoveryInfo->lastPage);
+	pfree(endOfRecoveryInfo->recoveryStopReason);
+	pfree(endOfRecoveryInfo);
+
 	/*
 	 * All done with end-of-recovery actions.
 	 *