[CF 5611] v7 - SQL function which allows to distinguish a server being in point in time recovery mode and an ordinary replica

This branch was automatically generated by a robot using patches from an
email thread registered at:

https://commitfest.postgresql.org/patch/5611

The branch will be overwritten each time a new patch version is posted to
the thread, and also periodically to check for bitrot caused by changes
on the master branch.

Patch(es): https://www.postgresql.org/message-id/743b8aa9c532ae604a948cf9d6192839@postgrespro.ru
Author(s): Mikhail Litsarev

Author: Commitfest Bot

src/backend/access/transam/timeline.c

@@ -93,7 +93,7 @@ readTimeLineHistory(TimeLineID targetTLI)
 		return list_make1(entry);
 	}
 
-	if (ArchiveRecoveryRequested)
+	if (ArchiveRecoveryRequested())
 	{
 		TLHistoryFileName(histfname, targetTLI);
 		fromArchive =
@@ -229,7 +229,7 @@ existsTimeLineHistory(TimeLineID probeTLI)
 	if (probeTLI == 1)
 		return false;
 
-	if (ArchiveRecoveryRequested)
+	if (ArchiveRecoveryRequested())
 	{
 		TLHistoryFileName(histfname, probeTLI);
 		RestoreArchivedFile(path, histfname, "RECOVERYHISTORY", 0, false);
@@ -331,7 +331,7 @@ writeTimeLineHistory(TimeLineID newTLI, TimeLineID parentTLI,
 	/*
 	 * If a history file exists for the parent, copy it verbatim
 	 */
-	if (ArchiveRecoveryRequested)
+	if (ArchiveRecoveryRequested())
 	{
 		TLHistoryFileName(histfname, parentTLI);
 		RestoreArchivedFile(path, histfname, "RECOVERYHISTORY", 0, false);

src/backend/access/transam/xlog.c

@@ -5573,7 +5573,7 @@ CheckRequiredParameterValues(void)
 	 * For archive recovery, the WAL must be generated with at least 'replica'
 	 * wal_level.
 	 */
-	if (ArchiveRecoveryRequested && ControlFile->wal_level == WAL_LEVEL_MINIMAL)
+	if (ArchiveRecoveryRequested() && ControlFile->wal_level == WAL_LEVEL_MINIMAL)
 	{
 		ereport(FATAL,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
@@ -5586,7 +5586,7 @@ CheckRequiredParameterValues(void)
 	 * For Hot Standby, the WAL must be generated with 'replica' mode, and we
 	 * must have at least as many backend slots as the primary.
 	 */
-	if (ArchiveRecoveryRequested && EnableHotStandby)
+	if (ArchiveRecoveryRequested() && EnableHotStandby)
 	{
 		/* We ignore autovacuum_worker_slots when we make this test. */
 		RecoveryRequiresIntParameter("max_connections",
@@ -5746,8 +5746,8 @@ StartupXLOG(void)
 	 *
 	 * InitWalRecovery analyzes the control file and the backup label file, if
 	 * any.  It updates the in-memory ControlFile buffer according to the
-	 * starting checkpoint, and sets InRecovery and ArchiveRecoveryRequested.
-	 * It also applies the tablespace map file, if any.
+	 * starting checkpoint, and sets SX_ARCHIVE_RECOVERY_REQUESTED and
+	 * InRecovery. It also applies the tablespace map file, if any.
 	 */
 	InitWalRecovery(ControlFile, &wasShutdown,
 					&haveBackupLabel, &haveTblspcMap);
@@ -5879,7 +5879,7 @@ StartupXLOG(void)
 	{
 		/* Initialize state for RecoveryInProgress() */
 		SpinLockAcquire(&XLogCtl->info_lck);
-		if (InArchiveRecovery)
+		if (InArchiveRecovery())
 			XLogCtl->SharedRecoveryState = RECOVERY_STATE_ARCHIVE;
 		else
 			XLogCtl->SharedRecoveryState = RECOVERY_STATE_CRASH;
@@ -5932,7 +5932,7 @@ StartupXLOG(void)
 		 * startup process to think that there are still invalid page
 		 * references when checking for data consistency.
 		 */
-		if (InArchiveRecovery)
+		if (InArchiveRecovery())
 		{
 			LocalMinRecoveryPoint = ControlFile->minRecoveryPoint;
 			LocalMinRecoveryPointTLI = ControlFile->minRecoveryPointTLI;
@@ -5966,7 +5966,7 @@ StartupXLOG(void)
 		 * control file and we've established a recovery snapshot from a
 		 * running-xacts WAL record.
 		 */
-		if (ArchiveRecoveryRequested && EnableHotStandby)
+		if (ArchiveRecoveryRequested() && EnableHotStandby)
 		{
 			TransactionId *xids;
 			int			nxids;
@@ -6079,7 +6079,7 @@ StartupXLOG(void)
 		 * recover from an online backup but never called pg_backup_stop(), or
 		 * you didn't archive all the WAL needed.
 		 */
-		if (ArchiveRecoveryRequested || ControlFile->backupEndRequired)
+		if (ArchiveRecoveryRequested() || ControlFile->backupEndRequired)
 		{
 			if (!XLogRecPtrIsInvalid(ControlFile->backupStartPoint) || ControlFile->backupEndRequired)
 				ereport(FATAL,
@@ -6131,7 +6131,7 @@ StartupXLOG(void)
 	 * In a normal crash recovery, we can just extend the timeline we were in.
 	 */
 	newTLI = endOfRecoveryInfo->lastRecTLI;
-	if (ArchiveRecoveryRequested)
+	if (ArchiveRecoveryRequested())
 	{
 		newTLI = findNewestTimeLine(recoveryTargetTLI) + 1;
 		ereport(LOG,
@@ -6327,7 +6327,7 @@ StartupXLOG(void)
 	XLogReportParameters();
 
 	/* If this is archive recovery, perform post-recovery cleanup actions. */
-	if (ArchiveRecoveryRequested)
+	if (ArchiveRecoveryRequested())
 		CleanupAfterArchiveRecovery(EndOfLogTLI, EndOfLog, newTLI);
 
 	/*
@@ -6486,7 +6486,7 @@ PerformRecoveryXLogAction(void)
 	 * of a full checkpoint. A checkpoint is requested later, after we're
 	 * fully out of recovery mode and already accepting queries.
 	 */
-	if (ArchiveRecoveryRequested && IsUnderPostmaster &&
+	if (ArchiveRecoveryRequested() && IsUnderPostmaster &&
 		PromoteIsTriggered())
 	{
 		promoted = true;
@@ -8480,7 +8480,7 @@ xlog_redo(XLogReaderState *record)
 		 * record, the backup was canceled and the end-of-backup record will
 		 * never arrive.
 		 */
-		if (ArchiveRecoveryRequested &&
+		if (ArchiveRecoveryRequested() &&
 			!XLogRecPtrIsInvalid(ControlFile->backupStartPoint) &&
 			XLogRecPtrIsInvalid(ControlFile->backupEndPoint))
 			ereport(PANIC,
@@ -8721,7 +8721,7 @@ xlog_redo(XLogReaderState *record)
 		 * local copies cannot be updated as long as crash recovery is
 		 * happening and we expect all the WAL to be replayed.
 		 */
-		if (InArchiveRecovery)
+		if (InArchiveRecovery())
 		{
 			LocalMinRecoveryPoint = ControlFile->minRecoveryPoint;
 			LocalMinRecoveryPointTLI = ControlFile->minRecoveryPointTLI;

src/backend/access/transam/xlogarchive.c

@@ -68,7 +68,7 @@ RestoreArchivedFile(char *path, const char *xlogfname,
 	 * Ignore restore_command when not in archive recovery (meaning we are in
 	 * crash recovery).
 	 */
-	if (!ArchiveRecoveryRequested)
+	if (!ArchiveRecoveryRequested())
 		goto not_available;
 
 	/* In standby mode, restore_command might not be supplied */
@@ -205,7 +205,7 @@ RestoreArchivedFile(char *path, const char *xlogfname,
 				 * incorrectly conclude we've reached the end of WAL and we're
 				 * done recovering ...
 				 */
-				if (StandbyMode && stat_buf.st_size < expectedSize)
+				if (InStandbyMode() && stat_buf.st_size < expectedSize)
 					elevel = DEBUG1;
 				else
 					elevel = FATAL;

src/backend/access/transam/xlogfuncs.c

@@ -30,6 +30,7 @@
 #include "storage/fd.h"
 #include "storage/latch.h"
 #include "storage/standby.h"
+#include "utils/array.h"
 #include "utils/builtins.h"
 #include "utils/memutils.h"
 #include "utils/pg_lsn.h"
@@ -748,3 +749,33 @@ pg_promote(PG_FUNCTION_ARGS)
 						   wait_seconds)));
 	PG_RETURN_BOOL(false);
 }
+
+Datum
+pg_get_recovery_flags(PG_FUNCTION_ARGS)
+{
+/*
+ * Currently supported number of recovery flags is equal to two:
+ * {SX_PROMOTE_IS_TRIGGERED, SX_STANDBY_MODE_REQUESTED}.
+ * The SX_STANDBY_MODE_REQUESTED is valid only in the startup process.
+ */
+#define MAX_RECOVERY_FLAGS 2
+
+	bits32			recovery_flags;
+	int				cnt = 0;
+	Datum			flags[MAX_RECOVERY_FLAGS];
+	ArrayType	   *txt_arr;
+
+	recovery_flags = GetXLogRecoveryFlags();
+
+	if (recovery_flags & SX_PROMOTE_IS_TRIGGERED)
+		flags[cnt++] = CStringGetTextDatum("PROMOTE_IS_TRIGGERED");
+
+	if (recovery_flags & SX_STANDBY_MODE_REQUESTED)
+		flags[cnt++] = CStringGetTextDatum("STANDBY_MODE_REQUESTED");
+
+	Assert(cnt <= MAX_RECOVERY_FLAGS);
+
+	/* Returns bit array as Datum */
+	txt_arr = construct_array_builtin(flags, cnt, TEXTOID);
+	PG_RETURN_ARRAYTYPE_P(txt_arr);
+}