0009-xlog.c-Make-xlog_redo-not-depend-on-ThisTimeLineID-g.patch

From 17d9c1e75fb233ba64b135696f005a85d04ca814 Mon Sep 17 00:00:00 2001
From: Robert Haas <rhaas@postgresql.org>
Date: Mon, 1 Nov 2021 12:58:15 -0400
Subject: [PATCH 09/11] xlog.c: Make xlog_redo() not depend on ThisTimeLineID
 global variable.

The same value is available in shared memory as XLogCtl->replayEndTLI
so use that instead.
---
 src/backend/access/transam/xlog.c | 20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)

diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 054241403c..b6f30382eb 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -10349,6 +10349,10 @@ xlog_redo(XLogReaderState *record)
 {
 	uint8		info = XLogRecGetInfo(record) & ~XLR_INFO_MASK;
 	XLogRecPtr	lsn = record->EndRecPtr;
+	TimeLineID	replayTLI;
+
+	/* No other process can change this, so we can read it without a lock. */
+	replayTLI = XLogCtl->replayEndTLI;
 
 	/*
 	 * In XLOG rmgr, backup blocks are only used by XLOG_FPI and
@@ -10462,10 +10466,10 @@ xlog_redo(XLogReaderState *record)
 		 * We should've already switched to the new TLI before replaying this
 		 * record.
 		 */
-		if (checkPoint.ThisTimeLineID != ThisTimeLineID)
+		if (checkPoint.ThisTimeLineID != replayTLI)
 			ereport(PANIC,
 					(errmsg("unexpected timeline ID %u (should be %u) in checkpoint record",
-							checkPoint.ThisTimeLineID, ThisTimeLineID)));
+							checkPoint.ThisTimeLineID, replayTLI)));
 
 		RecoveryRestartPoint(&checkPoint);
 	}
@@ -10518,10 +10522,10 @@ xlog_redo(XLogReaderState *record)
 		SpinLockRelease(&XLogCtl->info_lck);
 
 		/* TLI should not change in an on-line checkpoint */
-		if (checkPoint.ThisTimeLineID != ThisTimeLineID)
+		if (checkPoint.ThisTimeLineID != replayTLI)
 			ereport(PANIC,
 					(errmsg("unexpected timeline ID %u (should be %u) in checkpoint record",
-							checkPoint.ThisTimeLineID, ThisTimeLineID)));
+							checkPoint.ThisTimeLineID, replayTLI)));
 
 		RecoveryRestartPoint(&checkPoint);
 	}
@@ -10548,10 +10552,10 @@ xlog_redo(XLogReaderState *record)
 		 * We should've already switched to the new TLI before replaying this
 		 * record.
 		 */
-		if (xlrec.ThisTimeLineID != ThisTimeLineID)
+		if (xlrec.ThisTimeLineID != replayTLI)
 			ereport(PANIC,
 					(errmsg("unexpected timeline ID %u (should be %u) in checkpoint record",
-							xlrec.ThisTimeLineID, ThisTimeLineID)));
+							xlrec.ThisTimeLineID, replayTLI)));
 	}
 	else if (info == XLOG_NOOP)
 	{
@@ -10621,7 +10625,7 @@ xlog_redo(XLogReaderState *record)
 			if (ControlFile->minRecoveryPoint < lsn)
 			{
 				ControlFile->minRecoveryPoint = lsn;
-				ControlFile->minRecoveryPointTLI = ThisTimeLineID;
+				ControlFile->minRecoveryPointTLI = replayTLI;
 			}
 			ControlFile->backupStartPoint = InvalidXLogRecPtr;
 			ControlFile->backupEndRequired = false;
@@ -10662,7 +10666,7 @@ xlog_redo(XLogReaderState *record)
 		if (minRecoveryPoint != InvalidXLogRecPtr && minRecoveryPoint < lsn)
 		{
 			ControlFile->minRecoveryPoint = lsn;
-			ControlFile->minRecoveryPointTLI = ThisTimeLineID;
+			ControlFile->minRecoveryPointTLI = replayTLI;
 		}
 
 		CommitTsParameterChange(xlrec.track_commit_timestamp,
-- 
2.24.3 (Apple Git-128)