From bcea68c1925a018967e2a8ea42c54552d623234c Mon Sep 17 00:00:00 2001
From: Amul Sul <amul.sul@enterprisedb.com>
Date: Fri, 15 Oct 2021 08:44:09 -0400
Subject: [PATCH] POC rearrange code to remove frequent need of
 LocalSetXLogInsertAllowed()

---
 src/backend/access/transam/xlog.c | 20 ++++++++------------
 1 file changed, 8 insertions(+), 12 deletions(-)

diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 62862255fca..ae561ed7e30 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -8080,7 +8080,6 @@ StartupXLOG(void)
 	 */
 	Insert->fullPageWrites = lastFullPageWrites;
 	UpdateFullPageWrites();
-	LocalXLogInsertAllowed = -1;
 
 	/*
 	 * Emit checkpoint or end-of-recovery record in XLOG, if required.
@@ -8094,17 +8093,18 @@ StartupXLOG(void)
 	if (!XLogRecPtrIsInvalid(XLogCtl->lastReplayedEndRecPtr))
 		promoted = PerformRecoveryXLogAction();
 
-	/* If this is archive recovery, perform post-recovery cleanup actions. */
-	if (ArchiveRecoveryRequested)
-		CleanupAfterArchiveRecovery(EndOfLogTLI, EndOfLog);
-
 	/*
 	 * If any of the critical GUCs have changed, log them before we allow
 	 * backends to write WAL.
 	 */
-	LocalSetXLogInsertAllowed();
 	XLogReportParameters();
 
+	LocalXLogInsertAllowed = -1;
+
+	/* If this is archive recovery, perform post-recovery cleanup actions. */
+	if (ArchiveRecoveryRequested)
+		CleanupAfterArchiveRecovery(EndOfLogTLI, EndOfLog);
+
 	/*
 	 * Local WAL inserts enabled, so it's time to finish initialization of
 	 * commit timestamp.
@@ -9126,7 +9126,7 @@ CreateCheckPoint(int flags)
 	 * enable XLogInsertAllowed.  (This also ensures ThisTimeLineID is
 	 * initialized, which we need here and in AdvanceXLInsertBuffer.)
 	 */
-	if (flags & CHECKPOINT_END_OF_RECOVERY)
+	if ((flags & CHECKPOINT_END_OF_RECOVERY) && IsPostmasterEnvironment)
 		LocalSetXLogInsertAllowed();
 
 	checkPoint.ThisTimeLineID = ThisTimeLineID;
@@ -9304,7 +9304,7 @@ CreateCheckPoint(int flags)
 	 * to just temporarily disable writing until the system has exited
 	 * recovery.
 	 */
-	if (shutdown)
+	if (shutdown && IsPostmasterEnvironment)
 	{
 		if (flags & CHECKPOINT_END_OF_RECOVERY)
 			LocalXLogInsertAllowed = -1;	/* return to "check" state */
@@ -9447,8 +9447,6 @@ CreateEndOfRecoveryRecord(void)
 	xlrec.PrevTimeLineID = XLogCtl->PrevTimeLineID;
 	WALInsertLockRelease();
 
-	LocalSetXLogInsertAllowed();
-
 	START_CRIT_SECTION();
 
 	XLogBeginInsert();
@@ -9469,8 +9467,6 @@ CreateEndOfRecoveryRecord(void)
 	LWLockRelease(ControlFileLock);
 
 	END_CRIT_SECTION();
-
-	LocalXLogInsertAllowed = -1;	/* return to "check" state */
 }
 
 /*
-- 
2.18.0