From: Jehan-Guillaume de Rorthais <jgdr@dalibo.com>
Date: Fri, 31 Jul 2020 10:58:40 +0200
Subject: [PATCH 1/4] demote: setter functions for LocalXLogInsert local
 variable

Adds functions extern LocalSetXLogInsertNotAllowed() and
LocalSetXLogInsertCheckRecovery() to set the local variable
LocalXLogInsert respectively to 0 and -1.

These functions are declared as extern for future need in
the demote patch.

Function LocalSetXLogInsertAllowed() already exists and
declared as static as it is not needed outside of xlog.h.
---
 src/backend/access/transam/xlog.c | 27 +++++++++++++++++++++++----
 src/include/access/xlog.h         |  2 ++
 2 files changed, 25 insertions(+), 4 deletions(-)

diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 09c01ed4ae..c0d79f192c 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -7711,7 +7711,7 @@ StartupXLOG(void)
 	Insert->fullPageWrites = lastFullPageWrites;
 	LocalSetXLogInsertAllowed();
 	UpdateFullPageWrites();
-	LocalXLogInsertAllowed = -1;
+	LocalSetXLogInsertCheckRecovery();
 
 	if (InRecovery)
 	{
@@ -8219,6 +8219,25 @@ LocalSetXLogInsertAllowed(void)
 	InitXLOGAccess();
 }
 
+/*
+ * Make XLogInsertAllowed() return false in the current process only.
+ */
+void
+LocalSetXLogInsertNotAllowed(void)
+{
+	LocalXLogInsertAllowed = 0;
+}
+
+/*
+ * Make XLogInsertCheckRecovery() return false in the current process only.
+ */
+void
+LocalSetXLogInsertCheckRecovery(void)
+{
+	LocalXLogInsertAllowed = -1;
+}
+
+
 /*
  * Subroutine to try to fetch and validate a prior checkpoint record.
  *
@@ -9004,9 +9023,9 @@ CreateCheckPoint(int flags)
 	if (shutdown)
 	{
 		if (flags & CHECKPOINT_END_OF_RECOVERY)
-			LocalXLogInsertAllowed = -1;	/* return to "check" state */
+			LocalSetXLogInsertCheckRecovery(); /* return to "check" state */
 		else
-			LocalXLogInsertAllowed = 0; /* never again write WAL */
+			LocalSetXLogInsertNotAllowed(); /* never again write WAL */
 	}
 
 	/*
@@ -9159,7 +9178,7 @@ CreateEndOfRecoveryRecord(void)
 
 	END_CRIT_SECTION();
 
-	LocalXLogInsertAllowed = -1;	/* return to "check" state */
+	LocalSetXLogInsertCheckRecovery();	/* return to "check" state */
 }
 
 /*
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 221af87e71..8c9cadc6da 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -306,6 +306,8 @@ extern RecoveryState GetRecoveryState(void);
 extern bool HotStandbyActive(void);
 extern bool HotStandbyActiveInReplay(void);
 extern bool XLogInsertAllowed(void);
+extern void LocalSetXLogInsertNotAllowed(void);
+extern void LocalSetXLogInsertCheckRecovery(void);
 extern void GetXLogReceiptTime(TimestampTz *rtime, bool *fromStream);
 extern XLogRecPtr GetXLogReplayRecPtr(TimeLineID *replayTLI);
 extern XLogRecPtr GetXLogInsertRecPtr(void);
-- 
2.20.1


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