v1-0001-Fix-burst-checkpoint_req-growth.patch

commit 62b447282d7436642984005627f966f93f4a2439
Author: Anton A. Melnikov <a.melnikov@postgrespro.ru>
Date:   Tue Sep 6 12:18:56 2022 +0300

    Remove burst growth of the checkpoint_req on replica.

diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 7a710e6490..0c7510bca5 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -8880,3 +8880,24 @@ SetWalWriterSleeping(bool sleeping)
 	XLogCtl->WalWriterSleeping = sleeping;
 	SpinLockRelease(&XLogCtl->info_lck);
 }
+
+/*
+ * Update the WalWriterSleeping flag.
+ */
+bool IsNewCheckpointWALRecs(void)
+{
+	bool result = false;
+	/*
+		* Get the last safe checkpoint record and check if
+		* there is a new checkpoint WAL records since the
+		* last restartpoint.
+		*/
+	SpinLockAcquire(&XLogCtl->info_lck);
+	if (!XLogRecPtrIsInvalid(XLogCtl->lastCheckPointRecPtr)
+		&& XLogCtl->lastCheckPoint.redo >
+			ControlFile->checkPointCopy.redo)
+				result = true;
+	SpinLockRelease(&XLogCtl->info_lck);
+
+	return result;
+}
diff --git a/src/backend/access/transam/xlogrecovery.c b/src/backend/access/transam/xlogrecovery.c
index ae2af5ae3d..2502e4f726 100644
--- a/src/backend/access/transam/xlogrecovery.c
+++ b/src/backend/access/transam/xlogrecovery.c
@@ -3194,7 +3194,15 @@ XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen,
 			{
 				(void) GetRedoRecPtr();
 				if (XLogCheckpointNeeded(readSegNo))
-					RequestCheckpoint(CHECKPOINT_CAUSE_XLOG);
+				{
+					/*
+						* If there is no new checkpoint WAL records since the
+						* last restartpoint the creation of new one
+						* will certainly fail, so skip it.
+						*/
+					if (IsNewCheckpointWALRecs())
+						RequestCheckpoint(CHECKPOINT_CAUSE_XLOG);
+				}
 			}
 		}
 
diff --git a/src/include/access/xlogrecovery.h b/src/include/access/xlogrecovery.h
index 0aa85d90e8..d1431ab9b0 100644
--- a/src/include/access/xlogrecovery.h
+++ b/src/include/access/xlogrecovery.h
@@ -82,6 +82,7 @@ extern void XLogRecoveryShmemInit(void);
 
 extern void InitWalRecovery(ControlFileData *ControlFile, bool *wasShutdownPtr, bool *haveBackupLabel, bool *haveTblspcMap);
 extern void PerformWalRecovery(void);
+extern bool IsNewCheckpointWALRecs(void);
 
 /*
  * FinishWalRecovery() returns this.  It contains information about the point