From 2b3e4672f7602a6bb46a0735a1b41b635508b290 Mon Sep 17 00:00:00 2001
From: Noah Misch
Date: Mon, 28 Jun 2021 18:34:56 -0700
Subject: Don't ERROR on PreallocXlogFiles() race condition.

Before a restartpoint finishes PreallocXlogFiles(), a startup process
KeepFileRestoredFromArchive() call can unlink the preallocated segment.
If a CHECKPOINT sql command had elicited the restartpoint experiencing
the race condition, that sql command failed.  Moreover, the restartpoint
omitted its log_checkpoints message and some inessential resource
reclamation.  Prevent the ERROR by skipping open() of the segment.
Since these consequences are so minor, no back-patch.

Discussion: https://postgr.es/m/20210202151416.GB3304930@rfd.leadboat.com
---
 src/backend/replication/walreceiver.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

(limited to 'src/backend/replication')

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index eadff8f908f..2be9ad967dc 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -885,8 +885,6 @@ XLogWalRcvWrite(char *buf, Size nbytes, XLogRecPtr recptr)
 
 		if (recvFile < 0 || !XLByteInSeg(recptr, recvSegNo, wal_segment_size))
 		{
-			bool		added;
-
 			/*
 			 * fsync() and close current file before we switch to next one. We
 			 * would otherwise have to reopen this file to fsync it later
@@ -923,7 +921,7 @@ XLogWalRcvWrite(char *buf, Size nbytes, XLogRecPtr recptr)
 
 			/* Create/use new log file */
 			XLByteToSeg(recptr, recvSegNo, wal_segment_size);
-			recvFile = XLogFileInit(recvSegNo, &added);
+			recvFile = XLogFileInit(recvSegNo);
 			recvFileTLI = ThisTimeLineID;
 		}
 
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