From 8c7a74c3239ce29940582643533a190721b395c0 Mon Sep 17 00:00:00 2001 From: Alexander Korotkov Date: Sat, 12 Sep 2026 23:30:03 +0300 Subject: [PATCH] Re-read standby LSN after recovery ends WaitForLSN() samples the current position before checking whether recovery is still in progress. If recovery reaches the target and ends between those operations, the promotion path can compare against the stale sample and incorrectly return NOT_IN_RECOVERY. Read the position again after observing that recovery has ended, before deciding whether promotion reached the target. Author: Xuneng Zhou Discussion: https://postgr.es/m/CABPTF7U0gW5%2B-4oL7-qdML-yerZxUb7ku4QXp7JxCYo0qyJ_Tw%40mail.gmail.com Reviewed-by: Alexander Korotkov Backpatch-through: 19 --- src/backend/access/transam/xlogwait.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/src/backend/access/transam/xlogwait.c b/src/backend/access/transam/xlogwait.c index c624f9163a1..4fd11e66284 100644 --- a/src/backend/access/transam/xlogwait.c +++ b/src/backend/access/transam/xlogwait.c @@ -488,11 +488,19 @@ WaitForLSN(WaitLSNType lsnType, XLogRecPtr targetLSN, int64 timeout) if (WaitLSNTypeRequiresRecovery(lsnType) && !RecoveryInProgress()) { /* - * Recovery was ended, but check if target LSN was already + * Recovery has ended, but check if target LSN was already * reached. */ deleteLSNWaiter(lsnType); + /* + * Recovery may have advanced the current position after + * currentLSN was read above. Once RecoveryInProgress() returns + * false, the final position is stable, so read it again before + * deciding whether promotion reached the target. + */ + currentLSN = GetCurrentLSNForWaitType(lsnType); + if (PromoteIsTriggered() && targetLSN <= currentLSN) return WAIT_LSN_RESULT_SUCCESS; return WAIT_LSN_RESULT_NOT_IN_RECOVERY;