v1-0001-Fix-WaitLSNWakeup-fast-path-check-for-InvalidXLog.patch
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Filename: v1-0001-Fix-WaitLSNWakeup-fast-path-check-for-InvalidXLog.patch
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Format: format-patch
Series: patch v1-0001
Subject: Fix WaitLSNWakeup() fast-path check for InvalidXLogRecPtr
| File | + | − |
|---|---|---|
| src/backend/access/transam/xlogwait.c | 6 | 2 |
From de673ec025074cd95ad4a4e53e2c26fcc14d5a4a Mon Sep 17 00:00:00 2001 From: alterego655 <824662526@qq.com> Date: Fri, 14 Nov 2025 09:34:03 +0800 Subject: [PATCH v1] Fix WaitLSNWakeup() fast-path check for InvalidXLogRecPtr WaitLSNWakeup() incorrectly returned early when called with InvalidXLogRecPtr (meaning "wake all waiters"), because the fast-path check compared minWaitedLSN > 0 without validating currentLSN first. This caused WAIT FOR LSN commands to wait indefinitely during standby promotion until random signals woke them. Add XLogRecPtrIsValid() check before the comparison so InvalidXLogRecPtr bypasses the fast-path and wakes all waiters immediately. --- src/backend/access/transam/xlogwait.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/src/backend/access/transam/xlogwait.c b/src/backend/access/transam/xlogwait.c index 34fa41ed9b2..78de93db47f 100644 --- a/src/backend/access/transam/xlogwait.c +++ b/src/backend/access/transam/xlogwait.c @@ -270,8 +270,12 @@ WaitLSNWakeup(WaitLSNType lsnType, XLogRecPtr currentLSN) Assert(i >= 0 && i < (int) WAIT_LSN_TYPE_COUNT); - /* Fast path check */ - if (pg_atomic_read_u64(&waitLSNState->minWaitedLSN[i]) > currentLSN) + /* + * Fast path check. Skip if currentLSN is InvalidXLogRecPtr, which means + * "wake all waiters" (e.g., during promotion when recovery ends). + */ + if (XLogRecPtrIsValid(currentLSN) && + pg_atomic_read_u64(&waitLSNState->minWaitedLSN[i]) > currentLSN) return; wakeupWaiters(lsnType, currentLSN); -- 2.51.0