From 946647f845d0b0762656a8e07055f501c4b29688 Mon Sep 17 00:00:00 2001 From: Fujii Masao Date: Fri, 6 Sep 2019 14:27:25 +0900 Subject: [PATCH] Make pg_promote() detect postmaster death while waiting for promotion to end. Previously even if postmaster died and WaitLatch() woke up with that event while pg_promote() was waiting for the standby promotion to finish, pg_promote() did nothing special and kept waiting until timeout occurred. This could cause a busy loop. This patch make pg_promote() return false immediately when postmaster dies, to avoid such a busy loop. Back-patch to v12 where pg_promote() was added. Author: Fujii Masao Reviewed-by: Michael Paquier Discussion: https://postgr.es/m/CAHGQGwEs9ROgSp+QF+YdDU+xP8W=CY1k-_Ov-d_Z3JY+to3eXA@mail.gmail.com --- src/backend/access/transam/xlogfuncs.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-) diff --git a/src/backend/access/transam/xlogfuncs.c b/src/backend/access/transam/xlogfuncs.c index 4795c6fa94..8a70503228 100644 --- a/src/backend/access/transam/xlogfuncs.c +++ b/src/backend/access/transam/xlogfuncs.c @@ -759,6 +759,8 @@ pg_promote(PG_FUNCTION_ARGS) #define WAITS_PER_SECOND 10 for (i = 0; i < WAITS_PER_SECOND * wait_seconds; i++) { + int rc; + ResetLatch(MyLatch); if (!RecoveryInProgress()) @@ -766,10 +768,17 @@ pg_promote(PG_FUNCTION_ARGS) CHECK_FOR_INTERRUPTS(); - (void) WaitLatch(MyLatch, - WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH, - 1000L / WAITS_PER_SECOND, - WAIT_EVENT_PROMOTE); + rc = WaitLatch(MyLatch, + WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH, + 1000L / WAITS_PER_SECOND, + WAIT_EVENT_PROMOTE); + + /* + * Emergency bailout if postmaster has died. This is to avoid the + * necessity for manual cleanup of all postmaster children. + */ + if (rc & WL_POSTMASTER_DEATH) + PG_RETURN_BOOL(false); } ereport(WARNING,