From 12e28aac8e8eb76cab13a4e9b696e3dab17f1c99 Mon Sep 17 00:00:00 2001 From: Thomas Munro Date: Tue, 31 May 2022 11:38:19 +1200 Subject: [PATCH] Add debugging help in OwnLatch(). Build farm animal gharial recently failed a few times in a parallel worker's call to OwnLatch() with "ERROR: latch already owned". Let's turn that into a PANIC and show the PID of the owner, to try to learn more. Discussion: https://postgr.es/m/CA%2BhUKGJ_0RGcr7oUNzcHdn7zHqHSB_wLSd3JyS2YC_DYB%2B-V%3Dg%40mail.gmail.com --- src/backend/storage/ipc/latch.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/src/backend/storage/ipc/latch.c b/src/backend/storage/ipc/latch.c index 78c6a892713..41d359d68ed 100644 --- a/src/backend/storage/ipc/latch.c +++ b/src/backend/storage/ipc/latch.c @@ -402,6 +402,8 @@ InitSharedLatch(Latch *latch) void OwnLatch(Latch *latch) { + int owner_pid; + /* Sanity checks */ Assert(latch->is_shared); @@ -410,8 +412,9 @@ OwnLatch(Latch *latch) Assert(selfpipe_readfd >= 0 && selfpipe_owner_pid == MyProcPid); #endif - if (latch->owner_pid != 0) - elog(ERROR, "latch already owned"); + owner_pid = latch->owner_pid; + if (owner_pid != 0) + elog(PANIC, "latch already owned by PID %d", owner_pid); latch->owner_pid = MyProcPid; }