From 51f9ea25dc4296948eb851a851bb60e0860c70a1 Mon Sep 17 00:00:00 2001
From: Alvaro Herrera <alvherre@alvh.no-ip.org>
Date: Fri, 14 Nov 2014 15:14:01 -0300
Subject: [PATCH] Allow interrupting GetMultiXactIdMembers
This function has a loop which can lead to uninterruptible process
"stalls" (actually infinite loops) when some bugs are triggered. Avoid
that unpleasant situation by adding a check for interrupts in a place
that shouldn't degrade performance in the normal case.
Backpatch to 9.3. Older branches have an identical loop here, but the
aforementioned bugs are only a problem starting in 9.3 so there doesn't
seem to be any point in backpatching any further.
---
src/backend/access/transam/multixact.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/src/backend/access/transam/multixact.c b/src/backend/access/transam/multixact.c
index bfbe738530e..3c20bb37e4c 100644
--- a/src/backend/access/transam/multixact.c
+++ b/src/backend/access/transam/multixact.c
@@ -1278,6 +1278,7 @@ retry:
{
/* Corner case 2: next multixact is still being filled in */
LWLockRelease(MultiXactOffsetControlLock);
+ CHECK_FOR_INTERRUPTS();
pg_usleep(1000L);
goto retry;
}
--
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