From 51742063be4fd8d58fb8571e559fe8ca0abbbb57 Mon Sep 17 00:00:00 2001 From: Alvaro Herrera Date: Sun, 4 Jan 2015 15:48:29 -0300 Subject: Fix thinko in lock mode enum Commit 0e5680f4737a9c6aa94aa9e77543e5de60411322 contained a thinko mixing LOCKMODE with LockTupleMode. This caused misbehavior in the case where a tuple is marked with a multixact with at most a FOR SHARE lock, and another transaction tries to acquire a FOR NO KEY EXCLUSIVE lock; this case should block but doesn't. Include a new isolation tester spec file to explicitely try all the tuple lock combinations; without the fix it shows the problem: starting permutation: s1_begin s1_lcksvpt s1_tuplock2 s2_tuplock3 s1_commit step s1_begin: BEGIN; step s1_lcksvpt: SELECT * FROM multixact_conflict FOR KEY SHARE; SAVEPOINT foo; a 1 step s1_tuplock2: SELECT * FROM multixact_conflict FOR SHARE; a 1 step s2_tuplock3: SELECT * FROM multixact_conflict FOR NO KEY UPDATE; a 1 step s1_commit: COMMIT; With the fixed code, step s2_tuplock3 blocks until session 1 commits, which is the correct behavior. All other cases behave correctly. Backpatch to 9.3, like the commit that introduced the problem. --- src/backend/access/heap/heapam.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'src/backend/access/heap/heapam.c') diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c index f0a5df327d6..fc7472d2650 100644 --- a/src/backend/access/heap/heapam.c +++ b/src/backend/access/heap/heapam.c @@ -6111,6 +6111,7 @@ DoesMultiXactIdConflict(MultiXactId multi, uint16 infomask, int nmembers; MultiXactMember *members; bool result = false; + LOCKMODE wanted = tupleLockExtraInfo[lockmode].hwlock; allow_old = !(infomask & HEAP_LOCK_MASK) && HEAP_XMAX_IS_LOCKED_ONLY(infomask); nmembers = GetMultiXactIdMembers(multi, &members, allow_old); @@ -6121,11 +6122,12 @@ DoesMultiXactIdConflict(MultiXactId multi, uint16 infomask, for (i = 0; i < nmembers; i++) { TransactionId memxid; - LockTupleMode memlockmode; + LOCKMODE memlockmode; memlockmode = LOCKMODE_from_mxstatus(members[i].status); + /* ignore members that don't conflict with the lock we want */ - if (!DoLockModesConflict(memlockmode, lockmode)) + if (!DoLockModesConflict(memlockmode, wanted)) continue; /* ignore members from current xact */ -- cgit v1.2.3