Hi!
Platform: PostgreSQL 7.1.3, Linux 2.4.8, egcs 2.91.66
PostgreSQL forgets to release lock until shutdown in this scenario:
CREATE TABLE dummy (X integer);
session1 session2
------------------------------------------------------------
BEGIN; |
|BEGIN;
SELECT * FROM dummy; |
|SELECT * FROM dummy;
LOCK TABLE dummy; |
|LOCK TABLE dummy;
deadlock....
\q \q
Deadlock is OK here, but I can't access dummy table until I restart postmaster
Everything's fine, when I comment out * marked lines in
backend/storage/lmgr/proc.c:
if (myHeldLocks != 0)
{
int aheadRequests = 0;
proc = (PROC *) MAKE_PTR(waitQueue->links.next);
for (i = 0; i < waitQueue->size; i++)
{
/* Must he wait for me? */
if (lockctl->conflictTab[proc->waitLockMode] & myHeldLocks)
{
/* Must I wait for him ? */
* if (lockctl->conflictTab[lockmode] & proc->heldLocks)
* {
* /* Yes, can report deadlock failure immediately */
* MyProc->errType = STATUS_ERROR;
* return STATUS_ERROR;
* }
Then the standard deadlock detection procedure is used.
greetings,
tom
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