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* BUG #17591: elog(ERROR) cause SharedSnapshotLock deadlock
@ 2022-08-22 06:23 PG Bug reporting form <noreply@postgresql.org>
0 siblings, 2 replies; 3+ messages in thread
From: PG Bug reporting form @ 2022-08-22 06:23 UTC (permalink / raw)
To: pgsql-bugs@lists.postgresql.org; +Cc: ma100@hotmail.com
The following bug has been logged on the website:
Bug reference: 17591
Logged by: ma liangzhu
Email address: ma100@hotmail.com
PostgreSQL version: 14.5
Operating system: centos7
Description:
in lock.c, we can see code Release lock before return , e.g.
```c
996: LockAcquireExtended
{
LWLockAcquire(partitionLock, LW_EXCLUSIVE);
proclock = SetupLockInTable( );
if (!proclock)
{
LWLockRelease(partitionLock); --- Release lock before return
ereport(ERROR,)
}
}
```
bug we can see some code doesn't release the lock. Does it may cause
deadlock?
```c
LockRelease()
{
LWLockAcquire(partitionLock, LW_EXCLUSIVE);
lock = locallock->lock;
if (!lock)
{
lock = (LOCK *) hash_search_with_hash_value( );
if (!lock)
2126: elog(ERROR, "failed to re-find shared lock object"); -- exit
without release
}
```
^ permalink raw reply [nested|flat] 3+ messages in thread
* Re: BUG #17591: elog(ERROR) cause SharedSnapshotLock deadlock
@ 2022-08-22 07:45 Zhang Mingli <zmlpostgres@gmail.com>
parent: PG Bug reporting form <noreply@postgresql.org>
1 sibling, 0 replies; 3+ messages in thread
From: Zhang Mingli @ 2022-08-22 07:45 UTC (permalink / raw)
To: ma100@hotmail.com; pgsql-bugs@lists.postgresql.org
Hi,
Didn’t see any bugs here, it report an error and the transaction will end and release all resources.
Regards,
Zhang Mingli
On Aug 22, 2022, 14:58 +0800, PG Bug reporting form <noreply@postgresql.org>, wrote:
> The following bug has been logged on the website:
>
> Bug reference: 17591
> Logged by: ma liangzhu
> Email address: ma100@hotmail.com
> PostgreSQL version: 14.5
> Operating system: centos7
> Description:
>
> in lock.c, we can see code Release lock before return , e.g.
>
> ```c
> 996: LockAcquireExtended
> {
> LWLockAcquire(partitionLock, LW_EXCLUSIVE);
>
> proclock = SetupLockInTable( );
> if (!proclock)
> {
> LWLockRelease(partitionLock); --- Release lock before return
> ereport(ERROR,)
> }
> }
> ```
>
> bug we can see some code doesn't release the lock. Does it may cause
> deadlock?
>
> ```c
> LockRelease()
> {
> LWLockAcquire(partitionLock, LW_EXCLUSIVE);
>
> lock = locallock->lock;
> if (!lock)
> {
> lock = (LOCK *) hash_search_with_hash_value( );
> if (!lock)
> 2126: elog(ERROR, "failed to re-find shared lock object"); -- exit
> without release
> }
> ```
>
^ permalink raw reply [nested|flat] 3+ messages in thread
* Re: BUG #17591: elog(ERROR) cause SharedSnapshotLock deadlock
@ 2022-08-22 13:13 Tom Lane <tgl@sss.pgh.pa.us>
parent: PG Bug reporting form <noreply@postgresql.org>
1 sibling, 0 replies; 3+ messages in thread
From: Tom Lane @ 2022-08-22 13:13 UTC (permalink / raw)
To: ma100@hotmail.com; +Cc: pgsql-bugs@lists.postgresql.org
PG Bug reporting form <noreply@postgresql.org> writes:
> in lock.c, we can see code Release lock before return , e.g.
> ...
> bug we can see some code doesn't release the lock. Does it may cause
> deadlock?
Transaction cleanup will automatically release all locks (and other
resources too). So the places that do a manual release before
elog(ERROR) are something of a waste of code space. It might be worth
doing that if you're concerned about holding the lock for the minimum
possible amount of time; but usually that's only a consideration for
very heavily-contended spinlocks or LWLocks.
regards, tom lane
^ permalink raw reply [nested|flat] 3+ messages in thread
end of thread, other threads:[~2022-08-22 13:13 UTC | newest]
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2022-08-22 06:23 BUG #17591: elog(ERROR) cause SharedSnapshotLock deadlock PG Bug reporting form <noreply@postgresql.org>
2022-08-22 07:45 ` Zhang Mingli <zmlpostgres@gmail.com>
2022-08-22 13:13 ` Tom Lane <tgl@sss.pgh.pa.us>
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