On Thu, May 3, 2012 at 5:18 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> ... btw, it appears to me that the "fast path" patch has broken things
> rather badly in LockReleaseAll. AFAICS it's not honoring either the
> lockmethodid restriction nor the allLocks restriction with respect to
> fastpath locks. Perhaps user locks and session locks are never taken
> fast path, but still it would be better to be making those checks
> further up, no?
User locks are never taken fast path, but session locks can be, so I
think you're right that there is a bug here. I think what we should
probably do is put the nLocks == 0 test before the lockmethodid and
allLocks checks, and then the fast path stuff after those two checks.
In 9.1, we just did this:
if (locallock->proclock == NULL || locallock->lock == NULL) { /*
* We must've run out of shared memory while
trying to set up this * lock. Just forget the local entry. */
Assert(locallock->nLocks == 0); RemoveLocalLock(locallock);
continue; }
...and I just shoved the new logic into that stanza without thinking
hard enough about what order to do things in.
--
Robert Haas
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