Re: SIREAD lock versus ACCESS EXCLUSIVE lock

Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>

From: Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>
To: Kevin Grittner <Kevin.Grittner@wicourts.gov>
Cc: "<Simon Riggs" <simon@2ndquadrant.com>, Dan Ports <drkp@csail.mit.edu>, pgsql-hackers@postgresql.org
Date: 2011-06-03T20:50:40Z
Lists: pgsql-hackers
On 03.06.2011 23:44, Kevin Grittner wrote:
> Heikki Linnakangas<heikki.linnakangas@enterprisedb.com>  wrote:
>
>> I think you'll need to just memorize the lock deletion command in
>> a backend-local list, and perform the deletion in a post-commit
>> function.
>
> Hmm.  As mentioned earlier in the thread, cleaning these up doesn't
> actually have any benefit beyond freeing space in the predicate
> locking collections.  I'm not sure that benefit is enough to justify
> this much new mechanism.  Maybe I should just leave them alone and
> let them get cleaned up in due course with the rest of the locks.
> Any opinions on that?

Is there a chance of false positives if oid wraparound happens and a new 
table gets the same oid as the old one? It's also possible for a heap to 
get the OID of an old index or vice versa, will that confuse things?

-- 
   Heikki Linnakangas
   EnterpriseDB   http://www.enterprisedb.com