Re: SIREAD lock versus ACCESS EXCLUSIVE lock

On 04.06.2011 19:19, Tom Lane wrote:
> Heikki Linnakangas<heikki.linnakangas@enterprisedb.com>  writes:
>> On 03.06.2011 21:04, Kevin Grittner wrote:
>>> Also, if anyone has comments or hints about the placement of those
>>> calls, I'd be happy to receive them.
>
>> heap_drop_with_catalog() schedules the relation for deletion at the end
>> of transaction, but it's still possible that the transaction aborts and
>> the heap doesn't get dropped after all. If you put the
>> DropAllPredicateLocksFromTable() call there, and the transaction later
>> aborts, you've lost all the locks already.
>
> But on the third thought: is that wrong?  Surely locks taken by an
> aborted transaction can be discarded.

These are predicate locks - there can be "locks" on the table belonging 
to transactions that have already committed.

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