Re: Hot Standby 0.2.1

Simon Riggs wrote:
> On Wed, 2009-09-23 at 19:07 +0300, Heikki Linnakangas wrote:
>
>> Rather than keep the numHeldLocks counters per-proc in proc array, I
>> think it would be simpler to have a single (or one per lock partition)
>> counter in shared memory in lock.c. It's just an optimization to make it
>> faster to find out that there is no loggable AccessExclusiveLocks in the
>> system, so it really rather belongs into the lock manager.
>
> What lock would protect that value? The whole purpose is to avoid taking
> the LockMgrLocks and to give something that is accessible by the locks
> already held by GetRunningTransactionData().

The lock partition lock (so we really need one counter per partition, a
single counter would need additional locking). We're already holding
that in LockAcquire/LockRelease when we need to increment/decrement the
counter.

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