On Wed, 1 Jul 2026 at 07:24, Japin Li <[email protected]> wrote:
>
> Thanks for working on this.

Thank you for testing it!

> While testing the v5 patch, I encountered a lock wait.
>
> 2026-07-01 14:18:43.603 CST [1486593] LOG:  process 1486593 still waiting for 
> AccessExclusiveLock on relation 16384 of database 5 after 1000.106 ms
> 2026-07-01 14:18:43.603 CST [1486593] DETAIL:  Process holding the lock: 
> 1486484. Wait queue: 1486593.
> 2026-07-01 14:18:43.603 CST [1486593] CONTEXT:  waiting for 
> AccessExclusiveLock on relation 16384 of database 5
> 2026-07-01 14:18:43.603 CST [1486593] STATEMENT:  SELECT * FROM gtt_delete;
>
> Is this expected?

Ah yes, you're right. That's not good.

The root cause looks to be the same issue that Pavel reported -- the
ON COMMIT DELETE ROWS does a TRUNCATE when the transaction is
committed, which requires an AccessExclusiveLock. I think the patch
should reduce the lock level required for TRUNCATE on a global
temporary relation to RowExclusiveLock, like DELETE.

I'll try to post an update later this week.

Regards,
Dean


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