Re: Bug in asynchronous Append

Etsuro Fujita писал(а) 2026-07-18 22:59:
> On Sun, Jul 19, 2026 at 4:16 AM Alexander Korotkov
> <aekorotkov(at)gmail(dot)com> wrote:
>> On Sat, Jul 18, 2026 at 10:06 PM Etsuro Fujita
>> <etsuro(dot)fujita(at)gmail(dot)com> wrote:
>> > On Sun, Jul 19, 2026 at 1:00 AM Alexander Korotkov <aekorotkov(at)gmail(dot)com> wrote:
>> > > No worries. Thank you for an update and thank you for your patch.
>> > > I'm going to push (and backpatch to PG 14 where async append was
>> > > introduced) it if no objections.
>> >
>> > Thanks, but this is my fault, so is it possible for me to do so
>> > myself? Anyway, I think the patch will need a bit more work.
>>
>> Sure, please go ahead.
>
> Thanks, will do. I have some other priorities in the coming two
> weeks, so I'm planning to work on the patch a bit more and
> push/backpatch it early next month in time for the August releases.
>
> Best regards,
> Etsuro Fujita

Hi.
I've looked on the suggested patch more attentively in Async Merge
Append thread[1].
There it's a bit more obvious that ExecReScanAppend() behavior in
ExecAppendAsyncProcessPending()
depends on node->as_syncdone. It either sleeps on latch in
ExecAppendAsyncEventWait() or busy loops.
The first behavior seems to be more appropriate, as we still should wait
for all requests
with set callback_pending to complete. Or perhaps, it's not a big
problem, given that this case should
be rare?

1.
https://www.postgresql.org/message-id/flat/59be194c5a409fb9fc9f2031581b8a44%40postgrespro.ru
--
Best regards,
Alexander Pyhalov,
Postgres Professional