| From: | Thomas Munro <thomas(dot)munro(at)gmail(dot)com> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | Bharath Rupireddy <bharath(dot)rupireddyforpostgres(at)gmail(dot)com>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>, Arseny Sher <a(dot)sher(at)postgrespro(dot)ru> |
| Subject: | Re: Parallel query hangs after a smart shutdown is issued |
| Date: | 2020-08-14 06:03:47 |
| Message-ID: | CA+hUKGK-1GafK3UE2gARcotsjEdTExznxi1SgnnYJfKAiR_Pcw@mail.gmail.com |
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| Lists: | pgsql-hackers |
On Fri, Aug 14, 2020 at 4:45 AM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> I wrote:
> > Hmmm ... maybe that should be more like
> > if (smartShutState != SMART_NORMAL_USAGE &&
> > backend_type == BACKEND_TYPE_NORMAL)
>
> After some more rethinking and testing, here's a v5 that feels
> fairly final to me. I realized that the logic in canAcceptConnections
> was kind of backwards: it's better to check the main pmState restrictions
> first and then the smart-shutdown restrictions afterwards.
LGTM. I tested this a bit today and it did what I expected for
parallel queries and vacuum, on primary and standby.
> I'm assuming we want to back-patch this as far as 9.6, where parallel
> query began to be a thing.
Yeah. I mean, it's more radical than what I thought we'd be doing for
this, but you could get into real trouble by running in smart shutdown
mode without the autovac infrastructure alive.
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