From: | Pavel Borisov <pashkin(dot)elfe(at)gmail(dot)com> |
---|---|
To: | Greg Nancarrow <gregn4422(at)gmail(dot)com> |
Cc: | Michael Paquier <michael(at)paquier(dot)xyz>, Pengchengliu <pengchengliu(at)tju(dot)edu(dot)cn>, Andres Freund <andres(at)anarazel(dot)de>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: Re: Parallel scan with SubTransGetTopmostTransaction assert coredump |
Date: | 2021-05-24 13:55:51 |
Message-ID: | CALT9ZEG4vzW1C=U4-AvgCA9=QEqVfrxaQ8PQ98CGNZ5LBG96kQ@mail.gmail.com |
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Thread: | |
Lists: | pgsql-hackers |
пн, 24 мая 2021 г. в 09:22, Greg Nancarrow <gregn4422(at)gmail(dot)com>:
> On Mon, May 24, 2021 at 2:50 PM Michael Paquier <michael(at)paquier(dot)xyz>
> wrote:
> >
> > On Mon, May 24, 2021 at 12:04:37PM +1000, Greg Nancarrow wrote:
> > > Keep cfbot happy, use the PG14 patch as latest.
> >
> > This stuff is usually very tricky.
>
> Agreed. That's why I was looking for experts in this snapshot-handling
> code, to look closer at this issue, check my proposed fix, come up
> with a better solution etc.
>
> >Do we have a way to reliably
> > reproduce the report discussed here?
>
Using a recipe similar to what has been described above in the thread, I
reliably reproduced the bug in many Postgres versions. (v.11, v.13 etc.).
1. Make & make install
2. Make check
3. run SubTransGetTopmostTransaction-rep.sh in the Postgres source code
dir.
The test fails with coredumps in around 10 minutes. With applied fix has
never failed yet.
(Though transaction snapshots kitchen is indeed tricky and I am not 100%
sure the fix does right thing which is safe in all circumstances)
Attachment | Content-Type | Size |
---|---|---|
SubTransGetTopmostTransaction-rep.sh | text/x-sh | 840 bytes |
init_test.sql | application/octet-stream | 681 bytes |
sub_120.sql | application/octet-stream | 18.5 KB |
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