Re: Postgres Crashing - Mailing list pgsql-general

From Doug Roberts
Subject Re: Postgres Crashing
Date
Msg-id CAOy4PLqyOuk7R9YcKTZhZcdvyaHZRSpfe1W8fOXnP8G2fJh_=Q@mail.gmail.com
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In response to Re: Postgres Crashing  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: Postgres Crashing  (Adrian Klaver <adrian.klaver@aklaver.com>)
List pgsql-general
> So how did containers_reset_recirc() come to clash with
> containers_add_update()? 

They are clashing because another portion of our system is running and updating containers. The reset recirc function was run at the same time to see how our system and the database would handle it. 

The recirc string is formatted like 2000=3,1000=6,5000=0. So the reset recirc function with take a UID (1000 for example) and use that to remove 1000=x from all of the recirc counts for all of the containers that have 1000=x.

We are currently using PG 12.0.

Thanks,

Doug

On Mon, Feb 3, 2020 at 6:21 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
Adrian Klaver <adrian.klaver@aklaver.com> writes:
> Please reply to list also.

> On 2/3/20 2:18 PM, Doug Roberts wrote:
>> Here is what the reset recirc function is doing.
>> ...
>>     UPDATE containers
>> ...

> So how did containers_reset_recirc() come to clash with
> containers_add_update()?

If this is PG 12.0 or 12.1, a likely theory is that this is an
EvalPlanQual bug (which'd be triggered during concurrent updates
of the same row in the table, so that squares with the observation
that locking the table prevents it).  The known bugs in that area
require either before-row-update triggers on the table, or
child tables (either partitioning or traditional inheritance).
So I wonder what the schema of table "containers" looks like.

Or you could have hit some new bug ... but there's not enough
info here to diagnose.

                        regards, tom lane

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