Re: ERROR: too many dynamic shared memory segments - Mailing list pgsql-general

From Nicola Contu
Subject Re: ERROR: too many dynamic shared memory segments
Date
Msg-id CAMTZZh2ffaJG9FPqwm2MLysHDekiXXDwOhXdSVppxwzYg7ReXA@mail.gmail.com
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In response to Re: ERROR: too many dynamic shared memory segments  (Thomas Munro <thomas.munro@gmail.com>)
Responses Re: ERROR: too many dynamic shared memory segments
List pgsql-general
Hi Thomas,
unfortunately I can't find any core dump to help you more.
Thanks for the fix, we are in the process of installing 12.1 in production, so we can still wait on this release and go live with 12.2

I will let you know at this point if I still get this after installing 12.2 trying to build a core dump file.

Do you still recommend to increase max_conn?


Il giorno gio 30 gen 2020 alle ore 23:41 Thomas Munro <thomas.munro@gmail.com> ha scritto:
On Wed, Jan 29, 2020 at 11:53 PM Thomas Munro <thomas.munro@gmail.com> wrote:
> On Wed, Jan 29, 2020 at 10:37 PM Nicola Contu <nicola.contu@gmail.com> wrote:
> > This is the error on postgres log of the segmentation fault :
> >
> > 2020-01-21 14:20:29 GMT [] [42222]: [108-1] db=,user= LOG:  server process (PID 2042) was terminated by signal 11: Segmentation fault
> > 2020-01-21 14:20:29 GMT [] [42222]: [109-1] db=,user= DETAIL:  Failed process was running: select pid from pg_stat_activity where query ilike 'REFRESH MATERIALIZED VIEW CONCURRENTLY matview_vrs_request_stats'
> > 2020-01-21 14:20:29 GMT [] [42222]: [110-1] db=,user= LOG:  terminating any other active server processes

> That gave me an idea...  I hacked my copy of PostgreSQL to flip a coin
> to decide whether to pretend there are no slots free (see below), and
> I managed to make it crash in the regression tests when doing a
> parallel index build.  It's late here now, but I'll look into that
> tomorrow.  It's possible that the parallel index code needs to learn
> to cope with that.

Hi Nicola,

Without more information I can't know if I found the same bug you
experienced, but I think it's likely.  I have committed a fix for
that, which will be available in the next release (mid-February).

https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=74618e77b43cfce670b4725d5b9a300a2afd12d1

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