Re: Crash related to Shared Memory

On 2/16/26 09:42, Reshmithaa wrote:
> Hi Tomas Vondra,
>
>> What extensions are you using? Especially extensions third-party
>
>> extensions?
>
> We are working on our own columnar extension and have modified the
> PostgreSQL source code to enable pg stats for foreign tables and to
> support autoanalyze and autovacuum on foreign tables.
>

Then it matches the explanation in Robert's commit message. Chances are
that commit will solve the crash, but the other errors in your traces
are likely to remain.

> From PostgreSQL 15 onward, statistics were moved to shared memory. We
> started observing this issue in production after upgrading from
> PostgreSQL 14 to PostgreSQL 17.2 / 17.7.
>
> Could this dsa issue be related to pg stats?
>

You literally have the traces full of error messages like this:

[568804]:ERROR: 53200: out of memory
[568804]:DETAIL: Failed while allocating entry 2/17266/55068384.
[568804]:LOCATION: pgstat_get_entry_ref, pgstat_shmem.c:510
[568804]:STATEMENT: ANALYZE tab2_temp

That's clearly related to pgstat. My bet is that's a bug in your
extension, not sure where.

>
>> The second trace
>
>> unfortunately does not show what happened to PID 2037344 before it
>
>> crashes, which would be very interesting to know. Was it an OOM too?
>
> The process with PID 2037344 did not terminate due to an OOM intead
> ended with segfalut.
>

The question is what happened to the process before it segfaults.

cheers
--
Tomas Vondra