Re: Segmentation fault - PostgreSQL 17.0

Hello.

I am sending you the dump file from command:
      Postgres(at)hdoppxendb1:~$ PGOPTIONS="-c search_path=\"XEN_TS\"" psql -XAt -d "xtimeseries" -c "SELECT encode(get_raw_page('test_idxbrin', 2),'base64')" | base64 -d > dump_block_2.page

The steps for preparing table and index are:

CREATE TABLE test (
      cas int8 NULL
);

CREATE INDEX test_idxbrin ON test USING brin (cas) WITH (pages_per_range='32');

insert into test values (123)

analyse test

vacuum test

CREATE extension pageinspect;

SELECT brin_page_type(get_raw_page('test_idxbrin', 0));

select * from "XEN_TS".brin_metapage_info(get_raw_page('test_idxbrin',0));

select * from brin_revmap_data(get_raw_page('test_idxbrin',1)) limit 1000;

      [cid:8ee2db51-07e6-4d71-a134-5a6a5954a9d7]

select *
from brin_page_items(
get_raw_page('test_idxbrin',2),
'test_idxbrin'
);

Last select returns this error:

SQL Error [57P03]: FATAL: the database system is not yet accepting connections
Detail: Consistent recovery state has not been yet reached.

I am working on getting the backtrace.

Thank You.
 

Best regards, Lubo

________________________________
From: Peter Geoghegan <pg(at)bowt(dot)ie>
Sent: Saturday, 9 November 2024 16:53
To: Tomas Vondra <tomas(at)vondra(dot)me>
Cc: Ľuboslav Špilák <lspilak(at)microstep-hdo(dot)sk>; pgsql-bugs(at)lists(dot)postgresql(dot)org <pgsql-bugs(at)lists(dot)postgresql(dot)org>
Subject: Re: Segmentation fault - PostgreSQL 17.0

On Sat, Nov 9, 2024 at 7:01 AM Tomas Vondra <tomas(at)vondra(dot)me> wrote:
> Considering you're able to trigger the issue easily, it shouldn't be too
> difficult to attach GDB to a backend before running the query.
> Alternatively, you can enable core files, and generate the backtrace
> from that.

This query involves the use of a pageinspect function that accepts a
raw page image. There are some sanity checks of the page, but those
are quite lightweight. It's really not that hard to imagine it
segfaulting from a page image that passes those checks by mistake, but
is nevertheless not a valid BRIN page.

In any case this should be easy to debug: save the page image that the
function segfaults on, verify that it doesn't contain confidential
information, and then post it here. See:

https://wiki.postgresql.org/wiki/Getting_a_stack_trace_of_a_running_PostgreSQL_backend_on_Linux/BSD#contrib.2Fpageinspect_page_dump

--
Peter Geoghegan
________________________________

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