Re: REPACK (ANALYZE) within transaction block segfaults

Nathan Bossart <nathandbossart(at)gmail(dot)com> wrote:

> On Fri, Aug 28, 2026 at 01:09:59AM +0900, Fujii Masao wrote:
> > On Thu, Aug 27, 2026 at 10:56 PM Nathan Bossart
> > <nathandbossart(at)gmail(dot)com> wrote:
> >> Presumably we need to handle transaction blocks a bit like how vacuum()
> >> does. Or maybe even prevent REPACK (ANALYZE) within a transaction block.
> >
> > I looked into this a bit. I think the problem is not ordinary
> > transaction blocks themselves, but non-top-level execution, such as the
> > DO block in the reproducer.
> >
> > So the attached patch rejects only non-top-level REPACK (ANALYZE)
> > commands.
>
> Hm. Couldn't we do something like the in_outer_xact/use_own_xacts stuff in
> vacuum() to get it working instead?

I think there are just two different concepts (for historical reasons?):
vacuum_rel() expects no active transaction on entry, while cluster_rel()
handles transaction boundaries on its own.

Since REPACK (ANALYZE) is effectively VACUUM (FULL, ANALYZE), I'd prefer the
same behavior, i.e. prohibiting execution both in a transaction block and in a
function:

postgres=# BEGIN; VACUUM (FULL, ANALYZE) t; END;
BEGIN
ERROR: VACUUM cannot run inside a transaction block
ROLLBACK

postgres=# DO $$ BEGIN EXECUTE 'VACUUM (FULL, ANALYZE) t'; END $$;
ERROR: VACUUM cannot be executed from a function or procedure
CONTEXT: SQL statement "VACUUM (FULL, ANALYZE) t"
PL/pgSQL function inline_code_block line 1 at EXECUTE

postgres=# BEGIN; REPACK (ANALYZE) t; END;
BEGIN
ERROR: REPACK (ANALYZE) cannot run inside a transaction block
ROLLBACK

postgres=# DO $$ BEGIN EXECUTE 'REPACK (ANALYZE) t'; END $$;
ERROR: REPACK (ANALYZE) cannot be executed from a function or procedure
CONTEXT: SQL statement "REPACK (ANALYZE) t"
PL/pgSQL function inline_code_block line 1 at EXECUTE

The attached patch does that.

--
Antonin Houska
Web: https://www.cybertec-postgresql.com