Horton

Re: Large expressions in indexes can't be stored (non-TOASTable)

Nathan Bossart <nathandbossart@gmail.com>

View thread View on postgr.es
From: Nathan Bossart <nathandbossart@gmail.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Nisha Moond <nisha.moond412@gmail.com>, Euler Taveira <euler@eulerto.com>, Michael Paquier <michael@paquier.xyz>, Amit Kapila <amit.kapila16@gmail.com>, Alexander Lakhin <exclusion@gmail.com>, "Jonathan S. Katz" <jkatz@postgresql.org>, tomas@vondra.me, "hlinnaka@iki.fi PostgreSQL Hackers" <pgsql-hackers@lists.postgresql.org>
Date: 2025-04-29T18:09:32Z
Lists: pgsql-hackers 
On Tue, Apr 29, 2025 at 02:01:54PM -0400, Tom Lane wrote:
> Nathan Bossart <nathandbossart@gmail.com> writes:
>> Thanks.  I'll stash this away for July unless someone wants to argue that
>> it's fair game for v18.  IMHO this isn't nearly urgent enough for that, and
>> the bugs will continue to exist on older major versions regardless.
> 
> I'm inclined to argue that it's a bug fix and therefore still in-scope
> for v18.  The fact that we can't back-patch such a change is all the
> more reason to not let it slide another year.  But probably the RMT
> should make the call.

Tomas, Heikki: Thoughts on removing pg_replication_origin's TOAST table
post-feature-freeze?  The proposed commit message explains what's going on:

	A few places that access this catalog do not set up an active
	snapshot before potentially accessing its TOAST table, which is
	unsafe.  However, roname (the replication origin name) is the only
	varlena column, so this is only ever a problem if the name requires
	out-of-line storage, which seems unlikely.  This commit removes its
	TOAST table to avoid needing to set up a snapshot, and it
	establishes a length restriction of 512 bytes for replication
	origin names.  Even without this restriction, names that would
	require out-of-line storage would fail with a "row is too big"
	error; the additional length restriction just provides a more
	specific error message.

-- 
nathan

Commits

  1. Ensure we have a snapshot when updating various system catalogs.

  2. Remove pg_replication_origin's TOAST table.

  3. Restrict password hash length.

  4. Ensure we have a snapshot when updating pg_index entries.

  5. Add TOAST table to pg_index.

  6. Add toast tables to most system catalogs