Re: Revert: Remove useless self-joins *and* -DREALLOCATE_BITMAPSETS make server crash, regress test fail.

David Rowley <dgrowleyml@gmail.com>

From: David Rowley <dgrowleyml@gmail.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Andrew Dunstan <andrew@dunslane.net>, Richard Guo <guofenglinux@gmail.com>, jian he <jian.universality@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2024-05-07T22:37:26Z
Lists: pgsql-hackers
On Wed, 8 May 2024 at 10:35, David Rowley <dgrowleyml@gmail.com> wrote:
>
> On Wed, 8 May 2024 at 06:20, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> > I find that Richard's proposed fix makes the core regression tests
> > pass, but we still fail check-world.  So I'm afraid we need something
> > more aggressive, like the attached which makes make_restrictinfo
> > copy all its input bitmapsets.  Without that, we still have sharing
> > of bitmapsets across different RestrictInfos, which seems pretty
> > scary given what we now see about the effects of 00b41463c.  This
> > seems annoyingly expensive, but maybe there's little choice?
>
> We could make the policy copy-on-modify.  If you put bms_copy around
> the bms_del_member() calls in remove_rel_from_query(), does it pass
> then?

err, I mean bms_copy() the set before passing to bms_del_member().

David



Commits

  1. Make left-join removal safe under -DREALLOCATE_BITMAPSETS.

  2. Revert: Remove useless self-joins

  3. Remove mention of nchar