Re: Incorrect result of bitmap heap scan.

vignesh C <vignesh21@gmail.com>

From: vignesh C <vignesh21@gmail.com>
To: Matthias van de Meent <boekewurm+postgres@gmail.com>
Cc: Peter Geoghegan <pg@bowt.ie>, Tom Lane <tgl@sss.pgh.pa.us>, Andres Freund <andres@anarazel.de>, Andrew Dunstan <andrew@dunslane.net>, Melanie Plageman <melanieplageman@gmail.com>, Thomas Munro <thomas.munro@gmail.com>, Konstantin Knizhnik <knizhnik@garret.ru>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>, Alexander Kuzmenkov <akuzmenkov@timescale.com>
Date: 2025-03-16T12:55:32Z
Lists: pgsql-hackers
On Wed, 5 Mar 2025 at 16:43, Matthias van de Meent
<boekewurm+postgres@gmail.com> wrote:
>
> On Sun, 2 Mar 2025 at 01:35, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> >
> > Peter Geoghegan <pg@bowt.ie> writes:
> > > Is everybody in agreement about committing and back patching this fix,
> > > which simply disables the optimization altogether?
> > > I myself don't see a better way, but thought I'd ask before proceeding
> > > with review and commit.
> >
> > If you don't see a clear path forward, then "disable" is the only
> > reasonable choice for the back branches.  Maybe we'll find a fix
> > in future, but it seems unlikely that it'd be back-patchable.
>
> Agreed.
>
> Here's patch v5 for the master branch (now up to f4694e0f), with no
> interesting changes other than fixing apply conflicts caused by
> bfe56cdf.

I noticed that Andres's comment from [1] is not yet addressed,
changing the commitfest entry status to Waiting on Author, please
address the comment and change it back to Needs review.
[1] - https://www.postgresql.org/message-id/tf5pp2o2a5x5qjcseq354bd26ya4o7p2vjzm5z4w57ca3vy6bc@ep7enrljvdkr

Regards,
Vignesh



Commits

  1. Add test for HeapBitmapScan's broken skip_fetch optimization

  2. Remove HeapBitmapScan's skip_fetch optimization

  3. Allow bitmap scans to operate as index-only scans when possible.