Re: Incorrect result of bitmap heap scan.

Andres Freund <andres@anarazel.de>

From: Andres Freund <andres@anarazel.de>

To: Matthias van de Meent <boekewurm+postgres@gmail.com>, Andrew Dunstan <andrew@dunslane.net>, Melanie Plageman <melanieplageman@gmail.com>, Thomas Munro <thomas.munro@gmail.com>, Peter Geoghegan <pg@bowt.ie>

Cc: Konstantin Knizhnik <knizhnik@garret.ru>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>, Alexander Kuzmenkov <akuzmenkov@timescale.com>, Tom Lane <tgl@sss.pgh.pa.us>

Date: 2024-12-02T19:42:58Z

Lists: pgsql-hackers

Attachments

v1-0001-isolationtester-showing-broken-index-only-bitmap-.patch (text/x-diff)

Hi,

On 2024-12-02 11:31:48 -0500, Andres Freund wrote:
> I think it'd be good if we added a test that shows the failure mechanism so
> that we don't re-introduce this in the future. Evidently this failure isn't
> immediately obvious...

Attached is an isolationtest that reliably shows wrong query results.

Greetings,

Andres Freund

Commits

Add test for HeapBitmapScan's broken skip_fetch optimization
- 24da5b239a4b 18.0 landed
Remove HeapBitmapScan's skip_fetch optimization
- 459e7bf8e2f8 18.0 landed
- b9ec8125d167 13.21 landed
- 4934d38759cd 14.18 landed
- 77d90d6d6334 15.13 landed
- 980727b84107 16.9 landed
- 78cb2466f752 17.5 landed
Allow bitmap scans to operate as index-only scans when possible.
- 7c70996ebf09 11.0 cited