Vectorize pg_visibility.pg_visibility_map_summary

Matthias van de Meent <boekewurm+postgres@gmail.com>

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From: Matthias van de Meent <boekewurm+postgres@gmail.com>

To: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>

Cc: Nathan Bossart <nathandbossart@gmail.com>, Ants Aasma <ants.aasma@cybertec.at>

Date: 2025-12-22T21:28:09Z

Lists: pgsql-hackers

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v1-0001-pg_visibility-Use-visibilitymap_count-instead-of-.patch (application/octet-stream)

Hi,

Whilst working on fixing a bug in GiST and SP-GiST's index-only scan
systems, I noticed that pg_visibility is sometimes rather wasteful
with the APIs which it calls into; especially now that there are more
optimized APIs available.

Here's one small patch that makes it use the visibilitymap_count() API
for pg_visibility_map_summary(), replacing its own bespoke counting
mechanism with the primary implementation that has vectorized
optimizations, thus reducing the overhead of
pg_visibility_map_summary.

CC-ed to authors of 41c51f0c68, visibilitymap_count was optimized, and
this potential user wasn't notified of that.


Kind regards,

Matthias van de Meent
Databricks (https://www.databricks.com)