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Tomas Vondra 9c18b47e61 Fix BitmapHeapScan non-parallel-aware EXPLAIN ANALYZE
Allocates shared bitmap table scan instrumentation for all parallel
scans. Previously, the instrumentation was only allocated for
parallel-aware scans, other bitmap heap scans in the parallel query had
no shared instrumentation and EXPLAIN didn't report exact/lossy pages.
This affected cases like scans on the outside of a parallel join or
queries run with debug_parallel_query=regress.

Fixed by allocating a separate DSM chunk for shared instrumentation and
doing so regardless of parallel-awareness. The instrumentation is
allocated in its own DSM chunk, separate from ParallelBitmapHeapState.

Report an initial patch by me. The approach with a separate DSM was
proposed and implemented by Melanie.

Not backpatched. The issue affects Postgres 18 (since 5a1e6df3b8), but
having multiple DSM chunks is possible only since dd78e69cfc. If we
decide to fix this in backbranches too, it will need to be done in a
less invasive way.

Author: Melanie Plageman <melanieplageman@gmail.com>
Reviewed-by: Tomas Vondra <tomas@vondra.me>
Reviewed-by: Lukas Fittl <lukas@fittl.com>
Discussion: https://postgr.es/m/flat/a177a6dd-240b-455a-8f25-aca0b1c08c6e%40vondra.me
2026-04-07 12:47:13 +02:00
.github Add CODE_OF_CONDUCT.md, CONTRIBUTING.md, and SECURITY.md. 2024-07-02 13:03:58 -05:00
config Compute CRC32C on ARM using the Crypto Extension where available 2026-04-04 20:47:01 +07:00
contrib Allow logical replication snapshots to be database-specific 2026-04-07 12:31:18 +02:00
doc Allow logical replication snapshots to be database-specific 2026-04-07 12:31:18 +02:00
src Fix BitmapHeapScan non-parallel-aware EXPLAIN ANALYZE 2026-04-07 12:47:13 +02:00
.cirrus.star ci: Simplify ci-os-only handling 2025-08-14 12:09:34 -04:00
.cirrus.tasks.yml Enable test_cplusplusext with MSVC 2026-04-01 07:48:47 +02:00
.cirrus.yml ci: Per-repo configuration for manually trigger tasks 2025-08-14 11:54:03 -04:00
.dir-locals.el Make Emacs perl-mode indent more like perltidy. 2019-01-13 11:32:31 -08:00
.editorconfig Update .editorconfig and .gitattributes for postgresql.conf.sample. 2025-11-18 10:28:36 -06:00
.git-blame-ignore-revs Add commit 874da8b1f6 to .git-blame-ignore-revs. 2026-03-30 14:35:24 -05:00
.gitattributes Update .editorconfig and .gitattributes for postgresql.conf.sample. 2025-11-18 10:28:36 -06:00
.gitignore Update top-level .gitignore. 2022-12-04 15:23:00 -05:00
.mailmap Add a Git .mailmap file 2024-11-05 13:56:02 +01:00
aclocal.m4 autoconf: Move export_dynamic determination to configure 2022-12-06 18:55:28 -08:00
configure Compute CRC32C on ARM using the Crypto Extension where available 2026-04-04 20:47:01 +07:00
configure.ac Compute CRC32C on ARM using the Crypto Extension where available 2026-04-04 20:47:01 +07:00
COPYRIGHT Update copyright for 2026 2026-01-01 13:24:10 -05:00
GNUmakefile.in Allow selecting the git revision to be packaged by "make dist". 2024-05-03 11:08:50 -04:00
HISTORY Canonicalize some URLs 2020-02-10 20:47:50 +01:00
Makefile Restore AIX support. 2026-02-23 13:34:22 -05:00
meson.build Compute CRC32C on ARM using the Crypto Extension where available 2026-04-04 20:47:01 +07:00
meson_options.txt Update copyright for 2026 2026-01-01 13:24:10 -05:00
README.md Revise the style of a paragraph in README.md. 2024-03-21 10:16:41 -05:00

PostgreSQL Database Management System

This directory contains the source code distribution of the PostgreSQL database management system.

PostgreSQL is an advanced object-relational database management system that supports an extended subset of the SQL standard, including transactions, foreign keys, subqueries, triggers, user-defined types and functions. This distribution also contains C language bindings.

Copyright and license information can be found in the file COPYRIGHT.

General documentation about this version of PostgreSQL can be found at https://www.postgresql.org/docs/devel/. In particular, information about building PostgreSQL from the source code can be found at https://www.postgresql.org/docs/devel/installation.html.

The latest version of this software, and related software, may be obtained at https://www.postgresql.org/download/. For more information look at our web site located at https://www.postgresql.org/.