OSSForks/postgres
1
0
Fork 0
mirror of https://github.com/zebrajr/postgres.git synced 2025-12-06 12:20:15 +01:00
Code Issues Actions Packages Projects Releases Wiki Activity
Mirror of the official PostgreSQL GIT repository. Note that this is just a *mirror* - we don't work with pull requests on github. To contribute, please see https://wiki.postgresql.org/wiki/Submitting_a_Patch
60,660 Commits 34 Branches 537 Tags 1,009 MiB
C 85.1%
PLpgSQL 6%
Perl 4.6%
Yacc 1.2%
Meson 0.7%
Other 2.2%
5ead85fbc8
Go to file
Peter Geoghegan 5ead85fbc8 Show index search count in EXPLAIN ANALYZE. 
Expose the count of index searches/index descents in EXPLAIN ANALYZE's
output for index scan nodes.  This information is particularly useful
with scans that use ScalarArrayOp quals, where the number of index scans
isn't predictable in advance (at least not with optimizations like the
one added to nbtree by Postgres 17 commit 5bf748b8).  It will also be
useful when EXPLAIN ANALYZE shows details of an nbtree index scan that
uses skip scan optimizations set to be introduced by an upcoming patch.

The instrumentation works by teaching index AMs to increment a new
nsearches counter whenever a new index search begins.  The counter is
incremented at exactly the same point that index AMs must already
increment the index's pg_stat_*_indexes.idx_scan counter (we're counting
the same event, but at the scan level rather than the relation level).
The new counter is stored in the scan descriptor (IndexScanDescData),
which explain.c reaches by going through the scan node's PlanState.

This approach doesn't match the approach used when tracking other index
scan specific costs (e.g., "Rows Removed by Filter:").  It is similar to
the approach used in other cases where we must track costs that are only
readily accessible inside an access method, and not from the executor
(e.g., "Heap Blocks:" output for a Bitmap Heap Scan).  It is inherently
necessary to maintain a counter that can be incremented multiple times
during a single amgettuple call (or amgetbitmap call), and directly
exposing PlanState.instrument to index access methods seems unappealing.

Author: Peter Geoghegan <pg@bowt.ie>
Reviewed-By: Tomas Vondra <tomas@vondra.me>
Reviewed-By: Robert Haas <robertmhaas@gmail.com>
Reviewed-By: Masahiro Ikeda <ikedamsh@oss.nttdata.com>
Reviewed-By: Matthias van de Meent <boekewurm+postgres@gmail.com>
Discussion: https://postgr.es/m/CAH2-Wz=PKR6rB7qbx+Vnd7eqeB5VTcrW=iJvAsTsKbdG+kW_UA@mail.gmail.com
Discussion: https://postgr.es/m/CAH2-WzkRqvaqR2CTNqTZP0z6FuL4-3ED6eQB0yx38XBNj1v-4Q@mail.gmail.com
2025-03-05 09:36:48 -05:00
.github Add CODE_OF_CONDUCT.md, CONTRIBUTING.md, and SECURITY.md. 2024-07-02 13:03:58 -05:00
config Add support for OAUTHBEARER SASL mechanism 2025-02-20 16:25:17 +01:00
contrib Show index search count in EXPLAIN ANALYZE. 2025-03-05 09:36:48 -05:00
doc Show index search count in EXPLAIN ANALYZE. 2025-03-05 09:36:48 -05:00
src Show index search count in EXPLAIN ANALYZE. 2025-03-05 09:36:48 -05:00
.cirrus.star Remove duplicate words in docs and code comments. 2023-10-09 09:18:47 +05:30
.cirrus.tasks.yml ci: Use a RAM disk for NetBSD and OpenBSD. 2025-03-04 11:29:21 +13:00
.cirrus.yml ci: Test NetBSD and OpenBSD 2025-02-12 09:40:07 -05:00
.dir-locals.el Make Emacs perl-mode indent more like perltidy. 2019-01-13 11:32:31 -08:00
.editorconfig Add script to keep .editorconfig in sync with .gitattributes 2025-02-01 10:09:45 +01:00
.git-blame-ignore-revs Add commit 76aa615943 to .git-blame-ignore-revs 2025-02-01 16:48:18 +09:00
.gitattributes Add script to keep .editorconfig in sync with .gitattributes 2025-02-01 10:09:45 +01:00
.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 Add support for OAUTHBEARER SASL mechanism 2025-02-20 16:25:17 +01:00
configure.ac Add support for OAUTHBEARER SASL mechanism 2025-02-20 16:25:17 +01:00
COPYRIGHT Update copyright for 2025 2025-01-01 11:21:55 -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 Remove AIX support 2024-02-28 15:17:23 +04:00
meson_options.txt Add support for OAUTHBEARER SASL mechanism 2025-02-20 16:25:17 +01:00
meson.build Make test portlock logic work with meson 2025-02-21 11:25:05 -05:00
README.md Revise the style of a paragraph in README.md. 2024-03-21 10:16:41 -05:00

README.md

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/.