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Tomas Vondra 36c4bc6e72 Ignore extended statistics for inheritance trees 
Since commit 859b3003de we only build extended statistics for individual
relations, ignoring the child relations. This resolved the issue with
updating catalog tuple twice, but we still tried to use the statistics
when calculating estimates for the whole inheritance tree. When the
relations contain very distinct data, it may produce bogus estimates.

This is roughly the same issue 427c6b5b9 addressed ~15 years ago, and we
fix it the same way - by ignoring extended statistics when calculating
estimates for the inheritance tree as a whole. We still consider
extended statistics when calculating estimates for individual child
relations, of course.

This may result in plan changes due to different estimates, but if the
old statistics were not describing the inheritance tree particularly
well it's quite likely the new plans is actually better.

Report and patch by Justin Pryzby, minor fixes and cleanup by me.
Backpatch all the way back to PostgreSQL 10, where extended statistics
were introduced (same as 859b3003de).

Author: Justin Pryzby
Reported-by: Justin Pryzby
Backpatch-through: 10
Discussion: https://postgr.es/m/20210923212624.GI831%40telsasoft.com
2022-01-15 02:20:54 +01:00
config Pacify perlcritic. 2021-11-22 15:57:31 -05:00
contrib Include permissive/enforcing state in sepgsql log messages. 2022-01-12 14:23:13 -05:00
doc Unify VACUUM VERBOSE and autovacuum logging. 2022-01-14 16:50:34 -08:00
src Ignore extended statistics for inheritance trees 2022-01-15 02:20:54 +01:00
.cirrus.yml ci: windows: run initdb with --no-sync. 2022-01-13 10:56:41 -08:00
.dir-locals.el
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.git-blame-ignore-revs Add another old commit to git-blame-ignore-revs. 2021-11-03 17:34:19 -07:00
.gitattributes gitattributes: Add new entry to silence whitespace error 2021-06-05 07:57:31 +02:00
.gitignore
aclocal.m4 Probe $PROVE not $PERL while checking for modules needed by TAP tests. 2021-11-22 12:54:52 -05:00
configure Make EXEC_BACKEND more convenient on Linux and FreeBSD. 2022-01-11 00:04:33 +13:00
configure.ac Make EXEC_BACKEND more convenient on Linux and FreeBSD. 2022-01-11 00:04:33 +13:00
COPYRIGHT Update copyright for 2022 2022-01-07 19:04:57 -05:00
GNUmakefile.in add missing tag from commit b8c4261e5e 2021-07-01 15:47:46 -04:00
HISTORY Canonicalize some URLs 2020-02-10 20:47:50 +01:00
Makefile
README Canonicalize some URLs 2020-02-10 20:47:50 +01:00
README.git Canonicalize some URLs 2020-02-10 20:47:50 +01:00

README 

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.

PostgreSQL has many language interfaces, many of which are listed here:

	https://www.postgresql.org/download/

See the file INSTALL for instructions on how to build and install
PostgreSQL.  That file also lists supported operating systems and
hardware platforms and contains information regarding any other
software packages that are required to build or run the PostgreSQL
system.  Copyright and license information can be found in the
file COPYRIGHT.  A comprehensive documentation set is included in this
distribution; it can be read as described in the installation
instructions.

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