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Tomas Vondra 2a307df1bb Fix ndistinct estimates with system attributes
When estimating the number of groups using extended statistics, the code
was discarding information about system attributes. This led to strange
situation that

    SELECT 1 FROM t GROUP BY ctid;

could have produced higher estimate (equal to pg_class.reltuples) than

    SELECT 1 FROM t GROUP BY a, b, ctid;

with extended statistics on (a,b). Fixed by retaining information about
the system attribute.

Backpatch all the way to 10, where extended statistics were introduced.

Author: Tomas Vondra
Backpatch-through: 10
2021-03-26 22:44:01 +01:00
config jit: configure: Explicitly reference 'native' component. 2020-12-07 18:40:27 -08:00
contrib Fix permission checks on constraint violation errors on partitions. 2021-02-08 11:01:55 +02:00
doc Use correct spelling of statistics kind 2021-03-23 04:56:17 +01:00
src Fix ndistinct estimates with system attributes 2021-03-26 22:44:01 +01:00
.dir-locals.el Make Emacs perl-mode indent more like perltidy. 2019-01-13 11:32:36 -08:00
.gitattributes Remove contrib/tsearch2. 2017-02-13 11:06:11 -05:00
.gitignore Support for optimizing and emitting code in LLVM JIT provider. 2018-03-22 11:05:22 -07:00
COPYRIGHT Update copyright for 2021 2021-01-02 13:06:24 -05:00
GNUmakefile.in Make install-tests target work with vpath builds 2020-05-31 18:35:21 -04:00
HISTORY Change documentation references to PG website to use https: not http: 2017-05-20 21:50:47 -04:00
Makefile Don't unset MAKEFLAGS in non-GNU Makefile. 2019-06-25 09:40:20 +12:00
README Change documentation references to PG website to use https: not http: 2017-05-20 21:50:47 -04:00
README.git Change documentation references to PG website to use https: not http: 2017-05-20 21:50:47 -04:00
aclocal.m4 Remove configure-time probe for DocBook DTD. 2020-11-30 15:24:13 -05:00
configure Stamp 11.11. 2021-02-08 16:57:36 -05:00
configure.in Stamp 11.11. 2021-02-08 16:57:36 -05:00

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/.