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Tom Lane a916cb9d5a Avoid overflow hazard when clamping group counts to "long int".
Several places in the planner tried to clamp a double value to fit
in a "long" by doing
	(long) Min(x, (double) LONG_MAX);
This is subtly incorrect, because it casts LONG_MAX to double and
potentially back again.  If long is 64 bits then the double value
is inexact, and the platform might round it up to LONG_MAX+1
resulting in an overflow and an undesirably negative output.

While it's not hard to rewrite the expression into a safe form,
let's put it into a common function to reduce the risk of someone
doing it wrong in future.

In principle this is a bug fix, but since the problem could only
manifest with group count estimates exceeding 2^63, it seems unlikely
that anyone has actually hit this or will do so anytime soon.  We're
fixing it mainly to satisfy fuzzer-type tools.  That being the case,
a HEAD-only fix seems sufficient.

Andrey Lepikhov

Discussion: https://postgr.es/m/ebbc2efb-7ef9-bf2f-1ada-d6ec48f70e58@postgrespro.ru
2022-05-21 13:13:44 -04:00
config Pre-beta mechanical code beautification. 2022-05-12 15:17:30 -04:00
contrib Add a new shmem_request_hook hook. 2022-05-13 09:31:06 -04:00
doc doc: Mention pg_read_all_stats in description of track_activities 2022-05-21 19:05:47 +09:00
src Avoid overflow hazard when clamping group counts to "long int". 2022-05-21 13:13:44 -04:00
.cirrus.yml Make upgradecheck a no-op in MSVC's vcregress.pl 2022-04-02 12:06:11 +09:00
.dir-locals.el
.editorconfig
.git-blame-ignore-revs Add 23e7b38bf to git-blame-ignore-revs. 2022-05-12 15:22:20 -04:00
.gitattributes Remove trailing whitespace from *.sgml files. 2022-04-20 11:04:49 -04:00
.gitignore
aclocal.m4 Probe $PROVE not $PERL while checking for modules needed by TAP tests. 2021-11-22 12:54:52 -05:00
configure Stamp 15beta1. 2022-05-16 17:10:42 -04:00
configure.ac Stamp 15beta1. 2022-05-16 17:10:42 -04:00
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
Makefile Dynamically find correct installation docs in Makefile. 2022-01-19 14:48:25 +01:00
README
README.git

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/.