rdelaage
/
postgresql
mirror of https://git.postgresql.org/git/postgresql.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity
55,770 Commits 36 Branches 606 Tags 423 MiB
C 86%
PLpgSQL 5.5%
Perl 4.1%
Yacc 1.3%
Makefile 0.7%
Other 2.3%
Go to file
Thomas Munro 8d578b9b2e Fix race in parallel hash join batch cleanup, take II. 
With unlucky timing and parallel_leader_participation=off (not the
default), PHJ could attempt to access per-batch shared state just as it
was being freed.  There was code intended to prevent that by checking
for a cleared pointer, but it was racy.  Fix, by introducing an extra
barrier phase.  The new phase PHJ_BUILD_RUNNING means that it's safe to
access the per-batch state to find a batch to help with, and
PHJ_BUILD_DONE means that it is too late.  The last to detach will free
the array of per-batch state as before, but now it will also atomically
advance the phase, so that late attachers can avoid the hazard.  This
mirrors the way per-batch hash tables are freed (see phases
PHJ_BATCH_PROBING and PHJ_BATCH_DONE).

An earlier attempt to fix this (commit 3b8981b6, later reverted) missed
one special case.  When the inner side is empty (the "empty inner
optimization), the build barrier would only make it to
PHJ_BUILD_HASHING_INNER phase before workers attempted to detach from
the hashtable.  In that case, fast-forward the build barrier to
PHJ_BUILD_RUNNING before proceeding, so that our later assertions hold
and we can still negotiate who is cleaning up.

Revealed by build farm failures, where BarrierAttach() failed a sanity
check assertion, because the memory had been clobbered by dsa_free().
In non-assert builds, the result could be a segmentation fault.

Back-patch to all supported releases.

Author: Thomas Munro <thomas.munro@gmail.com>
Author: Melanie Plageman <melanieplageman@gmail.com>
Reported-by: Michael Paquier <michael@paquier.xyz>
Reported-by: David Geier <geidav.pg@gmail.com>
Tested-by: David Geier <geidav.pg@gmail.com>
Discussion: https://postgr.es/m/20200929061142.GA29096%40paquier.xyz
 		2023-03-21 14:29:34 +13:00
config autoconf: Move export_dynamic determination to configure 2022-12-06 18:55:28 -08:00
contrib Fix t_isspace(), etc., when datlocprovider=i and datctype=C. 2023-03-17 12:08:46 -07:00
doc meson: rename html_help target to htmlhelp 2023-03-20 17:23:57 -07:00
src Fix race in parallel hash join batch cleanup, take II. 2023-03-21 14:29:34 +13:00
.cirrus.yml cirrus/ccache: Use G rather than GB suffix 2023-03-13 07:23:45 +01:00
.dir-locals.el Make Emacs perl-mode indent more like perltidy. 2019-01-13 11:32:31 -08:00
.editorconfig Add .editorconfig 2019-12-18 09:13:13 +01:00
.git-blame-ignore-revs Add b6dfee28 to .git-blame-ignore-revs 2023-03-09 19:26:03 +09:00
.gitattributes gitattributes: Ignore imported pg_bsd_indent code for whitespace checks 2023-02-22 09:00:28 +01:00
.gitignore Update top-level .gitignore. 2022-12-04 15:23:00 -05:00
COPYRIGHT Update copyright for 2023 2023-01-02 15:00:37 -05:00
GNUmakefile.in Integrate pg_bsd_indent into our build/test infrastructure. 2023-02-12 12:22:21 -05:00
HISTORY Canonicalize some URLs 2020-02-10 20:47:50 +01:00
Makefile Dynamically find correct installation docs in Makefile. 2022-01-19 14:48:25 +01:00
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
aclocal.m4 autoconf: Move export_dynamic determination to configure 2022-12-06 18:55:28 -08:00
configure libpq: Remove code for SCM credential authentication 2023-03-17 10:52:26 +09:00
configure.ac libpq: Remove code for SCM credential authentication 2023-03-17 10:52:26 +09:00
meson.build libpq: Remove code for SCM credential authentication 2023-03-17 10:52:26 +09:00
meson_options.txt meson: Make auto the default of the ssl option 2023-03-13 07:04:11 +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/.