rdelaage
/
postgresql
mirror of https://git.postgresql.org/git/postgresql.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity
42,445 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
Tom Lane 16ebab6886 Avoid transferring parallel-unsafe subplans to parallel workers. 
Commit 5e6d8d2bb allowed parallel workers to execute parallel-safe
subplans, but it transmitted the query's entire list of subplans to
the worker(s).  Since execMain.c blindly does ExecInitNode and later
ExecEndNode on every list element, this resulted in parallel-unsafe plan
nodes nonetheless getting started up and shut down in parallel workers.
That seems mostly harmless as far as core plan node types go (but
maybe not so much for Gather?).  But it resulted in postgres_fdw
opening and then closing extra remote connections, and it's likely
that other non-parallel-safe FDWs or custom scan providers would have
worse reactions.

To fix, just make ExecSerializePlan replace parallel-unsafe subplans
with NULLs in the cut-down plan tree that it transmits to workers.
This relies on ExecInitNode and ExecEndNode to do nothing on NULL
input, but they do anyway.  If anything else is touching the dropped
subplans in a parallel worker, that would be a bug to be fixed.
(This thus provides a strong guarantee that we won't try to do
something with a parallel-unsafe subplan in a worker.)

This is, I think, the last fix directly occasioned by Andreas Seltenreich's
bug report of a few days ago.

Tom Lane and Amit Kapila

Discussion: https://postgr.es/m/87tw5x4vcu.fsf@credativ.de
 		2017-04-12 16:07:00 -04:00
config Remove use of Jade and DSSSL 2017-04-06 22:09:11 -04:00
contrib Fix pgstattuple's handling of unused hash pages. 2017-04-12 11:53:00 -04:00
doc doc: Tweak CSS 2017-04-12 15:41:41 -04:00
src Avoid transferring parallel-unsafe subplans to parallel workers. 2017-04-12 16:07:00 -04:00
.dir-locals.el emacs: Set indent-tabs-mode in perl-mode 2015-04-12 23:53:23 -04:00
.gitattributes Remove contrib/tsearch2. 2017-02-13 11:06:11 -05:00
.gitignore Allow .so minor version numbers above 9 in .gitignore. 2016-08-15 17:35:35 -04:00
COPYRIGHT Update copyright for 2017 2017-01-03 12:37:53 -05:00
GNUmakefile.in Have "make coverage" recurse into contrib as well 2016-09-05 18:44:36 -03:00
HISTORY Improve text of stub HISTORY file. 2014-02-12 18:16:17 -05:00
Makefile Allow make check in PL directories 2011-02-15 06:52:12 +02:00
README Don't generate plain-text HISTORY and src/test/regress/README anymore. 2014-02-10 20:48:04 -05:00
README.git Don't generate plain-text HISTORY and src/test/regress/README anymore. 2014-02-10 20:48:04 -05:00
aclocal.m4 ICU support 2017-03-23 15:28:48 -04:00
configure Remove use of Jade and DSSSL 2017-04-06 22:09:11 -04:00
configure.in Remove use of Jade and DSSSL 2017-04-06 22:09:11 -04:00

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:

	http://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
http://www.postgresql.org/download/.  For more information look at our
web site located at http://www.postgresql.org/.