postgresql

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Tom Lane 1a179f36f7 Fix GEQO to not assume its join order heuristic always works. Back in commit `400e2c9344` I rewrote GEQO's gimme_tree function to improve its heuristic for modifying the given tour into a legal join order. In what can only be called a fit of hubris, I supposed that this new heuristic would always find a legal join order, and ripped out the old logic that allowed gimme_tree to sometimes fail. The folly of this is exposed by bug #12760, in which the "greedy" clumping behavior of merge_clump() can lead it into a dead end which could only be recovered from by un-clumping. We have no code for that and wouldn't know exactly what to do with it if we did. Rather than try to improve the heuristic rules still further, let's just recognize that it is a heuristic and probably must always have failure cases. So, put back the code removed in the previous commit to allow for failure (but comment it a bit better this time). It's possible that this code was actually fully correct at the time and has only been broken by the introduction of LATERAL. But having seen this example I no longer have much faith in that proposition, so back-patch to all supported branches.		2015-02-10 20:37:19 -05:00
config	Speed up CRC calculation using slicing-by-8 algorithm.	2015-02-10 10:54:40 +02:00
contrib	Move pg_crc.c to src/common, and remove pg_crc_tables.h	2015-02-09 11:17:56 +02:00
doc	Fixed array handling in ecpg.	2015-02-10 12:04:10 +01:00
src	Fix GEQO to not assume its join order heuristic always works.	2015-02-10 20:37:19 -05:00
.dir-locals.el	Update Emacs configuration	2013-08-13 20:08:44 -04:00
.gitattributes	Add functions for dealing with PGP armor header lines to pgcrypto.	2014-10-01 16:03:39 +03:00
.gitignore	Update .gitignore for config.cache.	2014-12-18 19:56:42 +09:00
aclocal.m4
configure	Speed up CRC calculation using slicing-by-8 algorithm.	2015-02-10 10:54:40 +02:00
configure.in	Speed up CRC calculation using slicing-by-8 algorithm.	2015-02-10 10:54:40 +02:00
COPYRIGHT	Update copyright for 2015	2015-01-06 11:43:47 -05:00
GNUmakefile.in	Add TAP tests for client programs	2014-04-14 21:33:46 -04:00
HISTORY	Improve text of stub HISTORY file.	2014-02-12 18:16:17 -05:00
Makefile
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

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/.