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Tom Lane 5e900bc00f Fix generation of MergeAppend plans for optimized min/max on expressions. Before jamming a desired targetlist into a plan node, one really ought to make sure the plan node can handle projections, and insert a buffering Result plan node if not. planagg.c forgot to do this, which is a hangover from the days when it only dealt with IndexScan plan types. MergeAppend doesn't project though, not to mention that it gets unhappy if you remove its possibly-resjunk sort columns. The code accidentally failed to fail for cases in which the min/max argument was a simple Var, because the new targetlist would be equivalent to the original "flat" tlist anyway. For any more complex case, it's been broken since 9.1 where we introduced the ability to optimize min/max using MergeAppend, as reported by Raphael Bauduin. Fix by duplicating the logic from grouping_planner that decides whether we need a Result node. In 9.2 and 9.1, this requires back-porting the tlist_same_exprs() function introduced in commit `4387cf956b`, else we'd uselessly add a Result node in cases that worked before. It's rather tempting to back-patch that whole commit so that we can avoid extra Result nodes in mainline cases too; but I'll refrain, since that code hasn't really seen all that much field testing yet.		2013-11-07 13:14:14 -05:00
config	Remove maintainer-check target, fold into normal build	2013-10-10 20:11:56 -04:00
contrib	Use appendStringInfoString instead of appendStringInfo where possible.	2013-10-31 10:55:59 -04:00
doc	Support default arguments and named-argument notation for window functions.	2013-11-06 13:33:09 -05:00
src	Fix generation of MergeAppend plans for optimized min/max on expressions.	2013-11-07 13:14:14 -05:00
.dir-locals.el	Update Emacs configuration	2013-08-13 20:08:44 -04:00
.gitignore	Add *.pot to .gitignore	2013-10-19 10:56:52 -04:00
aclocal.m4	Remove cvs keywords from all files.	2010-09-20 22:08:53 +02:00
configure	Get rid of use of asprintf() in favor of a more portable implementation.	2013-10-22 18:42:13 -04:00
configure.in	Get rid of use of asprintf() in favor of a more portable implementation.	2013-10-22 18:42:13 -04:00
COPYRIGHT	Update copyrights for 2013	2013-01-01 17:15:01 -05:00
GNUmakefile.in	Remove maintainer-check target, fold into normal build	2013-10-10 20:11:56 -04:00
Makefile	Allow make check in PL directories	2011-02-15 06:52:12 +02:00
README	Remove useless whitespace at end of lines	2010-11-23 22:34:55 +02:00
README.git	Trivial typo fix.	2010-09-21 14:16:00 -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.  Changes between all PostgreSQL releases are recorded in the
file HISTORY.  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/.