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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
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
.gitignore Add *.pot to .gitignore 2013-10-19 10:56:52 -04:00
aclocal.m4
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
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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/.