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Tom Lane 1c0dfaa68f Compute correct em_nullable_relids in get_eclass_for_sort_expr(). Bug #8591 from Claudio Freire demonstrates that get_eclass_for_sort_expr must be able to compute valid em_nullable_relids for any new equivalence class members it creates. I'd worried about this in the commit message for `db9f0e1d9a`, but claimed that it wasn't a problem because multi-member ECs should already exist when it runs. That is transparently wrong, though, because this function is also called by initialize_mergeclause_eclasses, which runs during deconstruct_jointree. The example given in the bug report (which the new regression test item is based upon) fails because the COALESCE() expression is first seen by initialize_mergeclause_eclasses rather than process_equivalence. Fixing this requires passing the appropriate nullable_relids set to get_eclass_for_sort_expr, and it requires new code to compute that set for top-level expressions such as ORDER BY, GROUP BY, etc. We store the top-level nullable_relids in a new field in PlannerInfo to avoid computing it many times. In the back branches, I've added the new field at the end of the struct to minimize ABI breakage for planner plugins. There doesn't seem to be a good alternative to changing get_eclass_for_sort_expr's API signature, though. There probably aren't any third-party extensions calling that function directly; moreover, if there are, they probably need to think about what to pass for nullable_relids anyway. Back-patch to 9.2, like the previous patch in this area.		2013-11-15 16:46:21 -05:00
config	Compiler optimizations for page checksum code.	2013-04-30 06:59:26 +01:00
contrib	Work around NetBSD shell issue in pg_upgrade test script.	2013-10-28 11:51:44 -04:00
doc	doc: Restore proper alphabetical order.	2013-11-15 08:55:45 -05:00
src	Compute correct em_nullable_relids in get_eclass_for_sort_expr().	2013-11-15 16:46:21 -05:00
.gitignore	Add pkg-config files for libpq and ecpg libraries	2013-03-31 16:58:40 -04:00
aclocal.m4	Remove cvs keywords from all files.	2010-09-20 22:08:53 +02:00
configure	Stamp 9.3.1.	2013-10-07 23:17:38 -04:00
configure.in	Stamp 9.3.1.	2013-10-07 23:17:38 -04:00
COPYRIGHT	Update copyrights for 2013	2013-01-01 17:15:01 -05:00
GNUmakefile.in	Make init-po and update-po recursive make targets	2012-06-29 14:01:54 +03:00
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	Fix doc links in README file to work with new website layout	2013-11-12 12:54:09 +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:

	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/.