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Tom Lane 964c0d0f80 Prevent pushing down WHERE clauses into unsafe UNION/INTERSECT nests. 
The planner is aware that it mustn't push down upper-level quals into
subqueries if the quals reference subquery output columns that contain
set-returning functions or volatile functions, or are non-DISTINCT outputs
of a DISTINCT ON subquery.  However, it missed making this check when
there were one or more levels of UNION or INTERSECT above the dangerous
expression.  This could lead to "set-valued function called in context that
cannot accept a set" errors, as seen in bug #8213 from Eric Soroos, or to
silently wrong answers in the other cases.

To fix, refactor the checks so that we make the column-is-unsafe checks
during subquery_is_pushdown_safe(), which already has to recursively
inspect all arms of a set-operation tree.  This makes
qual_is_pushdown_safe() considerably simpler, at the cost that we will
spend some cycles checking output columns that possibly aren't referenced
in any upper qual.  But the cases where this code gets executed at all
are already nontrivial queries, so it's unlikely anybody will notice any
slowdown of planning.

This has been broken since commit 05f916e6ad,
which makes the bug over ten years old.  A bit surprising nobody noticed it
before now.
2013-06-05 23:45:11 -04:00
config Compiler optimizations for page checksum code. 2013-04-30 06:59:26 +01:00
contrib Fix off-by-one in pg_xlogdump -r option. 2013-06-04 18:51:43 +03:00
doc Another man page whitespace fix 2013-06-01 22:22:02 -04:00
src Prevent pushing down WHERE clauses into unsafe UNION/INTERSECT nests. 2013-06-05 23:45:11 -04:00
.gitignore Add pkg-config files for libpq and ecpg libraries 2013-03-31 16:58:40 -04:00
aclocal.m4
configure Stamp 9.3beta1. 2013-05-06 16:57:06 -04:00
configure.in Stamp 9.3beta1. 2013-05-06 16:57:06 -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

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/.