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Tom Lane 69cc60dcfd Guard against input_rows == 0 in estimate_num_groups().
This case doesn't normally happen, because the planner usually clamps
all row estimates to at least one row; but I found that it can arise
when dealing with relations excluded by constraints.  Without a defense,
estimate_num_groups() can return zero, which leads to divisions by zero
inside the planner as well as assertion failures in the executor.

An alternative fix would be to change set_dummy_rel_pathlist() to make
the size estimate for a dummy relation 1 row instead of 0, but that seemed
pretty ugly; and probably someday we'll want to drop the convention that
the minimum rowcount estimate is 1 row.

Back-patch to 8.4, as the problem can be demonstrated that far back.
2013-05-10 17:15:30 -04:00
config Compiler optimizations for page checksum code. 2013-04-30 06:59:26 +01:00
contrib Fix pgp_pub_decrypt() so it works for secret keys with passwords. 2013-05-10 13:06:48 -04:00
doc Update key words table for 9.3 2013-05-09 22:26:04 -04:00
src Guard against input_rows == 0 in estimate_num_groups(). 2013-05-10 17:15:30 -04:00
.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 9.3beta1. 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 Trivial typo fix. 2010-09-21 14:16:00 -04:00

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/.