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Mirror of the main PostgreSQL git repository.
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Tom Lane cffd89ca73 Revise the planner's handling of "pseudoconstant" WHERE clauses, that is 
clauses containing no variables and no volatile functions.  Such a clause
can be used as a one-time qual in a gating Result plan node, to suppress
plan execution entirely when it is false.  Even when the clause is true,
putting it in a gating node wins by avoiding repeated evaluation of the
clause.  In previous PG releases, query_planner() would do this for
pseudoconstant clauses appearing at the top level of the jointree, but
there was no ability to generate a gating Result deeper in the plan tree.
To fix it, get rid of the special case in query_planner(), and instead
process pseudoconstant clauses through the normal RestrictInfo qual
distribution mechanism.  When a pseudoconstant clause is found attached to
a path node in create_plan(), pull it out and generate a gating Result at
that point.  This requires special-casing pseudoconstants in selectivity
estimation and cost_qual_eval, but on the whole it's pretty clean.
It probably even makes the planner a bit faster than before for the normal
case of no pseudoconstants, since removing pull_constant_clauses saves one
useless traversal of the qual tree.  Per gripe from Phil Frost.
2006-07-01 18:38:33 +00:00
config Emit warnings for unknown configure options. 2006-05-30 13:52:25 +00:00
contrib Changes 2006-06-28 12:00:14 +00:00
doc Update item for GUID: 2006-06-30 15:04:32 +00:00
src Revise the planner's handling of "pseudoconstant" WHERE clauses, that is 2006-07-01 18:38:33 +00:00
aclocal.m4 Add new auto-detection of thread flags. 2004-04-23 18:15:55 +00:00
configure Don't try to call posix_fadvise() unless <fcntl.h> supplies a declaration 2006-06-18 18:30:21 +00:00
configure.in Don't try to call posix_fadvise() unless <fcntl.h> supplies a declaration 2006-06-18 18:30:21 +00:00
COPYRIGHT Update copyright for 2006. Update scripts. 2006-03-05 15:59:11 +00:00
GNUmakefile.in Build src/test/regress/README during tarball making like the other 2006-04-06 18:54:37 +00:00
Makefile please find attached an alternate submission which addresses open item 2004-10-06 08:50:02 +00:00
README Update README file. 2006-02-12 19:24:24 +00:00
README.CVS Some further editorializing on README.CVS. 2004-03-28 06:09:08 +00:00

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 including some of the more
common listed below:

C++ - http://thaiopensource.org/development/libpqxx/
JDBC - http://jdbc.postgresql.org
ODBC - http://odbc.postgresql.org
Perl - http://search.cpan.org/~dbdpg/
PHP - http://www.php.net
Python - http://www.initd.org/
Ruby - http://ruby.scripting.ca/postgres/

Other language binding are available from a variety of contributing
parties.

PostgreSQL also has a great number of procedural languages available,
a short but not complete list is below:

pl/c - Included in PostgreSQL core 
plPgsql - Included in PostgreSQL core - Similar to Oracle PL/sql
plPerl - Included in PostgreSQL core
plPHP - http://projects.commandprompt.com/projects/public/plphp
plPython - Included in PostgreSQL core
plJava - http://gborg.postgresql.org/project/pljava/projdisplay.php
plTcl - Included in PostgreSQL core

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/.