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Tom Lane 8a30cc2127 Make the planner estimate costs for nestloop inner indexscans on the basis 
that the Mackert-Lohmann formula applies across all the repetitions of the
nestloop, not just each scan independently.  We use the M-L formula to
estimate the number of pages fetched from the index as well as from the table;
that isn't what it was designed for, but it seems reasonably applicable
anyway.  This makes large numbers of repetitions look much cheaper than
before, which accords with many reports we've received of overestimation
of the cost of a nestloop.  Also, change the index access cost model to
charge random_page_cost per index leaf page touched, while explicitly
not counting anything for access to metapage or upper tree pages.  This
may all need tweaking after we get some field experience, but in simple
tests it seems to be giving saner results than before.  The main thing
is to get the infrastructure in place to let cost_index() and amcostestimate
functions take repeated scans into account at all.  Per my recent proposal.

Note: this patch changes pg_proc.h, but I did not force initdb because
the changes are basically cosmetic --- the system does not look into
pg_proc to decide how to call an index amcostestimate function, and
there's no way to call such a function from SQL at all.
 		2006-06-06 17:59:58 +00:00
config Emit warnings for unknown configure options. 2006-05-30 13:52:25 +00:00
contrib Allow do not lexize words in substitution. 2006-06-06 16:25:55 +00:00
doc Make the planner estimate costs for nestloop inner indexscans on the basis 2006-06-06 17:59:58 +00:00
src Make the planner estimate costs for nestloop inner indexscans on the basis 2006-06-06 17:59:58 +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
aclocal.m4 Add new auto-detection of thread flags. 2004-04-23 18:15:55 +00:00
configure Emit warnings for unknown configure options. 2006-05-30 13:52:25 +00:00
configure.in Emit warnings for unknown configure options. 2006-05-30 13:52:25 +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/.