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Alvaro Herrera d4cef0aa2a Improve vacuum code to track minimum Xids per table instead of per database.
To this end, add a couple of columns to pg_class, relminxid and relvacuumxid,
based on which we calculate the pg_database columns after each vacuum.

We now force all databases to be vacuumed, even template ones.  A backend
noticing too old a database (meaning pg_database.datminxid is in danger of
falling behind Xid wraparound) will signal the postmaster, which in turn will
start an autovacuum iteration to process the offending database.  In principle
this is only there to cope with frozen (non-connectable) databases without
forcing users to set them to connectable, but it could force regular user
database to go through a database-wide vacuum at any time.  Maybe we should
warn users about this somehow.  Of course the real solution will be to use
autovacuum all the time ;-)

There are some additional improvements we could have in this area: for example
the vacuum code could be smarter about not updating pg_database for each table
when called by autovacuum, and do it only once the whole autovacuum iteration
is done.

I updated the system catalogs documentation, but I didn't modify the
maintenance section.  Also having some regression tests for this would be nice
but it's not really a very straightforward thing to do.

Catalog version bumped due to system catalog changes.
2006-07-10 16:20:52 +00:00
config Emit warnings for unknown configure options. 2006-05-30 13:52:25 +00:00
contrib Add index information to /contrib/pgstattuple: 2006-07-06 02:18:07 +00:00
doc Improve vacuum code to track minimum Xids per table instead of per database. 2006-07-10 16:20:52 +00:00
src Improve vacuum code to track minimum Xids per table instead of per database. 2006-07-10 16:20:52 +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 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

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/.