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Heikki Linnakangas 608195a3a3 Introduce visibility map. The visibility map is a bitmap with one bit per 
heap page, where a set bit indicates that all tuples on the page are
visible to all transactions, and the page therefore doesn't need
vacuuming. It is stored in a new relation fork.

Lazy vacuum uses the visibility map to skip pages that don't need
vacuuming. Vacuum is also responsible for setting the bits in the map.
In the future, this can hopefully be used to implement index-only-scans,
but we can't currently guarantee that the visibility map is always 100%
up-to-date.

In addition to the visibility map, there's a new PD_ALL_VISIBLE flag on
each heap page, also indicating that all tuples on the page are visible to
all transactions. It's important that this flag is kept up-to-date. It
is also used to skip visibility tests in sequential scans, which gives a
small performance gain on seqscans.
 		2008-12-03 13:05:22 +00:00
config configure check for docbook2man program, used in the new XML-based man 2008-11-26 11:26:54 +00:00
contrib Refactor crosstab() to build and return a tuplestore instead of using 2008-12-01 01:30:18 +00:00
doc Update key words table to 8.4 and SQL:2008. 2008-12-03 12:39:57 +00:00
src Introduce visibility map. The visibility map is a bitmap with one bit per 2008-12-03 13:05:22 +00:00
COPYRIGHT Update copyrights in source tree to 2008. 2008-01-01 19:46:01 +00:00
GNUmakefile.in Code coverage testing with gcov. Documentation is in the regression test 2008-09-05 12:11:18 +00:00
Makefile Remove remains of old depend target. 2007-01-20 17:16:17 +00:00
README Point to our download URL, rather than listing interface in the README 2008-05-06 22:02:12 +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 Change wildcard cerfificate mapping to be much simler - we now only match 2008-12-02 10:39:31 +00:00
configure.in Change wildcard cerfificate mapping to be much simler - we now only match 2008-12-02 10:39:31 +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, 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/.