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Heikki Linnakangas 81c4508196 Fix race condition between hot standby and restoring a full-page image.
There was a window in RestoreBackupBlock where a page would be zeroed out,
but not yet locked. If a backend pinned and locked the page in that window,
it saw the zeroed page instead of the old page or new page contents, which
could lead to missing rows in a result set, or errors.

To fix, replace RBM_ZERO with RBM_ZERO_AND_LOCK, which atomically pins,
zeroes, and locks the page, if it's not in the buffer cache already.

In stable branches, the old RBM_ZERO constant is renamed to RBM_DO_NOT_USE,
to avoid breaking any 3rd party extensions that might use RBM_ZERO. More
importantly, this avoids renumbering the other enum values, which would
cause even bigger confusion in extensions that use ReadBufferExtended, but
haven't been recompiled.

Backpatch to all supported versions; this has been racy since hot standby
was introduced.
2014-11-13 20:02:37 +02:00
config Add a basic atomic ops API abstracting away platform/architecture details. 2014-09-25 23:49:05 +02:00
contrib Move the guts of our Levenshtein implementation into core. 2014-11-13 12:33:26 -05:00
doc Tweak row-level locking documentation 2014-11-13 14:45:55 -03:00
src Fix race condition between hot standby and restoring a full-page image. 2014-11-13 20:02:37 +02:00
.dir-locals.el Update Emacs configuration 2013-08-13 20:08:44 -04:00
.gitattributes Add functions for dealing with PGP armor header lines to pgcrypto. 2014-10-01 16:03:39 +03:00
.gitignore Add *.pot to .gitignore 2013-10-19 10:56:52 -04:00
COPYRIGHT Update copyright for 2014 2014-01-07 16:05:30 -05:00
GNUmakefile.in Add TAP tests for client programs 2014-04-14 21:33:46 -04:00
HISTORY Improve text of stub HISTORY file. 2014-02-12 18:16:17 -05:00
Makefile Allow make check in PL directories 2011-02-15 06:52:12 +02:00
README Don't generate plain-text HISTORY and src/test/regress/README anymore. 2014-02-10 20:48:04 -05:00
README.git Don't generate plain-text HISTORY and src/test/regress/README anymore. 2014-02-10 20:48:04 -05:00
aclocal.m4 Remove cvs keywords from all files. 2010-09-20 22:08:53 +02:00
configure Add configure --enable-tap-tests option 2014-11-02 09:17:26 -05:00
configure.in Add configure --enable-tap-tests option 2014-11-02 09:17:26 -05:00

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.  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/.