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Tom Lane 0f5d208253 Avoid problems with OID wraparound during WAL replay.
Fix a longstanding thinko in replay of NEXTOID and checkpoint records: we
tried to advance nextOid only if it was behind the value in the WAL record,
but the comparison would draw the wrong conclusion if OID wraparound had
occurred since the previous value.  Better to just unconditionally assign
the new value, since OID assignment shouldn't be happening during replay
anyway.

The consequences of a failure to update nextOid would be pretty minimal,
since we have long had the code set up to obtain another OID and try again
if the generated value is already in use.  But in the worst case there
could be significant performance glitches while such loops iterate through
many already-used OIDs before finding a free one.

The odds of a wraparound happening during WAL replay would be small in a
crash-recovery scenario, and the length of any ensuing OID-assignment stall
quite limited anyway.  But neither of these statements hold true for a
replication slave that follows a WAL stream for a long period; its behavior
upon going live could be almost unboundedly bad.  Hence it seems worth
back-patching this fix into all supported branches.

Already fixed in HEAD in commit c6d76d7c82.
2012-02-06 13:15:04 -05:00
config Replace obsolete AC_LANG_FUNC_LINK_TRY autoconf macro. 2011-08-29 19:52:07 -04:00
contrib Fix error detection in contrib/pgcrypto's encrypt_iv() and decrypt_iv(). 2012-01-27 23:10:02 -05:00
doc Stamp 8.3.17. 2011-12-01 16:55:48 -05:00
src Avoid problems with OID wraparound during WAL replay. 2012-02-06 13:15:04 -05:00
.gitignore Convert cvsignore to gitignore, and add .gitignore for build targets. 2010-09-22 12:57:12 +02:00
aclocal.m4 Add new auto-detection of thread flags. 2004-04-23 18:15:55 +00:00
configure Use __sync_lock_test_and_set() for spinlocks on ARM, if available. 2012-01-07 15:39:16 -05:00
configure.in Use __sync_lock_test_and_set() for spinlocks on ARM, if available. 2012-01-07 15:39:16 -05:00
COPYRIGHT Update copyrights in source tree to 2008. 2008-01-01 19:46:01 +00:00
GNUmakefile.in Back-patch creation of tar.bz2 tarball during "make dist". 2011-07-03 16:40:34 -04:00
Makefile Remove remains of old depend target. 2007-01-20 17:16:17 +00:00
README Update libpqxx URL in top-level README, per Gurjeet Singh. 2008-03-05 17:04:42 +00:00
README.git Back-patch replacement of README.CVS with README.git. 2010-09-21 14:43:11 -04:00

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://pqxx.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, incomplete list is below:

PL/pgSQL - included in PostgreSQL source distribution
PL/Perl - included in PostgreSQL source distribution
PL/PHP - http://projects.commandprompt.com/projects/public/plphp
PL/Python - included in PostgreSQL source distribution
PL/Java - http://pgfoundry.org/projects/pljava/
PL/Tcl - included in PostgreSQL source distribution

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/.