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Tom Lane ee0d06c0b9 Fix rare startup failure induced by MVCC-catalog-scans patch.
While a new backend nominally participates in sinval signaling starting
from the SharedInvalBackendInit call near the top of InitPostgres, it
cannot recognize sinval messages for unshared catalogs of its database
until it has set up MyDatabaseId.  This is not problematic for the catcache
or relcache, which by definition won't have loaded any data from or about
such catalogs before that point.  However, commit 568d4138c6
introduced a mechanism for re-using MVCC snapshots for catalog scans, and
made invalidation of those depend on recognizing relevant sinval messages.
So it's possible to establish a catalog snapshot to read pg_authid and
pg_database, then before we set MyDatabaseId, receive sinval messages that
should result in invalidating that snapshot --- but do not, because we
don't realize they are for our database.  This mechanism explains the
intermittent buildfarm failures we've seen since commit 31eae6028e.
That commit was not itself at fault, but it introduced a new regression
test that does reconnections concurrently with the "vacuum full pg_am"
command in vacuum.sql.  This allowed the pre-existing error to be exposed,
given just the right timing, because we'd fail to update our information
about how to access pg_am.  In principle any VACUUM FULL on a system
catalog could have created a similar hazard for concurrent incoming
connections.  Perhaps there are more subtle failure cases as well.

To fix, force invalidation of the catalog snapshot as soon as we've
set MyDatabaseId.

Back-patch to 9.4 where the error was introduced.
2015-04-03 00:07:29 -04:00
config Silence Bison deprecation warnings 2014-06-03 22:36:35 -04:00
contrib Remove spurious semicolons. 2015-03-31 15:13:35 +03:00
doc psql: fix \connect with URIs and conninfo strings 2015-04-01 20:00:07 -03:00
src Fix rare startup failure induced by MVCC-catalog-scans patch. 2015-04-03 00:07:29 -04:00
.dir-locals.el Update Emacs configuration 2013-08-13 20:08:44 -04:00
.gitattributes gitattributes: Ignore time zone data files for whitespace checks 2014-07-22 00:12:28 -04:00
.gitignore Add *.pot to .gitignore 2013-10-19 10:56:52 -04:00
aclocal.m4 Remove cvs keywords from all files. 2010-09-20 22:08:53 +02:00
configure src/port/dirmod.c needs to be built on Cygwin too. 2015-03-15 14:14:24 -04:00
configure.in src/port/dirmod.c needs to be built on Cygwin too. 2015-03-15 14:14:24 -04:00
COPYRIGHT Update copyright for 2015 2015-01-06 11:43:46 -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

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/.