Base de données relationnelle
Find a file
Alvaro Herrera 469fa9ad6d Change some bogus PageGetLSN calls to BufferGetLSNAtomic
As src/backend/access/transam/README says, PageGetLSN may only be called
by processes holding either exclusive lock on buffer, or a shared lock
on buffer plus buffer header lock.  Therefore any place that only holds
a shared buffer lock must use BufferGetLSNAtomic instead of PageGetLSN,
which internally obtains buffer header lock prior to reading the LSN.

A few callsites failed to comply with this rule.  This was detected by
running all tests under a new (not committed) assertion that verifies
PageGetLSN locking contract.  All but one of the callsites that failed
the assertion are fixed by this patch.  Remaining callsites were
inspected manually and determined not to need any change.

The exception (unfixed callsite) is in TestForOldSnapshot, which only
has a Page argument, making it impossible to access the corresponding
Buffer from it.  Fixing that seems a much larger patch that will have to
be done separately; and that's just as well, since it was only
introduced in 9.6 and other bugs are much older.

Some of these bugs are ancient; backpatch all the way back to 9.3.

Authors: Jacob Champion, Asim Praveen, Ashwin Agrawal
Reviewed-by: Michaël Paquier
Discussion: https://postgr.es/m/CABAq_6GXgQDVu3u12mK9O5Xt5abBZWQ0V40LZCE+oUf95XyNFg@mail.gmail.com
2018-01-09 17:07:00 -03:00
config MSVC: Test whether 32-bit Perl needs -D_USE_32BIT_TIME_T. 2017-12-08 18:14:08 -08:00
contrib Avoid formally-undefined use of memcpy() in hstoreUniquePairs(). 2017-11-25 14:42:46 -05:00
doc Update copyright for 2018 2018-01-02 23:30:12 -05:00
src Change some bogus PageGetLSN calls to BufferGetLSNAtomic 2018-01-09 17:07:00 -03:00
.gitignore Add /config.cache to .gitignore in back branches 2017-02-25 13:04:22 -05:00
aclocal.m4 Remove cvs keywords from all files. 2010-09-20 22:08:53 +02:00
configure Support linking with MinGW-built Perl. 2017-11-23 20:32:01 -08:00
configure.in Revert "Allow --with-bonjour to work with non-macOS implementations of Bonjour." 2017-11-09 11:00:36 -05:00
COPYRIGHT Update copyright for 2018 2018-01-02 23:30:12 -05:00
GNUmakefile.in Don't generate plain-text HISTORY and src/test/regress/README anymore. 2014-02-10 20:48:12 -05:00
HISTORY Change documentation references to PG website to use https: not http: 2017-05-20 21:50:47 -04:00
Makefile Fix non-GNU makefiles for AIX make. 2017-11-30 00:57:32 -08:00
README Change documentation references to PG website to use https: not http: 2017-05-20 21:50:47 -04:00
README.git Change documentation references to PG website to use https: not http: 2017-05-20 21:50:47 -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, many of which are listed here:

	https://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
https://www.postgresql.org/download/.  For more information look at our
web site located at https://www.postgresql.org/.