postgresql

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Tom Lane 45f9d08684 Fix race condition with unprotected use of a latch pointer variable. Commit `597a87ccc` introduced a latch pointer variable to replace use of a long-lived shared latch in the shared WalRcvData structure. This was not well thought out, because there are now hazards of the pointer variable changing while it's being inspected by another process. This could obviously lead to a core dump in code like if (WalRcv->latch) SetLatch(WalRcv->latch); and there's a more remote risk of a torn read, if we have any platforms where reading/writing a pointer is not atomic. An actual problem would occur only if the walreceiver process exits (gracefully) while the startup process is trying to signal it, but that seems well within the realm of possibility. To fix, treat the pointer variable (not the referenced latch) as being protected by the WalRcv->mutex spinlock. There remains a race condition that we could apply SetLatch to a process latch that no longer belongs to the walreceiver, but I believe that's harmless: at worst it'd cause an extra wakeup of the next process to use that PGPROC structure. Back-patch to v10 where the faulty code was added. Discussion: https://postgr.es/m/22735.1507048202@sss.pgh.pa.us		2017-10-03 14:00:56 -04:00
config	Extend & revamp pg_bswap.h infrastructure.	2017-09-29 17:24:39 -07:00
contrib	Replace most usages of ntoh[ls] and hton[sl] with pg_bswap.h.	2017-10-01 15:36:14 -07:00
doc	Expand collation documentation	2017-10-02 11:51:45 -04:00
src	Fix race condition with unprotected use of a latch pointer variable.	2017-10-03 14:00:56 -04:00
.dir-locals.el	emacs: Set indent-tabs-mode in perl-mode	2015-04-12 23:53:23 -04:00
.gitattributes	Remove contrib/tsearch2.	2017-02-13 11:06:11 -05:00
.gitignore	Add lcov --initial	2017-09-29 08:54:34 -04:00
aclocal.m4	Make configure check for IPC::Run when --enable-tap-tests is specified.	2017-06-15 15:56:12 -04:00
configure	Extend & revamp pg_bswap.h infrastructure.	2017-09-29 17:24:39 -07:00
configure.in	Extend & revamp pg_bswap.h infrastructure.	2017-09-29 17:24:39 -07:00
COPYRIGHT	Update copyright for 2017	2017-01-03 12:37:53 -05:00
GNUmakefile.in	Have "make coverage" recurse into contrib as well	2016-09-05 18:44:36 -03:00
HISTORY	Change documentation references to PG website to use https: not http:	2017-05-20 21:50:47 -04:00
Makefile	Prevent passing down MAKELEVEL/MAKEFLAGS from non-GNU make to GNU make.	2017-08-09 12:05:53 -04:00
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

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:

	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/.