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Tom Lane fad153ec45 Rewrite the sinval messaging mechanism to reduce contention and avoid
unnecessary cache resets.  The major changes are:

* When the queue overflows, we only issue a cache reset to the specific
backend or backends that still haven't read the oldest message, rather
than resetting everyone as in the original coding.

* When we observe backend(s) falling well behind, we signal SIGUSR1
to only one backend, the one that is furthest behind and doesn't already
have a signal outstanding for it.  When it finishes catching up, it will
in turn signal SIGUSR1 to the next-furthest-back guy, if there is one that
is far enough behind to justify a signal.  The PMSIGNAL_WAKEN_CHILDREN
mechanism is removed.

* We don't attempt to clean out dead messages after every message-receipt
operation; rather, we do it on the insertion side, and only when the queue
fullness passes certain thresholds.

* Split SInvalLock into SInvalReadLock and SInvalWriteLock so that readers
don't block writers nor vice versa (except during the infrequent queue
cleanout operations).

* Transfer multiple sinval messages for each acquisition of a read or
write lock.
2008-06-19 21:32:56 +00:00
config Require bind_textdomain_codeset() not just gettext() to enable NLS support. 2008-05-27 22:18:04 +00:00
contrib Improve our #include situation by moving pointer types away from the 2008-06-19 00:46:06 +00:00
doc Add URL for: 2008-06-19 01:15:48 +00:00
src Rewrite the sinval messaging mechanism to reduce contention and avoid 2008-06-19 21:32:56 +00:00
aclocal.m4 Add new auto-detection of thread flags. 2004-04-23 18:15:55 +00:00
configure Require bind_textdomain_codeset() not just gettext() to enable NLS support. 2008-05-27 22:18:04 +00:00
configure.in Adjust -Wl,--asneeded test to avoid using the switch if it breaks 2008-05-20 03:30:22 +00:00
COPYRIGHT Update copyrights in source tree to 2008. 2008-01-01 19:46:01 +00:00
GNUmakefile.in Catch all errors in for and while loops in makefiles. Don't ignore any 2008-03-18 16:24:50 +00:00
Makefile Remove remains of old depend target. 2007-01-20 17:16:17 +00:00
README Point to our download URL, rather than listing interface in the README 2008-05-06 22:02:12 +00:00
README.CVS Some further editorializing on README.CVS. 2004-03-28 06:09:08 +00:00

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.  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/.