postgresql/src/backend/storage/ipc
Tom Lane d1e027221d Replace the pg_listener-based LISTEN/NOTIFY mechanism with an in-memory queue.
In addition, add support for a "payload" string to be passed along with
each notify event.

This implementation should be significantly more efficient than the old one,
and is also more compatible with Hot Standby usage.  There is not yet any
facility for HS slaves to receive notifications generated on the master,
although such a thing is possible in future.

Joachim Wieland, reviewed by Jeff Davis; also hacked on by me.
2010-02-16 22:34:57 +00:00
..
ipc.c Update copyright for the year 2010. 2010-01-02 16:58:17 +00:00
ipci.c Replace the pg_listener-based LISTEN/NOTIFY mechanism with an in-memory queue. 2010-02-16 22:34:57 +00:00
Makefile Allow read only connections during recovery, known as Hot Standby. 2009-12-19 01:32:45 +00:00
pmsignal.c Introduce Streaming Replication. 2010-01-15 09:19:10 +00:00
procarray.c In HS, Startup process sets SIGALRM when waiting for buffer pin. If 2010-01-23 16:37:12 +00:00
procsignal.c Re-enable max_standby_delay = -1 using deadlock detection on startup 2010-02-13 01:32:20 +00:00
README Make source code READMEs more consistent. Add CVS tags to all README files. 2008-03-20 17:55:15 +00:00
shmem.c Update copyright for the year 2010. 2010-01-02 16:58:17 +00:00
shmqueue.c Update copyright for the year 2010. 2010-01-02 16:58:17 +00:00
sinval.c Update copyright for the year 2010. 2010-01-02 16:58:17 +00:00
sinvaladt.c Update copyright for the year 2010. 2010-01-02 16:58:17 +00:00
standby.c Improvements to ps message of startup process during Hot Standby. 2010-02-13 16:29:38 +00:00

$PostgreSQL: pgsql/src/backend/storage/ipc/README,v 1.5 2008/03/20 17:55:15 momjian Exp $

Cache Invalidation Synchronization Routines
===========================================

Mon Jul 18 11:09:22 PDT 1988  W.KLAS

The cache synchronization is done using a message queue. Every
backend can register a message which then has to be read by
all backends. A message read by all backends is removed from the 
queue automatically. If a message has been lost because the buffer
was full, all backends that haven't read this message will be
told that they have to reset their cache state. This is done
at the time when they try to read the message queue.

The message queue is implemented as a shared buffer segment. Actually,
the queue is a circle to allow fast inserting, reading (invalidate data) and
maintaining the buffer.