postgresql

mirror of https://git.postgresql.org/git/postgresql.git synced 2024-08-27 11:47:19 +02:00

History

Tom Lane 3a246cc285 Arrange to preallocate all required space for the buffer and FSM hash tables in shared memory. This ensures that overflow of the lock table creates no long-lasting problems. Per discussion with Merlin Moncure.		2004-09-28 20:46:37 +00:00
..
ipc.c	Pgindent run for 8.0.	2004-08-29 05:07:03 +00:00
ipci.c	Pgindent run for 8.0.	2004-08-29 05:07:03 +00:00
Makefile	$Header: -> $PostgreSQL Changes ...	2003-11-29 19:52:15 +00:00
pmsignal.c	Pgindent run for 8.0.	2004-08-29 05:07:03 +00:00
README	$Header: -> $PostgreSQL Changes ...	2003-11-29 19:52:15 +00:00
shmem.c	Arrange to preallocate all required space for the buffer and FSM hash	2004-09-28 20:46:37 +00:00
shmqueue.c	Update copyright to 2004.	2004-08-29 04:13:13 +00:00
sinval.c	RecentXmin is too recent to use as the cutoff point for accessing	2004-09-16 18:35:23 +00:00
sinvaladt.c	Pgindent run for 8.0.	2004-08-29 05:07:03 +00:00

README

$PostgreSQL: pgsql/src/backend/storage/ipc/README,v 1.4 2003/11/29 19:51:56 pgsql Exp $
Mon Jul 18 11:09:22 PDT 1988  W.KLAS

Cache invalidation synchronization routines:
===========================================

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.