Add mention of shared-memory/disk for multi-master clustering.

This commit is contained in:
Bruce Momjian 2006-11-22 03:44:52 +00:00
parent 617f123f06
commit ffa0e8f0cd

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@ -1,4 +1,4 @@
<!-- $PostgreSQL: pgsql/doc/src/sgml/high-availability.sgml,v 1.8 2006/11/21 22:48:33 momjian Exp $ -->
<!-- $PostgreSQL: pgsql/doc/src/sgml/high-availability.sgml,v 1.9 2006/11/22 03:44:52 momjian Exp $ -->
<chapter id="high-availability">
<title>High Availability and Load Balancing</title>
@ -193,11 +193,13 @@ protocol to make nodes agree on a serializable transactional order.
other server before each transaction commits. Heavy write
activity can cause excessive locking, leading to poor performance.
In fact, write performance is often worse than that of a single
server. Read requests can be sent to any server. Clustering
is best for mostly read workloads, though its big advantage
is that any server can accept write requests &mdash; there is
no need to partition workloads between master and slave servers,
and because the data changes are sent from one server to another,
server. Read requests can be sent to any server. Some
implementations use cluster-wide shared memory or shared disk
to reduce the communication overhead. Clustering is best for
mostly read workloads, though its big advantage is that any
server can accept write requests &mdash; there is no need to
partition workloads between master and slave servers, and
because the data changes are sent from one server to another,
there is no problem with non-deterministic functions like
<function>random()</>.
</para>