Re: [COMMITTERS] pgsql: Remove replicaiton FAQ item.

Martha Stewart called it a Good Thing when pgman(at)candle(dot)pha(dot)pa(dot)us (Bruce Momjian) wrote:
> Yep, big mistake my removing the replication FAQ item. I have re-added a
> new one:
>
> 4.21) What replication solutions are available?
>
> Though "replication" is a single term, there are two major replication
> technologies. Multi-master replication allows read/write queries to be
> sent to multiple replicated computers. Using this capability has a
> serious performance impact. Pgcluster is the most popular such solution
> available for PostgreSQL. Master-slave replication allows a single
> master to receive read/write queries, with slaves able to accept only
> read/SELECT queries. The most popular master-slave PostgreSQL
> replication solution is Slony. There are also commercial and
> hardware-based replication solutions available.

A suggestion for rewording:

Though "replication" is a single term, there are a number of
approaches and technologies to handle it, and thus, for different
purposes, a number of replication systems are available.

Master/slave replication allows a single master to receive read/write
queries, where slaves can only accept read/SELECT queries. The most
popular freely available master-slave PostgreSQL replication solution
is Slony-I.

Multi-master replication allows read/write queries to be sent to
multiple replicated computers. Using this capability generaly has a
fairly severe impact on performance due to the need to synchronize
changes between servers. Pgcluster is the most popular such solution
freely available for PostgreSQL.

There are also commercial and hardware-based replication solutions
available supporting a variety of replication models.
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