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<chapter id="high-availability">

<title>High Availability, Load Balancing, and Replication</title>

<para>

Many of the above solutions allow multiple servers to handle multiple

queries, but none allow a single query to use multiple servers to

complete faster. This allows multiple servers to work concurrently

on a single query.This is usually accomplished by splitting the

data among servers and having each server execute its part of the

query and return results to a central server where they are combined

and returned to the user. <productname>Pgpool-II</> has this

capability. Also, this can be implemented using the

complete faster. Thissolutionallows multiple servers to work

concurrentlyon a single query.It is usually accomplished by

splitting thedata among servers and having each server execute its

part of thequery and return results to a central server where they

are combinedand returned to the user. <productname>Pgpool-II</>

has thiscapability. Also, this can be implemented using the

<productname>PL/Proxy</> toolset.

</para>