[pgpool-general: 1778] Re: replication method

Tatsuo Ishii ishii at postgresql.org
Mon May 27 17:56:03 JST 2013

> Does anyone have any recommendations as to whether to use Pgpool
> replication or Postgres streaming replication? We need to have a
> system in place where a db server can fail without any users being
> affected by the fail. The application has around an 80:20 split
> read/write. We will be using Pgpool for load balancing etc. in either
> case.
> Thanks
> Garry

Hi Garry,

The chpice depends on your applications.

Streaming replication advantages:
- Write query is faster
- Less SQL restrictions
- SELECT load balances even in an explicit transaction

Streaming replication disadvantages:
- Asynchronous replication (even with PostgreSQL "synchronous"
  replication, it's actually an asynchronous replicatin). So your
  application should aware that SELECT may retrieve outdated data.
- Failover/online script tends to be complicated, especially if you
  plan to have more than 2 standbys

pgpool replication advantages:
- True synchronous replication
- Failover/online script is simple

pgpool replication disadvantages:
- Write query is slower
- More SQL restrictions
- SELECT does not load balances in an explicit transaction
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
Japanese: http://www.sraoss.co.jp

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