[pgpool-general: 2703] Re: OTRS

Tatsuo Ishii ishii at postgresql.org
Fri Apr 4 16:13:20 JST 2014

> We're testing it with your suggested 0 backend weight in the slave. It
> working fine without load balancing mode.
> We would like to steer clear of the replication lag problems, that reason
> we're using synchronous replication with remote_write level settings.  But
> I see it is not enough.

No, it's not. PostgreSQL's synchronous replication does not guarantee
that on standby sever the log record has been replayed when master
returns a commit message. In short, there's always replication lag.

> Can You suggest us an useful solution?

As long as you use PostgreSQL's streaming replication, there's no
solution for replication delay. Possible solution would be:

1) modify your application so that it's ready for replication lag.

2) use pgpool's native replication mode.

> Thx,
> Csaba
> 2014-04-02 1:15 GMT+02:00 Tatsuo Ishii <ishii at postgresql.org>:
>> Humm.. there's no error messages in the pgpool log. Maybe the
>> replication lag? To make sure that if that is the cause of the
>> problem, you could set the slave's backend weight to 0 and restart
>> pgpool-II.
>> Best regards,
>> --
>> 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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