Re: PostgreSQL clustering VS MySQL clustering

From: "Joshua D(dot) Drake" <jd(at)commandprompt(dot)com>
To: Matt Clark <matt(at)ymogen(dot)net>
Cc: Tatsuo Ishii <t-ishii(at)sra(dot)co(dot)jp>, pgsql-performance(at)postgresql(dot)org
Subject: Re: PostgreSQL clustering VS MySQL clustering
Date: 2005-01-21 15:40:57
Message-ID: 41F12289.1070104@commandprompt.com
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Matt Clark wrote:

> Presumably it can't _ever_ know without being explicitly told, because
> even for a plain SELECT there might be triggers involved that update
> tables, or it might be a select of a stored proc, etc. So in the
> general case, you can't assume that a select doesn't cause an update,
> and you can't be sure that the table list in an update is a complete
> list of the tables that might be updated.

Uhmmm no :) There is no such thing as a select trigger. The closest you
would get
is a function that is called via select which could be detected by
making sure
you are prepending with a BEGIN or START Transaction. Thus yes pgPool
can be made
to do this.

Sincerely,

Joshua D. Drake

>
>
>
> Tatsuo Ishii wrote:
>
>> Can I ask a question?
>>
>> Suppose table A gets updated on the master at time 00:00. Until 00:03
>> pgpool needs to send all queries regarding A to the master only. My
>> question is, how can pgpool know a query is related to A?
>> --
>> Tatsuo Ishii
>>
>>
>>
>
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