Re: select from dblink very slow

From: Joe Conway <mail(at)joeconway(dot)com>
To: Jessica Richard <rjessil(at)yahoo(dot)com>
Cc: pgsql-admin(at)postgresql(dot)org
Subject: Re: select from dblink very slow
Date: 2007-05-18 16:31:11
Message-ID: 464DD4CF.5090807@joeconway.com
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Jessica Richard wrote:
> I need to joint select from table A in the current database A and dblink
> to table B in database B, the result coming from tableB in db B is very
> slow because I have to select all the rows from tableB from dblink then
> do "where" with table A in the current db....doing dblink this way is
> very very slow....
>
> Any idea on how to improve this?

About the only thing I can think of using dblink would be to use a
PL/pgSQL function to dynamically build and execute your query in such a
way that the WHERE clause is pushed to the remote query.

Someone else suggested dbi-link as an alternative -- I don't know for
sure, but suspect it will suffer from the same issue as dblink.

I also saw a suggestion of using different schemas instead of different
databases. This is the best solution if it is feasible.

Finally, I don't know much about it, but perhaps PL/proxy would make it
easier to push down your WHERE clause:
https://developer.skype.com/SkypeGarage/DbProjects/PlProxy

HTH,

Joe

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