Re: Caching of Queries - Mailing list pgsql-performance

From Harald Fuchs
Subject Re: Caching of Queries
Date
Msg-id puzn3bg02g.fsf@srv.protecting.net
Whole thread Raw
In response to Caching of Queries  (Scott Kirkwood <scottakirkwood@gmail.com>)
List pgsql-performance
In article <1096261381.25688.741.camel@localhost.localdomain>,
Neil Conway <neilc@samurai.com> writes:

> I think the conclusion of past discussions about this feature is that
> it's a bad idea. Last I checked, MySQL has to clear the *entire* query
> cache when a single DML statement modifying the table in question is
> issued.

Nope, it deletes only queries using that table.

> Not to mention that the feature is broken for non-deterministic
> queries (like now(), ORDER BY random(), or nextval('some_seq'), and so
> on).

Queries containing now(), rand(), or similar functions aren't cached by MySQL.

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