It bring great effect in performance if federated engine can't use the cache.
If mysql intend to support it in the future? ----- Original Message ----- From: "Michael Loftis" <[EMAIL PROTECTED]> To: "wangxu" <[EMAIL PROTECTED]>; <mysql@lists.mysql.com> Sent: Thursday, August 03, 2006 1:27 AM Subject: Re: query cache about the federated engine > > > --On August 2, 2006 5:25:51 PM +0800 wangxu <[EMAIL PROTECTED]> wrote: > > > I have a problem about the performance of federated engine. The > > mysql5.0 reference manual says that the FEDERATED tables do not work with > > the query cache, aren't they? How about the query cache used by the > > federated engine in the mysql5.1? If the query cache cann't be used > > with the federated engine tables still, how to enhance the query > > performance against to the federated tables effectively? > > Well for one if the machine isn't on the same LAN you'll never have good DB > performance -- not sure if this is the case or not, just a helpful hint. > > For two, the reason why federated doesn't use the query cache is then you > have to somehow invalidate the remote cache(s) which would require some > form of protocol extension, either in the SQL or the over the wire protocol > so that the server with the federated table could ask if it could cache a > result, and the server that's serving to the federated client could inform > that server when it's cache isn't valid. > > > -- > MySQL General Mailing List > For list archives: http://lists.mysql.com/mysql > To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED] > >
