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From: Harrison Fisk (Harrison.FiskSun.COM)
Date: Wed Dec 09 2009 - 13:06:30 CST
On Dec 9, 2009, at 11:22 AM, Johan De Meersman wrote:
> Posted this before, but beware: federated tables do NOT use indices.
> select is a full table scan, and if you're talking about a logging
> that could become very expensive very fast.
This is not entirely true. If you define an index on the local
federated table, and it makes sense to use it, then a remote WHERE
clause will be passed through and hence use the remote index. Not all
types of index accesses can be passed through such as this, however
for a single row lookup on a primary key, it should be fine.
It is still not as fast as local access, but it's not as bad as always
doing a full table scan remotely.
> On Wed, Dec 9, 2009 at 4:13 PM, Neil Aggarwal
>>> Is this possible to do? To make a connection, inside the
>>> stored procedure
>>> to a completely different machine and access the mysql there?
>> The only way I know to access tables from different servers
>> from a single connection is federated tables:
>> Once you do that, you are accessing it like a local table.
>> I hope this helps.
Harrison C. Fisk, MySQL Staff Support Engineer
MySQL Sun Microsystems, Inc., http://www.sun.com/mysql/
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