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Re: Selects are slow when blob field?
Posted by: Harrison Fisk
Date: November 26, 2004 10:41AM

Hi,

I was referring to the statement you made:

"My example is contrived because in reality all queries need the blob data, so moving the blob to a join table would not bring me any benefits."

I told you how you would split up the tables in order to increase speed for the first query you said, but you said you couldn't do that because you always retrieve blobs. So I told you why always retrieving the blob was going to be slow.

As far as why the first was one was slow, MyISAM always reads the entire row, so it is reading the blob even though it technically doesn't need it. Splitting the tables to avoid this is a fairly standard practice.

Harrison Fisk, Trainer and Consultant
MySQL AB, www.mysql.com

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