MySQL TEXT field performance

Posted by Jonathon on Stack Overflow See other posts from Stack Overflow or by Jonathon
Published on 2010-05-21T16:38:00Z Indexed on 2010/05/21 16:40 UTC
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mysql

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query

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optimization

I have several TEXT and/or MEDIUMTEXT fields in each of our 1000 MySQL tables. I now know that TEXT fields are written to disk rather than in memory when queried. Is that also true even if that field is not called in the query? For example, if I have a table (tbExam) with 2 fields (id int(11) and comment text) and I run SELECT id FROM tbExam, does MySQL still have to write that to disk before returning results or will it run that query in memory?

I am trying to figure out if I need to reconfigure our actual db tables to switch to varchar(xxxx) or keep the text fields and reconfigure the queries.

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