“SELECT COUNT(*)” is slow, even with where clause

Question

I\'m trying to figure out how to optimize a very slow query in MySQL (I didn\'t design this):

SELECT COUNT(*) FROM change_event me WHERE change_event_id >         


        

Answer 1

Check to see how fragmented your indexes are. At my company we have a nightly import process that trashes our indexes and over time it can have a profound impact on data access speeds. For example we had a SQL procedure that took 2 hours to run one day after de-fragmenting the indexes it took 3 minutes. we use SQL Server 2005 ill look for a script that can check this on MySQL.

Update: Check out this link: http://dev.mysql.com/doc/refman/5.0/en/innodb-file-defragmenting.html