From: Wm Mussatto
Date: July 20 2007 8:41pm
Subject: Re: MySQL slow when altering tables.
List-Archive: http://lists.mysql.com/mysql/208173
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On Fri, July 20, 2007 12:32, Andrew Rosolino said:
>
> Whenever I alter a mysql table like add a new field it gets really slow
> and
> all other processes lag.
> Is there a memory variable I can adjust for this?
> --
> View this message in context:
Without more information it might be hard to answer.  A general though:
Alter Table causes the entire table to be re-created in its new form and
then the old one deleted and the new one renamed.  For a large table that
is a significant bit of work (cpu, disk  and memory).  It might help if
you could give the size of the table and what the alter involved (for
example generating a new index would take even more time).

------
William R. Mussatto
Systems Engineer
http://www.csz.com
909-920-9154