From: Dan Nelson
Date: October 3 2006 9:53pm
Subject: Re: creating indexes on a  table already containing data
List-Archive: http://lists.mysql.com/mysql/202298
Message-Id: <20061003215323.GB54791@dan.emsphone.com>
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In the last episode (Oct 03), Angelo Zanetti said:
> I've got a database that has a few thousand rows, I've noticed that
> some of the search queries (especially the large ones) are taking
> some time. Im looking at adding indexes to my tables in order to
> speed up the data retrieval.
> 
> My question is as follows: At this point in time if I add the indexes
> to the various tables should I see immediate results in the query
> times or do I have to wait for new information to enter the database
> (only new data gets indexed?)
>
> When does the data actually get indexed? Is it when its inserted or
> continually when regards are inserted or updated in the database?

When you add an index, Mysql builds a complete index of your table
immediately.  For a few thousand rows it should take under a minute. 
The index will automatically be updated as you insert rows or change
existing ones.

-- 
	Dan Nelson
	dnelson@stripped