From: Dan Nelson
Date: May 3 2006 9:29pm
Subject: Re: Q2. Is there anything could be done to speed up this query
List-Archive: http://lists.mysql.com/mysql/197584
Message-Id: <20060503212901.GD65700@dan.emsphone.com>
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In the last episode (May 03), Mikhail Berman said:
> Thank you, Chris 
> 
> But the table is indexed on the field you are referring to and the other
> one the query, which is evident from this:
> 
> >   KEY `prdadadx` (`price_data_date`),
> >   KEY `prdatidx` (`price_data_ticker`)

These are two separate keys, though, and your query is doing a GROUP BY
across both fields, so neither of those keys would be useful (mysql
would have to do a random record lookup for each row to fetch the other
field).  Try an index on (price_data_ticker, price_data_date).  Since
your query only references those fields, mysql should be able to return
your results just by scanning the index.

-- 
	Dan Nelson
	dnelson@stripped