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Re: slow queries and high % of wait I/O
Posted by: Rick James
Date: January 20, 2009 08:41PM

"the number of rows returned is usually 25. However, because of a bug in our application, at times we have around 200 or 300 and in some instances, it is even around 2000." ---
If the average is over about 100, then then this might account for all the elapsed time, namely doing disk seeks.

So, probably fixing that 'bug' will solve the whole issue. The disk will run warm, but acceptably.

I have focused on tallying the disk hits; you have perhaps accounted for enough to explain the delays. I can't think of anything else to look for.

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