Re: How to reduce impact of a query.

Scott Marlowe wrote:
> The problem is most likely you're I/O bound.  If one query is hitting
> a table it can pull in data (sequentially) at 40 to 80 megabytes per
> second.  Since most of your queries are small, they don't run into
> each other a lot, so to speak. As soon as your big reporting query
> hits it's likely hitting the drives much longer and getting in the way
> of all the other queries.
>
>
Thanks for the input Scott. You are correct - I am IO bound, but only
for the query described. 99% of the time, my IO runs at 3% or less, even
during peak times, only this one query, which happens approximately 10
times a day grinds the system to a halt.

I am considering running this query in the background every couple of
minutes or so to force the tables/indexes into cache. Once the tables
are cached the query runs very quickly and there is no significant IO
impact.This is a bodge but hopefully should work.