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imaginethat
Starting Member
5 Posts |
 Posted - 2007-09-20 : 21:10:53
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| I have a data mining app that does a series of select statements (no inserts). I'm noticing an odd occurance where if I start up 4 copies of the app on a quad core machine - sql takes full advantage of the 4 cores for a few minutes and then drops to 75% utilization - the other 25% is on the idle process. Two of the apps appear to be sharing a single proc of sql as each of their throughputs is cut by 50%. If I then start a 5th copy of the app, the machine is brought to full 100% utilization - two of the apps continue to appear to share a proc. SQL is set up to use all procs and I have even tried select the priority boost to no effect. Any ideas how to ensure full sql utilization with the same number of apps as cores?thanks, |
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rmiao
Master Smack Fu Yak Hacker
7266 Posts |
Posted - 2007-09-20 : 23:02:56
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| You have no control on that, and os tends to leave first processor idle for os and other processes. |
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imaginethat
Starting Member
5 Posts |
Posted - 2007-09-20 : 23:39:09
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| So the only answer is for my code to fetch the number of procs, then add one to that to ensure full utilization? I don't ever remember having this problem on sql 2000 on dual proc machines. |
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rmiao
Master Smack Fu Yak Hacker
7266 Posts |
Posted - 2007-09-21 : 00:07:18
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| You can try force it with maxdop hint. |
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Processor Utilization Question