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grigdog
Starting Member
2 Posts |
 Posted - 2011-05-18 : 15:44:32
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| We are experiencing database performance issues which I think is related to a high number of waiting tasks. The number is between 20 and 120 and then briefly spikes into the 100,000, I've seen it as high as almost 400,000. The wait types I'm seeing in high number are LCK_M_U and CXPACKET. Any ideas? |
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tkizer
Almighty SQL Goddess
38200 Posts |
Posted - 2011-05-18 : 17:41:54
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| Run Paul's wait stats query (http://www.sqlskills.com/BLOGS/PAUL/post/Wait-statistics-or-please-tell-me-where-it-hurts.aspx) and let us know the top few worse waits. If it's CXPACKET, we'll you've got a parallel processing issue that needs to be addressed. What's your maxdop set to? What does the missing indexes report show (http://sqlserverpedia.com/wiki/Find_Missing_Indexes)?Tara KizerMicrosoft MVP for Windows Server System - SQL Serverhttp://weblogs.sqlteam.com/tarad/Subscribe to my blog |
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grigdog
Starting Member
2 Posts |
Posted - 2011-05-19 : 09:33:27
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| I think I found the problem. Just about every proc accepts sessionid guid and then uses that to look up userid. The query was using LIKE on the guid instead of =. We'll be releasing the fix today. Sound plausible that the LIKE keyword was causing the issue on a high-traffic database? |
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robvolk
Most Valuable Yak
15732 Posts |
Posted - 2011-05-19 : 09:40:49
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| Could be, depends how the LIKE was written. |
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tkizer
Almighty SQL Goddess
38200 Posts |
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Waiting Tasks Spike
Tara Kizer