Latch Waits and SQL Server Performance

• sswords

  SSCrazy Eights

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  May 13, 2003 at 7:26 am

  #64218

  Greetings All,

  I have an older test server where users are complaining of very poor peformance running a SQL Server based app. I've added RAM, defraged the disks, replaced the NIC card, re-indexed the entire DB to no avail. The event logs don't reveal any problems. The only thing I can find that's indicative of any problem is that SQL Check shows a very high latch wait time for this server which is > 560 after a restart and can go as high as 1000 ms.

  I have production servers with many times more users running at higher processor utilization and the latch waits typically are less than half of this value. I haven't been able to find much on the web or BOL regarding latch waits except that it's usually some function of I/O that causes excessive wait times. So, I really don't know what else to check at this point. Or am I maybe barking up the wrong tree looking at the latch waits?

  FYI - the server is an older Compaq Proliant 2x200 mHz proc with over 1 G of RAM, Raid 1 (OS, Logs) Raid 5 (Data drives) running Windows NT 4 SP 6a, SQL Server 7.0 SP3. Page file is 1.3 G spread across the 3 logical drives. Any info or thoughts are appreciated.

  My hovercraft is full of eels.

• well0549

  SSCrazy

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  May 14, 2003 at 4:46 am

  #457081

  Try performance monitor.

  Have a look at Physical disk.....

  Disk QUE length.....

  Don't forget DIskperf -Y.....

• grahamc

  SSCertifiable

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  January 3, 2006 at 4:07 am

  #612362

  Any info on this, as I am having similar problems?

  Thanks,

  Graham