Perfmon - Average latch wait time constantly high.

  • We are monitoring our SQL server with perfmon and one of the counter keeps consistently hight. The Average latch wait time (ms) is always at 1000 level, which means the average time it takes for a latch to be granted is about 1 second.

    Anybody know why is this counter constantly hight? How can I lower this?

    Thanks.

    James

  • I don't think you need to worry about this unless your other counters are giving rise to concern. It's not a counter i monitor.

    [font="Comic Sans MS"]The GrumpyOldDBA[/font]
    www.grumpyolddba.co.uk
    http://sqlblogcasts.com/blogs/grumpyolddba/

  • ...Latches are short term light weight synchronization objects.  Latches are not held for the duration of a transaction.  If high, check PERFMON for  memory pressure, disk bottlenecks. Did you perfrom benchmarking? You might want to write a query which will insert the result of Perfmon counters into the table, which you can analyze later.

  • How can I write a query which will insert the result of Perfmon counters into a table?

    Thanks.

  • well, basically output the counter you want to monitor to a CSV file format.

    Later files can then be imported into database PerfmonCounterLogs using DTS, for further analysis.You might want to do that on separate servers.

  • You can also get the SQL Server Perf Monitor counters from within SQL Server from the table sysperfinfo. 

    Check out BOL or execute

    select * from sysperfinfo

    where object_name = 'SQLServer:Latches'

    to get latch information. 

     

    Scott Thornburg

     

     

     

     

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