How to query to find Parallelism query history?

  • On my production box CXPACKET is High around 65% and server has been up for almost 3 months. My question is instead of running Profiler while query is (are) running from Application. What's the best way to find history of queries which ran parallel. If there any, should I run on Production during on hours?

    One last thing, should I reboot Prod server once 3 months? I read different recommendations.

    Thank you

  • Jonathan Kehayias has a query in this post, http://www.sqlskills.com/blogs/jonathan/tuning-cost-threshold-for-parallelism-from-the-plan-cache/, that shows parallel queries in the cache. I think you can run it against production, but I'm cautious and would run it in off-hours, not when the server is at its busiest.

    I don't know why you'd need to reboot the server every 3 months. The only reason I'd be rebooting is for patching (windows, sql, application) that requires a reboot. I think if you have to reboot for any other reason you have other problems.

  • Thanks Mr. Jack

  • As a first try, look at that instance, "Reports", "Standard Reports", "Total CPU Time" and "Average CPU Time".

    On rebooting, it depends. If you have a lot of non-SQL stuff running on the box, reboots can help, since RAM may get fragmented or lost (memory leak). Also, SQL itself at times must allocate contiguous RAM, and too much RAM fragmentation interferes with/can delay that.

    SQL DBA,SQL Server MVP(07, 08, 09) "It's a dog-eat-dog world, and I'm wearing Milk-Bone underwear." "Norm", on "Cheers". Also from "Cheers", from "Carla": "You need to know 3 things about Tortelli men: Tortelli men draw women like flies; Tortelli men treat women like flies; Tortelli men's brains are in their flies".

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