regaring wait events
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Thread: regaring wait events

  1. #1
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    regaring wait events

    Do we need to tune the wait event if total_timeouts column from v$system_event corresponding to that wait event is 0 or not increasing? Though the value in time_waited is high. The instance has been rebooted 3-4 days ago.
    lucky

  2. #2
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    it depends on the wait event.
    Pablo (Paul) Berzukov

    Author of Understanding Database Administration available at amazon and other bookstores.

    Disclaimer: Advice is provided to the best of my knowledge but no implicit or explicit warranties are provided. Since the advisor explicitly encourages testing any and all suggestions on a test non-production environment advisor should not held liable or responsible for any actions taken based on the given advice.

  3. #3
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    Any comments after having a look at this:
    Code:
                                                                         Avg
                                                         Total Wait    wait       Waits
    Event                                  Waits   Timeouts      Time (s)   (ms)     /txn
    ---------------------------- ------------ ---------- ---------- ------ --------
    db file sequential read           15,425           0        121           8         2.1
    direct path read                  190,330          0        109           1        25.5
    log file parallel write               13,674          0         34           2          1.8
    log file sync                           5,922          0         30           5          0.8
    Don't be lazy and use the code tags
    Last edited by davey23uk; 02-05-2010 at 11:07 AM.
    lucky

  4. #4
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    Quote Originally Posted by mahajanakhil198 View Post
    You can copy this on a textpad to have a better look of it.
    Why would I do that when you can post it properly with wrap code tags?
    Pablo (Paul) Berzukov

    Author of Understanding Database Administration available at amazon and other bookstores.

    Disclaimer: Advice is provided to the best of my knowledge but no implicit or explicit warranties are provided. Since the advisor explicitly encourages testing any and all suggestions on a test non-production environment advisor should not held liable or responsible for any actions taken based on the given advice.

  5. #5
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    The avg wait time (ms) for the top events are 8, 1, 2, 5. When these numbers are not very high, should I need to worry about the events? No.
    Did any user complaint about performance?

  6. #6
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    For an instance running for four days wait events suggest very little activity.
    "db file scatered read" doesn't even show on your top wait events.
    Is anybody complaining about performance? - if this is the case address the specific query user is complaining about.
    Pablo (Paul) Berzukov

    Author of Understanding Database Administration available at amazon and other bookstores.

    Disclaimer: Advice is provided to the best of my knowledge but no implicit or explicit warranties are provided. Since the advisor explicitly encourages testing any and all suggestions on a test non-production environment advisor should not held liable or responsible for any actions taken based on the given advice.

  7. #7
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    Yes, there are complaints. All I am supposed to do is to find something wrong if it is there. I checked out the memory structures, etc. Everything seemed to be alright. I had a doubt about wait events. So just felt like asking it. I would collect more data on Monday and then share it.


    And Yes, I wanted to represent the above output in the righteous manner but after so many attempts, I just couldn't find the right option. Thanks anyways!
    lucky

  8. #8
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    Quote Originally Posted by mahajanakhil198 View Post
    Yes, there are complaints.
    1- Identify the top five complains - start for the ones bothering management.
    2- Identify offending queries.
    3- Fine tune offending queries.
    4- Once offending queries are fixed document execution plan, cardinality of involved tables and, response time - tkprof-ed trace wouldn't hurt.
    5- Go to #1
    Pablo (Paul) Berzukov

    Author of Understanding Database Administration available at amazon and other bookstores.

    Disclaimer: Advice is provided to the best of my knowledge but no implicit or explicit warranties are provided. Since the advisor explicitly encourages testing any and all suggestions on a test non-production environment advisor should not held liable or responsible for any actions taken based on the given advice.

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