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5 Replies Latest reply: Jan 9, 2011 8:35 AM by Insaponata RSS

high virtual circuit wait event

Insaponata Newbie
Currently Being Moderated
Hi,
in my 11g Enterprise Edition Database I have a problem with some sessions that are almost always in virtual circuit wait event. What is this wait event and how can I troubleshoot it?

IMPORTANT: I'm not using XDB or APEX

Edited by: Insaponata on Jan 9, 2011 8:00 AM
  • 1. Re: high virtual circuit wait event
    sb92075 Guru
    Currently Being Moderated
    I have a problem with some sessions that are almost always in virtual circuit wait event.
    Why is this considered a problem?

    post formatted SQL & results
  • 2. Re: high virtual circuit wait event
    Insaponata Newbie
    Currently Being Moderated
    From awr report based on the last our of work I see:

    Top 5 Timed Foreground Events

    Event     Waits     Time(s)     Avg wait (ms)     % DB time     Wait Class
    virtual circuit wait     95,038     16,056     169     263.91     Network
    DB CPU          305          5.02     
    SQL*Net message from dblink     42,432     48     1     0.79     Network
    db file sequential read     21,990     48     2     0.78     User I/O
    db file scattered read     26,021     36     1     0.59     User I/O


    Do you think that this situation is normal? If no, how can I troubleshoot?
  • 3. Re: high virtual circuit wait event
    sb92075 Guru
    Currently Being Moderated
    posted results NOT formated & difficult to read

    It appears system/DB is/was most idle.
    Over what period of time was AWR snapshot taken/reported?
    Do you think that this situation is normal?
    Yes, normal.

    Top wait event
    In EVERY Top Wait Event list, one wait event will ALWAYS be on top as #1; by definition of the list.
    Simply because any item, even #1, appears on this list does not mean this is a problem & needs to be fixed.
    If the Top Wait Event accounts for only 5 seconds out of a 1 hour sample,
    then reducing it to ZERO won't measurably improve overall application performance.
  • 4. Re: high virtual circuit wait event
    Insaponata Newbie
    Currently Being Moderated
    Sorry, but I don't know how to format text in this forum.

    It's the first time in my life I see "virtual circuit" wait event, and I'm not able to find any significant information from support site. Do you know what is this event?
  • 5. Re: high virtual circuit wait event
    sb92075 Guru
    Currently Being Moderated
    Sorry, but I don't know how to format text in this forum.
    http://wikis.sun.com/display/Forums/Forums+FAQ
    Do you know what is this event?
    http://download.oracle.com/docs/cd/E14072_01/server.112/e10820/waitevents003.htm#insertedID148

    Oracle continues to create/add new wait events with every release

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