Re: V$session_wait.seconds_in_wait

From: Charles Hooper <hooperc2000_at_yahoo.com>
Date: Tue, 22 Jul 2008 07:36:05 -0700 (PDT)
Message-ID: <e8d3a54c-2544-4729-b03f-dfae80f44fd9@i76g2000hsf.googlegroups.com>


On Jul 22, 9:42 am, Mark D Powell <Mark.Pow..._at_eds.com> wrote:
> A very complete answer to this same question was posted on the OTN
> database forum today.
>
> The Oracle version# Reference Manual includes coverage of this v$ view
> and the meaning of its columns.  The time units in the view vary by
> Oracle release and are the values are only approximate wait times.
>

Thanks for the heads up. Jonathan's answer is a bit different than mine... read that as I think that I have found that my notes are either out of date or were never correct, but in either case, Jonathan's answer is both correct and complete.

I believe that my noted originated from this document, one one very similar (the original source could have been the author's book): "Tuning Oracle Without Cache-Hit Ratios" http://www.quest-pipelines.com/newsletter-v3/0402_C.htm "If State = (Waiting or Waited Unknown Time or Waited Short Time) then
  Wait_Time = Irrelevant;
End If;
If State = (Waited Known Time) then
  Wait_Time = Actual wait time, in seconds; End If;"

It appears that the syntax in the Oracle reference manuals has been clarified related to this performance view: 8i Release 2 Reference:
http://download.oracle.com/docs/cd/A87860_01/doc/server.817/a76961/ch3142.htm WAIT_TIME, If > 0 - WAITED KNOWN TIME (WAIT_TIME = duration of last wait)

10g Release 2 Reference:
http://download.oracle.com/docs/cd/B19306_01/server.102/b14237/dynviews_2094.htm WAIT_TIME, If > 0 - WAITED KNOWN TIME (WAIT_TIME = duration of last wait)

11g Release 1 Reference:
http://download-uk.oracle.com/docs/cd/B28359_01/server.111/b28320/dynviews_3023.htm WAIT_TIME, If > 0 - Value is the duration of the last wait in hundredths of a second

I am beginning to wonder if WAIT_TIME was ever expressed in whole seconds, and not always as hundredths of a second.

Time to update my notes...

Charles Hooper
IT Manager/Oracle DBA
K&M Machine-Fabricating, Inc. Received on Tue Jul 22 2008 - 09:36:05 CDT

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