RE: Re: RE: Average Wait and Time Waited in Sessions view

Just to give Oracle's seemingly odd choice an explanation. Remember that Oracle has been around a long time and on many hardware/software platforms. A long time ago hundredths of a second was as far as they could go portably - so it became somewhat of a standard. No one likes it much - including Oracle - but there is a reason for what seems like an odd choice :)

From: [email protected] [mailto:[email protected]] On Behalf Of John Dorlon
Sent: Friday, February 10, 2012 8:42 AM
To: [email protected]
Subject: RE: [toad] Re: RE: Average Wait and Time Waited in Sessions view


Well, according to that link I gave you below...Time_waited, max_wait, average_wait are all in hundredths of a second.   Time_waited_micro is microseconds which is millionths of a second.

1/100 * 1/10000 = 1/1000000 = 1 millionth, so it seems right to me.

It would be nice to know what we are looking at here without having to go to Oracle docs.   And I've heard others complain about what an unusual unit hundredths of seconds are.

From: [email protected]<mailto:[email protected]> [mailto:[email protected]]<mailto:[mailto:[email protected]]> On Behalf Of Matt Birchall
Sent: Friday, February 10, 2012 7:11 AM
To: [email protected]<mailto:[email protected]>
Subject: [toad] Re: RE: Average Wait and Time Waited in Sessions view



Message from: Matt Birchall


looking at session browser -> Sessions -> Waits -> Total Waits (rather than current waits)
The Time Waited, Average Wait and Max Wait columns are the items that look wrong to me. Time Waited Micro has been divided by 10,000 rather than 1,000 ?


_______________________________________

Historical Messages


Author: Matt Birchall
Date: Fri Feb 10 05:10:55 PST 2012
looking at session browser -> Sessions -> Waits -> Total Waits (rather than current waits)
The Time Waited, Average Wait and Max Wait columns are the items that look wrong to me. Time Waited Micro has been divided by 10,000 rather than 1,000 ?

__

Author: John Dorlon
Date: Thu Feb 09 09:01:08 PST 2012
Hi Matt, Are you looking at Session Browser -> RHS -> Waits? If so, we are just showing the data from Oracle. We aren't doing anything to change the units (or even display them). That data comes from the v$session_event view, and according to 11g Oracle docs, the time_waited column is microseconds. http://docs.oracle.com/cd/E11882_01/server.112/e25513/dynviews_3020.htm -John
__

Author: Matt Birchall
Date: Thu Feb 09 02:19:53 PST 2012
I've been looking at the disk latency in our system and have looked at the time vs disk read values shown in SGA trace and in the Sessions view.
The Time waited and Average wait columns in the Total Waits breakdown of the Waits tab of the sessions view is a factor 10 lower than reality. The result is that my disks show an impressive 0.89 ms latency when, in reality, the value is 8.9 ms. The time waited micro is correct but the Time Waited column (presumably milliseconds?) and the Average Wait are 10X too small.
(Toad for Oracle Base 11.0.0.116)

__
_______________________________________