Re: Active Session History count(*) vs. sum(time_waited)
From: Austin Hackett <hacketta_57_at_me.com>
Date: Thu, 16 Jan 2014 21:11:23 +0000
Message-id: <47341483-F450-4AF0-9A2E-BD47F81CE403_at_me.com>
Hi
Date: Thu, 16 Jan 2014 21:11:23 +0000
Message-id: <47341483-F450-4AF0-9A2E-BD47F81CE403_at_me.com>
Hi
ASH has a "fix-up" mechanism. For long events the last sample gets it's TIME_WAITED value populated, and all the other samples stay at 0.
If you are seeing sum(time_waited) = 0 then my assumption would be that you have an on-going long wait on SQL*Net more data from client.
I've previously seen "SQL*Net more data from client" when a client process has died mid-stream. If DCD (dead connection detection) is disabled, the individual wait can go on for days. I think the SEQ# column would allow you to validate this - if the SEQ# is always the same, it should be the same wait.
Hope that helps
Austin
-- http://www.freelists.org/webpage/oracle-lReceived on Thu Jan 16 2014 - 22:11:23 CET