Re: Any tools/scripts for finding underlying cause of concurrency?

From: <>
Date: Wed, 11 Mar 2009 08:40:41 -0700 (PDT)
Message-ID: <>

On Mar 8, 11:56 am, vm22 <> wrote:
> We have been having concurrency issues for the past week but have
> managed to resolve it (the underlying cause of it was a bug). One
> thing that I wanted to know is that if there are any tools or scripts
> out there to tell us immediately the cause of the concurrency?
> All we saw in OEM was a couple of statements which were the Top SQL as
> well as a session that was blocking and several being blocked. We
> could not see the underlying SQL that was causing it. Eventually, the
> issue was the UNDO segments being released from a huge transaction -
> thereby causing the concurrency.
> Any help is appreciated.
> Regards,
> Vivek

I'll assume you are on at least 10g (although Top SQL IIRC is a 9i OEM tool). I can't remember if this column is in v$system_event in 9i, but in 10g and above you can always query...

select event_name,time_waited from v$system_event where wait_class = 'Concurrency';

Conversely, you can get the waits in that class from v$event_name.

HTH, Steve Received on Wed Mar 11 2009 - 10:40:41 CDT

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