Re: Any tools/scripts for finding underlying cause of concurrency?
From: <stevedhoward_at_gmail.com>
Date: Wed, 11 Mar 2009 08:40:41 -0700 (PDT)
Message-ID: <9780fe5b-7b5d-496e-b662-c92895653407_at_r36g2000prf.googlegroups.com>
On Mar 8, 11:56 am, vm22 <vivekmarw..._at_gmail.com> 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
Date: Wed, 11 Mar 2009 08:40:41 -0700 (PDT)
Message-ID: <9780fe5b-7b5d-496e-b662-c92895653407_at_r36g2000prf.googlegroups.com>
On Mar 8, 11:56 am, vm22 <vivekmarw..._at_gmail.com> 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