Re: enq HW - contention waits

From: Ravi Gaur <ravigaur1_at_gmail.com>
Date: Fri, 18 Apr 2008 21:14:14 -0500
Message-ID: <289232290804181914p59b0d981k6b697bd058c79a16@mail.gmail.com>


Hello Rajiv,
Yes, we use ASSM. I think I'll have to wait for the situation to recur for the 10045 trace. I can provide the AWR for the 30min interval when this was happening, if that helps.

Thank you,
- Ravi

On Fri, Apr 18, 2008 at 7:03 PM, Rajeev Prabhakar <rprabha01_at_gmail.com> wrote:

> Hello Ravi,
>
> Are you using ASSM (auto OR manual) ? Can you take a 10046
> trace for one of those sessions which is waitng on the "enq: HW -
> contention" and tell us about the kind of blocks that are showing/
> experiencing these kinds of waits and any other observations that
> you can make from those traces ?
>
> -Rajeev
>
> On Fri, Apr 18, 2008 at 4:33 PM, Ravi Gaur <ravigaur1_at_gmail.com> wrote:
> > Greetings,
> >
> > We have a production database running on RAC (4-node) (10.2.0.3 on
> Solaris
> > 10) and I'm noticing a lot of waits on "enq: HW - contention". Doing a
> bit
> > of researching tells me that it is related to HWM extensions (concurrent
> > inserts). We have no control on the application so I wonder what could
> be
> > done from the database end to tune this up (if anything). Here's what I
> see
> > from the AWR during the time it showed up --
> >
> > Top 5 Timed Events
> > EventWaitsTime(s)Avg Wait(ms)% Total Call TimeWait Class
> > CPU time 7,148 43.5
> > enq: HW - contention67,0345,2637932.0Configuration
> > SQL*Net break/reset to client61,0061,504259.2Application
> > db file sequential read152,43188565.4User I/O
> > gc cr block busy34,315490143.0Cluster
> > Any help is deeply appreciated!!
> >
> > TIA,
> > - Ravi Gaur
>

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Received on Fri Apr 18 2008 - 21:14:14 CDT

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