Re: enq HW - contention waits

From: Rajeev Prabhakar <>
Date: Fri, 18 Apr 2008 20:03:22 -0400
Message-ID: <>

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 ?


On Fri, Apr 18, 2008 at 4:33 PM, Ravi Gaur <> wrote:
> Greetings,
> We have a production database running on RAC (4-node) ( 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

Received on Fri Apr 18 2008 - 19:03:22 CDT

Original text of this message