Re: "gc current block busy" wait in Concurrent BATCH Processes Run
- From: "Finn Jorgensen" <finn.oracledba@xxxxxxxxx>
- To: VIVEK_SHARMA@xxxxxxxxxxx
- Date: Wed, 13 Feb 2008 12:27:23 -0500
gc means global cache, which means it's cache fusion/interconnect related.
More than likely you have processes on both/all nodes of the cluster writing
to the same table(s) and cache fusion is having trouble keeping up with the
communication of which blocks are dirty (and sending the data back and
forth) and which are not.
In my experience with RAC, if you have a lot of writes to a set of tables
you're much better off localizing all those connections on one node so you
don't have the "gc" wait events. Throughput goes up as well.
Not exactly what Oracle is marketing when they talk about RAC, but that has
been my experience.
Finn
On 2/13/08, VIVEK_SHARMA <VIVEK_SHARMA@xxxxxxxxxxx> wrote:
>
>
> Folks
>
> In a Benchmark Run, 256 concurrent BATCH Processes on RAC using Dedicated
> Sessions (NON-MTS) showing the following Waits:-
>
> How is the "gc current block busy" wait to be addressed?
> From the Statspack Report (Level 7) which section gives the Objects which
> is incurring this wait? Is it the "Segments By Current Blocks Received"
> section OR the "Segments by CR Blocks Received" section?
>
> Will share the Statspack Report, as needed.
>
> Config:-
> Oracle 10.2.0.3 on 3 Node RAC
> Solaris 10
>
> Cheers
>
> Vivek
>
> Statspack Report's Time Elapsed: 11.97 (mins)
>
>
>
> Top 5 Timed Events
> Avg %Total
>
> ~~~~~~~~~~~~~~~~~~
> wait Call
>
> Event Waits Time
> (s) (ms) Time
>
> ----------------------------------------- ------------ ----------- ------
> ------
>
> CPU time 5,854
> 57.6
>
> gc current block busy 24,910 1,463 59
> 14.4
>
> SQL*Net break/reset to client 1,075,218 1,285 1
> 12.6
>
> gcs log flush sync 103,520 511
> 5 5.0
>
> gc buffer busy 6,489
> 367 57 3.6
>
> -------------------------------------------------------------
>
>
>
> Host CPU (CPUs: 120)
>
> ~~~~~~~~ Load Average
>
> Begin End User System Idle WIO WCPU
>
> ------- ------- ------- ------- ------- ------- --------
>
> 8.58 9.54
>
> 8.26 15.61 76.13 0.00 1.19
>
> **************** CAUTION - Disclaimer *****************
> This e-mail contains PRIVILEGED AND CONFIDENTIAL INFORMATION intended
> solely for the use of the addressee(s). If you are not the intended
> recipient, please notify the sender by e-mail and delete the original
> message. Further, you are not to copy, disclose, or distribute this e-mail
> or its contents to any other person and any such actions are unlawful. This
> e-mail may contain viruses. Infosys has taken every reasonable precaution to
> minimize this risk, but is not liable for any damage you may sustain as a
> result of any virus in this e-mail. You should carry out your own virus
> checks before opening the e-mail or attachment. Infosys reserves the right
> to monitor and review the content of all messages sent to or from this
> e-mail address. Messages sent to or from this e-mail address may be stored
> on the Infosys e-mail system.
> ***INFOSYS******** End of Disclaimer ********INFOSYS***
> --
> //www.freelists.org/webpage/oracle-l
>
>
>
Other related posts:
