Re: RAC PARALLEL
- From: Sanjay Mishra <smishra_97@xxxxxxxxx>
- To: "tim@xxxxxxxxx" <tim@xxxxxxxxx>, "oracle-l@xxxxxxxxxxxxx" <oracle-l@xxxxxxxxxxxxx>
- Date: Wed, 12 Oct 2011 11:42:59 -0700 (PDT)
Thanks Tim. This is working fine in non-RAC but surely the hitter in the RAC
environment. So look like tuning in RAC setup is required. Also as I mentioned
earlier all of the topmost in Ordered by Read are using same PARALLEL Hints.
Is there any good practices for Parallel_xx parameter setting for RAC
environment like Parallel_instance_group or so
Sanjay
________________________________
From: Tim Gorman <tim@xxxxxxxxx>
To: Sanjay Mishra <smishra_97@xxxxxxxxx>; oracle-l@xxxxxxxxxxxxx
Sent: Wednesday, October 12, 2011 2:18 PM
Subject: Re: RAC PARALLEL
Sanjay,
You've a lot of SQL tuning to do, my friend! :-)
Next step, go to the "SQL Ordered by Reads" section of the same AWR report and
start tuning the first couple of SQL statements on that list. Enjoy!
Thanks!
-Tim
-----Original Message-----
>From: Sanjay Mishra [mailto:smishra_97@xxxxxxxxx]
>Sent: Wednesday, October 12, 2011 12:14 PM
>To: tim@xxxxxxxxx, oracle-l@xxxxxxxxxxxxx
>Subject: Re: RAC PARALLEL
>
>
>Tim
>
>
>Thanks for the detailed update. Here is top events which are not indicating
>much on the gc events.
>
>Top 5 Timed Foreground Events
>Event
>Waits
>Time(s)
>Avg wait (ms)
>% DB time
>Wait Class
>db file sequential read 32,512,212 200,101 8 69.58 User I/O
>DB CPU 40,112 11.30
>db file scattered read 2,123,189 29,289 13 10.51 User I/O
>db file parallel read 161,091 4,058 25 2.01 User I/O
>PX Nsq: PQ load info query 20,702 3,689 189 1.23 Other
>
>
>
>
>Sanjay
>
>
>________________________________
>From: Tim Gorman <tim@xxxxxxxxx>
>To: smishra_97@xxxxxxxxx; oracle-l@xxxxxxxxxxxxx
>Sent: Wednesday, October 12, 2011 1:51 PM
>Subject: Re: RAC PARALLEL
>
>
>Sanjay,
>
>RAC is an amplifier of waits on I/O and enqueues. Assuming that you've gone
>"vanilla" in your 11g upgrade and not propagated forward any strange settings
>in initialization parameters from your previous environment, then whereever
>you might have seen waits on I/O (i.e. "db file sequential read", "db file
>scattered read", etc) in your non-RAC environment, you'll now see those waits
>along with corresponding RAC global cache (GCS) waits in addition. Whereever
>you might have seen waits on enqueues (i.e. events beginning with "enq:") in
>your non-RAC environment, you'll now see corresponding RAC global enqueue
>(GES) waits in addition. These additional GCS and GES waits would be the
>"price of RAC" from the standpoint of performance, and are to be expected. If
>this is the situation you are seeing, then your response is the same in a RAC
>environment as in a non-RAC environment - tune the SQL to
reduce I/O, and analyze/understand/minimize enqueue activity. As the waits on
the basic I/O and enqueue events decrease, so will the waits on the dependent
RAC-related GCS and GES events decrease.
>
>The main point is that wait-event analysis will tell you whether you're
>experiencing "normal" additional waits on GCS and GES piled on top of the
>non-RAC waits you were accustomed to seeing in your non-RAC environment. If
>you are seeing any other excessive waits on events, or any pattern to your
>waits other than that described above, then please consider posting
>information from an AWR report to the list (particularly the "Top Five Timed
>Events" section of the AWR report), and we'll do our best to help you diagnose
>it with you.
>
>Hope this helps...
>
>Thanks!
>
>-Tim
>
>
>
>-----Original Message-----
>>From: Sanjay Mishra [mailto:smishra_97@xxxxxxxxx]
>>Sent: Wednesday, October 12, 2011 11:23 AM
>>To: oracle-l@xxxxxxxxxxxxx
>>Subject: RAC PARALLEL
>>
>>Hi
We have one environment on Sun Infrastructure where we are planning to move to
RAC on 11g. So move is from non-RAC to 4-Node 11g R2 RAC. Database is OLTP,
Partitioned Tables/Indexes and Apps is using heavily PARALLEL and
PARALLEL_INDEX hints. What is the point to consider for the setup. Saw that we
hit some big performance in Test setup and look like it may be due to Paralell
setup. any good sugestion or best practices on RAC setup TIA
Sanjay --
//www.freelists.org/webpage/oracle-l
>
>
--
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