Re: RAC is slower than non-RAC for batch job with lots of update/delete?

Hi Charles

Have a look at Julian Dykes excellent RAC Presentation: Inside RAC

Thanks

--
LSC


On 10/18/07, Charles Schultz <sacrophyte_at_gmail.com> wrote:


>

> Yes, pgs 236-239 really spell that out quite well, thanks.

> However, I am still unclear if you can explicitly remaster a resource.

> From the verbiage, it sounds like the answer is no. Is it a feasible

> workaround to dynamically reset _gc_affinity_limit to some low value (say,

> 1) at the beginning of the batch job, than reset it afterwards?

> Unfortunately, this would also cause havoc if anything else is running on

> both nodes. I see that the affinity time and _lm_dynamic_remastering are

> both static parameters, so it would be hard to play with them unless you

> bounce the database.

>

> Aside from application partitioning, what is the best way to handle

> "sequential" jobs?

>

> On 10/18/07, K Gopalakrishnan <kaygopal_at_gmail.com> wrote:

> >

> > Chuck,

> >

> > > I have heard that the Oracle kernel will keep track of how many times

> > a gc

> > > request is made, and upon hitting a certain threshold, will remaster a

> > > particular block (or table?) to the node making a majority of the

> > requests.

> > > Which makes me wonder. If your batch job is always connecting to a

> > specific

> > > node, could the blocks be mastered explicitly to that node? I ask that

> > of

> > > the list.

> >

> > Yes. The behavior is called Dynamic Resource Mastering. If one object

> > (or set of objects) continuously accessed in one particular node the

> > objects are mastered in that node. Check Chapter 11 (Global Resource

> > Directory) of the 10g RAC Handbook..

> >

> > There used to be some issues  in the past (related to node evictions

> > during DRM) and we turn off the DRM if you are < 10.2.0.3.

> >

> > -Gopal

> >

> > --

> > Best Regards,

> > K Gopalakrishnan

> > Co-Author: Oracle Wait Interface, Oracle Press 2004

> > http://www.amazon.com/exec/obidos/tg/detail/-/007222729X/

> >

> > Author: Oracle Database 10g RAC Handbook, Oracle Press 2006

> > http://www.amazon.com/gp/product/007146509X/

> >

>

>

>

> --

> Charles Schultz


--
http://www.freelists.org/webpage/oracle-l