Re: Documentation for reasons to NOT use RAC?
- From: Anupam Pandey <my.oralce@xxxxxxxxx>
- To: yong321@xxxxxxxxx
- Date: Wed, 19 May 2010 10:12:48 +0530
Yong .
Even if you dont specify the parallel hint in query, based on few
heuristics ORACLE calculates if this query should be run in parallel mode or
not and what the degree of parallelism it should have .Though this is
possible only if auto DOP is enabled .
The decision to use parallel execution and the DOP chosen are based on the
resource requirements of a statement. If the estimated elapse time for the
statement is less than PARALLEL_MIN_TIME_THRESHOLD (default is AUTO which
meaning 10 seconds) the statement will run serial.
Thanks ,
Anupam
On Wed, May 19, 2010 at 8:44 AM, Yong Huang <yong321@xxxxxxxxx> wrote:
> > > I don't see how developers should write code differently
> >> if the code needs to be deployed to RAC.:
> >
> > Its not just being TAF/FAN aware, see Gints Plivna's comments
> > earlier in this thread.
>
> Tony,
>
> I understand Gints Plivna's and kathy duret's responses at
>
> //www.freelists.org/post/oracle-l/Documentation-for-reasons-to-NOT-use-RAC,23
>
> They both proposed great ideas for application server admins. The only
> thing developers should do a little differently is perhaps "Use of parallel
> in queries to take advantage of the Rac power", but that's not really
> RAC-specific.
>
> In short, the developers don't need to do anything special for RAC. DBAs
> and mid-tier administrators do.
>
> Yong Huang
>
>
>
> --
> //www.freelists.org/webpage/oracle-l
>
>
>
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