Re: Performance with SCAN listener in 11g RAC

  • From: Guillermo Alan Bort <cicciuxdba@xxxxxxxxx>
  • To: Lu Jiang <lu.jiang69@xxxxxxxxx>
  • Date: Thu, 2 May 2013 11:20:15 -0300

Did you run a trace on all the sessions? are you sure the query is exactly
the same and that the generated plan is the same? are you clearing the
buffer cache between runs? this sounds like the second result is cached and
therefore faster...
and to answer your question, no, there is no guideline for stats gathering
in RAC vs single instance, the differences are usually somewhere in the
application logic (stuff that manages concurrency) or the data model design.

hth

Alan.-


On Thu, May 2, 2013 at 11:10 AM, Lu Jiang <lu.jiang69@xxxxxxxxx> wrote:

> Hi DBA gurus,
>
> I am do a performance test. Find that running same query using tns
> connection string with SCAN host name is 5 seconds slow than using tns
> connection string points to a specific host name (17seconds  VS. 12
> seconds). Is this normal?
> Is there are any special requirement to run gather schema stats tasks in a
> RAC environment?
> Could anyone shed light on these?
>
> Thanks,
> Lu
> --
> //www.freelists.org/webpage/oracle-l
>
>
>


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