Re: _cost_equality_semi_join, Peoplesoft, performance issues

I have updated a few Peoplesoft systems and I have never changed this particular init.ora parameter. Two that I know of (with the potential of) causing performance problems in Peoplesoft on 9i are

_b_tree_bitmap_plans
and
_complex_view_merging

They changed from false to true from 8i to 9i and I know many Peoplesoft installations running on 9i set these back to false. John Clarke wrote:

> I've recently taken on the role of a DBA for a Peoplesoft upgrade projec=
> t and have a question about =5Fcost=5Fequality=5Fsemi=5Fjoin.
>
> We're running Oracle 9.2.0.3 on HP-UX 11.00, upgrading from Peoplesoft 7=
> .5 to 8.<something>. During this little project, we'll be upgrading from=
> 7.3.4 to 9iR2, upgrading HP-UX from 11.00 to 11i, and upgrading Peoples=
> oft and its tools, but due to where we're starting and what sort of hard=
> ware we're on, we need to upgrade from 7.3.4 to 9.2.0.3 first, then upgr=
> ade Peoplesoft, then upgrade HP-UX to 11i, then patch Oracle up to 9.2.0=
> .5 or 6.
>
> Anyway ...
>
> Since we'll be running Peoplesoft 7.x against 9.2.0.3 for a month or so,=
> we're in the middle of doing performance/load testing with the version =
> combination. We've found a handful of performance issues that are relate=
> d to us setting =5Fcost=5Fequality=5Fsemi=5Fjoin to FALSE, the non-defau=
> lt value.
>
> We did this b/c we've found documentation recommending doing this, plus =
> a handful of postings in various places have done this against 9.2.0.3.
>
> My understanding is that =5Fcost=5Fequality=5Fsemi=5Fjoin needed to be s=
> et to FALSE to circumvent a bug that happens during the Peoplesoft upgra=
> de process, but I'm not sure since my sources are varied and unreliable.
>
> Does anyone have experience with this parameter against 9.2.0.3, specifi=
> cally in the context of Peoplesoft=3F If so, I'd be curious to see what =
> sorts of behavior you've seen.
>
> Thanks,
>
> John
>
> --
> http://www.freelists.org/webpage/oracle-l
>

-- 
Regards

Wolfgang Breitling
Centrex Consulting Corporation
www.centrexcc.com
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