AW: Re: AW: Re: AW: Re: amm vs. asmm

thanks a lot for the information. especially the remark about AIX.

Regards
Ahmed

• Original-Nachricht --- Von: Stefan Koehler Betreff: Re: AW: Re: AW: Re: amm vs. asmm Datum: 24.01.2020, 10:46 Uhr An: ahmed.fikri_at_t-online.de Cc: oracle-l_at_freelists.org

Hello Ahmed,
there are also problems with ASMM, e.g. https://twitter.com/jolliffe/status/1094195271448186881?s=20 <https://twitter.com/jolliffe/status/1094195271448186881?s=20> .

There is no better way than doing malloc() or mmap() on your own - just kidding ;-)

I see no reason to change Oracle's memory management if nobody currently faces any issue. However in general I personally favor ASMM (or completely manual SHM management) from the start but why changing something that does work right now in your case. By the way even some guys from Oracle do not favor AMM in first place, e.g.

https://twitter.com/MikeDietrichDE/status/666564901536727040?s=20
<https://twitter.com/MikeDietrichDE/status/666564901536727040?s=20> or 
https://mikedietrichde.com/2016/03/04/parameter-recommendations-for-oracle-database-12c-part-i
<https://mikedietrichde.com/2016/03/04/parameter-recommendations-for-oracle-database-12c-part-i> 

P.S.: Moving Oracle away from AIX is almost always a good idea (not just in case of current problems). IMHO there is only one good reason (real need for best single thread CPU performance) to stay on Power / AIX - but then you need to configure SMT carefully and benchmark it as well.

Best Regards
Stefan Koehler

Independent Oracle performance consultant and researcher Website: http://www.soocs.de <http://www.soocs.de> Twitter: _at_OracleSK <mailto:_at_OracleSK>

> "ahmed.fikri_at_t-online.de <mailto:ahmed.fikri_at_t-online.de> " <
ahmed.fikri_at_t-online.de <mailto:ahmed.fikri_at_t-online.de> > hat am 24. Januar 2020 um 10:11 geschrieben:
>
> hello Steffen,
>
> it is just an observation that we have made in the past. After we heard
that there are problems with AMM (I guess from you too in DOAG :-) ). I did few performance tests and have very negative impact of AMM on our application. In addition to that I doubt that the DBA has a factual reason to use AMM. It was may be only coincidence. Furthermore I'm worried that someone will look elsewhere for current performance problems. For example, to believe that the solution is to use a different OS ;-)
>
> Grüße
> Ahmed

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