Re: AIX 4.2 and Oracle 7.2/7.3 SGA/PGA and virtual memory

Steve Phelan wrote:
>
> Jens Wartenberg wrote:
> >
> > Hi.
> >
> > Can you help me with a question regarding aix-behavior?
> >
> > SHORT:
> > ------
> > I understand that AIX uses almost all not actively used RAM for
> > "disk-cache" for the jfs (not using raw devices!). I am hovever not sure
> > which of the following is "true":
> >
> > Examples: MB
> > --------- ----
> > RAM: 128
> > Paging space: +256
> >
> > Assumption 1: (I believe this is "true")
> > -------------
> > Base consumption of RAM (SGA, AIX etc.): 50
> > ACTIVE usersessions (30sessions*3MB*50%): 45
> > --
> > 95
> > Available for "disk-cache" (128 - 95): 33
> >
> > Assumption 2: (I hope this is not "true")
> > -------------
> > Base consumption of RAM (SGA, AIX etc.): 50
> > Usersessions (ALL) (30sessions*3MB*100%): 90
> > -----
> > 140
> > Available for "disk-cache" (128 - 140): (none)
> > (I should be able to see more than very little paging activity when
> > using vmstat).
> >
> > If assumption 1 is "true", I will allocate 33MB ram more the Oracle
> > SGA/PGA (using the values of the above example).
> > If assumption 2 is "true", I will probably recommend the customer to buy
> > more RAM.
> >
> > LONGER VERSION FOR UNDERSTANDING:
> > ---------------------------------
> > I am working on getting the most out of Oracle-based applications in
> > AIX-environments. The applications are integrated (MPS, Economy etc.) to
> > cover 90%-95% of the needs of manufacturing companies. The main tables
> > contain 1-10 million rows, and the database has a size of 4-14GB.
> >
> > Most of my customers has 2-4 AIX+Oracle sessions pr. user, so the most
> > frequently used functions are "at the fingertips". This means, that most
> > of the time 50%-70% of the sessions are "sleeping".
> >
> > My problem is, how I should size the Oracle-SGA/PGA with this memory-use
> > in mind.
> > MY AIM IS to use the RAM available for active Oracle in stead of for
> > aix-disk-cache, as Oracle should manage the cache more efficient as a
> > result of having different priorities for index-data and table-data. Aix
> > is of course not able to prioritize disk-cache in this manner.
> >
> > Most of my customers seem to have to little memory allocated to SGA/PGA
> > (13-25MB), resulting in a lot of I/O activity which of course is bad for
> > performance.
> >
> > I HAVE tried to study some books on the subject, but I am not sure about
> > the behavior.
> >
> > Thank you in advance for any comment.
> >
> > Regards
> >
> > Jens Wartenberg
> > Wartenberg Industri Data
> > Denmark
> Have you considered using Multi-threaded server in your calculations?
>
> Steve Phelan.

No (and yes). Confused?

The application is still forms 3.0 based, so the server is also executing the forms. There is almost no sqlnet usage.

Thanks a lot for your reply

Jens Wartenberg Received on Wed Mar 05 1997 - 00:00:00 CST