topic Re: Question about REALMEMSIZE option in SAS Programming

Question about REALMEMSIZE option

jvidalg — Tue, 13 Jan 2009 17:18:03 GMT

I have a question about REALMEMSIZE option.

Definition says: Some SAS procedures use the REALMEMSIZE option to specify how much virtual memory the procedure can allocate and use without inducing excessive page swapping.

Then, I suppose is a parameter to control page swapping and to avoid excessive page swapping.

How does it prevent swapping??,

If the systems needs more memory than real memory available, then it starts to swap until the total memory reach the value of REALMEMSIZE, is correct??.
Is a limit value for the page swapping??

Any information about REALMEMSIZE working will be greatly apreciatted.

Thanks in advance.

Re: Question about REALMEMSIZE option

sbb — Tue, 13 Jan 2009 18:28:57 GMT

A few options to gain some technical reference items:

1) a Google advanced search below, strictly against the SAS.COM domain/website:

+REALMEMSIZE site:sas.com

2) the SAS support website http://support.sas.com/ and its SEARCH facility - you will find SAS-hosted DOC and additional technical reference information on the topic.

Scott Barry
SBBWorks, Inc.

Re: Question about REALMEMSIZE option

jvidalg — Wed, 14 Jan 2009 12:28:20 GMT

Thanks for your help. I've found very useful docs

Another question, if I have a proc sort, and I want to avoid page swaping, is that the correct values for the following parameters?

MEMSIZE <= virtual memory (RAM + swap)
REALMENSIZE = (RAM - memory used S.O other apps) <= RAM
SORTSIZE <= REALMEMSIZE

Re: Question about REALMEMSIZE option

jvidalg — Wed, 14 Jan 2009 12:28:47 GMT

Re: Question about REALMEMSIZE option

jvidalg — Wed, 14 Jan 2009 12:33:28 GMT

Sorry I had a problem posting reply

Thanks for your help. I've found very useful docs

Another question, if I have a proc sort, and I want to avoid page swaping, is that the correct values for the following parameters?

MEMSIZE lower or equal than virtual memory (RAM + swap)
REALMEMSIZE= (RAM - memory used by O.S. + other apps) loweor or equal than RAM
SORTSIZE lower or equal than REALMENSIZE

Re: Question about REALMEMSIZE option

sbb — Wed, 14 Jan 2009 14:24:18 GMT

Another Google advanced search argument opportunity listed below - found several related documents on the topic:

sort swapping performance memsize site:sas.com

Also, suggest you create a new post for each new query / question / problem.

Scott Barry
SBBWorks, Inc.