Dear SAS-L-ers,

Arthur Tabachneck posted the following "did you know that":

> Did you know that: There is something you can do to improve > the performance of using count(distinct xxxx) in proc sql? > > Came across the following this morning: > http://support.sas.com/techsup/unotes/SN/019/019372.html >

Art, well, I for one, _DID_ know about this particular option. IBUFNO is covered in my award-winning book, The Complete Guide to SAS Indexes, in Chapter 5, Index-Related Options, The IBUFNO System Option, pp 66 - 67. This option can help PROC SQL-ers as well as DATA steppers. So, I would urge the SAS index-using public to look at this way-cool option.

Hey, as long as we are at it; check out IBUFSIZE, which sets the size of the index pages, themselves. Larger index pages allow more index entries to be transferred per I/O and can reduce the number of levels of an index. This double-whammy can also be good for performance.

Of course, both of these tools require more computer memory than would be used with the SAS-supplied defaults, so the usual caveats apply.

Best of luck to you in all of your SAS endeavors!

I hope that this suggestion proves helpful now, and in the future!

Of course, all of these opinions and insights are my own, and do not reflect those of my organization or my associates. All SAS code and/or methodologies specified in this posting are for illustrative purposes only and no warranty is stated or implied as to their accuracy or applicability. People deciding to use information in this posting do so at their own risk.

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Michael A. Raithel "The man who wrote the book on performance" E-mail: MichaelRaithel@westat.com

Author: Tuning SAS Applications in the MVS Environment

Author: Tuning SAS Applications in the OS/390 and z/OS Environments, Second Edition http://www.sas.com/apps/pubscat/bookdetails.jsp?catid=1&pc=58172

Author: The Complete Guide to SAS Indexes http://www.sas.com/apps/pubscat/bookdetails.jsp?catid=1&pc=60409

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Food is an important part of a balanced diet. - Fran Lebowitz +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++