One more thing, an MDDB is created in memory. This means that you need enough memory (= physical memory + available swap space) to store the complete NWAY subtable in memory.

From the Application Development with The SASŪ System, Release 6.12 course notes you can calculate how much memory you will need:

> To predict the size of an MDDB, you need to know the following. > > - Number of analysis variables (na) > - Number of class variables (nc) > - Maximum formatted length of each class variable (mlc) > - Length of each class variable (lc) > - Number of distinct values in each class variable (dv) > - Number of valid crossings between class variables for each table (vc) > > The formula for the size of an MDDB is: > > for every mddb: .............................................. 164 bytes > for every analysis variable: ...................................28 bytes > for every class variable: ...................32 bytes + (mlc*dv + lc*dv) > for each table/subtable: .......................................84 bytes > for each subtable: ...((na+nc+2)*sizeof(int) + (na*ns*sizeof(double))*vc

Cheers, Bart Heinsius E.O.M. Data The Netherlands http://www.eomdata.nl

> -----Original Message----- > From: SAS(r) Discussion [mailto:SAS-L@LISTSERV.UGA.EDU]On Behalf Of Bart > Heinsius > Sent: woensdag 27 september 2000 22:23 > To: SAS-L@LISTSERV.UGA.EDU > Subject: Re: Create MDDB - out of memory (was: Sizing - How to ?) > > > > ... the PROC MDDB is unable to generate the MDDB, and gives the error > > "Unable to perform function, memory exhausted". > Is your memsize set to 0 in your config.sas612? > If so, there is a kernel parameter that restricts the total > amount of memory > that any process on the machine can use. On our machine (HP-UX), this was > originally set at 64MB. Ask your system administrator what it's set to and > let him make it larger. > > > 4. Does Proc MDDB use swap ? my swap is hardly used when I run > PROC MDDB. > Proc mddb creates the subtables in memory, so when it is running out of > physical memory, swap space will be used. The reason that you > don't see swap > space being used may be due to the memsize or the kernel parameter setting > described above. > > Cheers, > Bart Heinsius > E.O.M. Data > The Netherlands > http://www.eomdata.nl > > > > -----Original Message----- > > From: SAS(r) Discussion [mailto:SAS-L@LISTSERV.UGA.EDU]On Behalf Of > > Deepak Mathur > > Sent: dinsdag 26 september 2000 9:06 > > To: SAS-L@LISTSERV.UGA.EDU > > Subject: Sizing - How to ? > > Importance: High > > > > > > Hi all, > > > > I am facing a problem. I have a huge summary dataset on which I > > create a big > > MDDB. The summary dataset is appended with a snapshot of some data every > > month. The MDDB uses month and year as a dimension.However, for > > the past two > > months the PROC MDDB is unable to generate the MDDB, and gives the error > > "Unable to perform function, memory exhausted". > > > > I have been asked to suggest the memory upgrade required.Note > > that it is not > > possible for me to split the MDDB etc right now. I am willing > to invest in > > H/w resources. > > > > At this point, I need to know the following: > > 1. How does one find cardinalities ? > > 2. How does one estimate the memory required to generate a > > particular MDDB ? > > > > 3. What other problems can cause the error I've mentioned above ? > > 4. Does Proc MDDB use swap ? my swap is hardly used when I run > PROC MDDB. > > > > Site details : SAS 6.12 on AIX 4.2.1 (RS/6000) 512 MB RAM > > MDDB Details (the problem one) : > > Dimensions : 17 Measures : 35 > > Cells (Nway) : 291,620 > > Rows in summary dataset : 3,632,434 > > > > Thanks in advance, > > Deepak > > > > > _________________________________________________________________________ > > Knowledge is Power. > > > > Deepak Mathur, IT > > Extn: 5079 > > Orange:18299 > > > _________________________________________________________________________ > > >