Topics for Database Administrators

Maximizing SYSTEM 2000 Performance

Among the factors that affect SYSTEM 2000 performance are the size of the database being accessed, the number of items being accessed, and the number of data records qualified by the selection criteria. For databases that have many items and many data records, you should evaluate all SAS programs that need to access the database directly. In your evaluation, consider the following:

Does the program need all the SYSTEM 2000 items? If not, create and use an appropriate view descriptor that includes only the items that are needed.
Do the selection criteria retrieve only those data records needed for subsequent analysis? If not, specify different conditions so that the selected records are restricted for the program being used.
Is the data going to be used by more than one procedure in one SAS session? If it is, consider extracting the data and placing it in a SAS data file for SAS procedures to use, instead of the data being accessed directly by each procedure. See Performance Considerations for circumstances when extracting data is the more efficient method.
Do the records need to be in a specific order? If they do, include a SYSTEM 2000 ordering-clause in the appropriate view descriptors or an ORDER BY clause in a SAS program.
Do the selection criteria enable SYSTEM 2000 to use key (indexed) items and non-key (not indexed) items efficiently? See where-clause in SYSTEM 2000 for guidelines for specifying efficient selection criteria.
What kind of locking mechanism will SYSTEM 2000 need to use? See Locking Record Levels.

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