SAS/ACCESS 9.2 for Relational Databases: Reference, Fourth Edition

Data Set Options for Relational Databases 4 DBSLICEPARM= Data Set Option 317automatic partitioning. For example, a well-tuned DBSLICE= specification might betterdistribute data across threads by taking advantage of a column that SAS/ACCESScannot use when it automatically generates partitioning WHERE clauses.DBSLICE= delivers optimal performance for DB2 under UNIX and for Microsoft SQLServer. Conversely, DBSLICE= can degrade performance compared to automaticpartitioning. For example, Teradata starts the FastExport Utility for automaticpartitioning. If DBSLICE= overrides this action, WHERE clauses are generatedinstead. Even with well planned WHERE clauses, performance is degraded becauseFastExport is considerably faster.CAUTION:When using DBSLICE=, you are responsible for data integrity. If your WHERE clauses omitrows from the result set or retrieves the same row on more than one thread, your inputDBMS result set is incorrect and your SAS program generates incorrect results. 4ExamplesIn this example, DBSLICE= partitions on the GENDER column can have only thevalues m, M, f, and F. This DBSLICE= clause does not work for all DBMSs due to theuse of UPPER and single quotation marks. Some DBMSs require double quotationmarks around character literals. Two threads are created.proc reg SIMPLEdata=lib.customers(DBSLICE="UPPER(GENDER)=’M’" "UPPER(GENDER)=’F’"));var age weight;where years_active>1;run;The next example partitions on the non-null column CHILDREN, the number ofchildren in a family. Three threads are created.data local;set lib.families(DBSLICE=("CHILDREN2" "CHILDREN=2"));where religion="P";run;See Also“DBSLICEPARM= LIBNAME Option” on page 137“DBSLICEPARM= Data Set Option” on page 317DBSLICEPARM= Data Set OptionControls the scope of DBMS threaded reads and the number of DBMS connections.Default value: THREADED_APPS,2 [DB2 under z/OS, Oracle, and Teradata]THREADED_APPS,2 or 3 [DB2 under UNIX and PC Hosts, HP Neoview, Informix,Microsoft SQL Server, ODBC, and Sybase, Sybase IQ]Valid in: DATA and PROC Steps (when accessing DBMS data using SAS/ACCESSsoftware) (also available as a SAS configuration file option, SAS invocation option,global SAS option, and LIBNAME option)