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

The LIBNAME Statement for Relational Databases 4 SPOOL= LIBNAME Option 185SPOOL= LIBNAME OptionSpecifies whether SAS creates a utility spool file during read transactions that read data morethan once.Default value: YESValid in: SAS/ACCESS LIBNAME statementDBMS support: Aster nCluster, DB2 under UNIX and PC Hosts, DB2 under z/OS,Greenplum, HP Neoview, Informix, Microsoft SQL Server, MySQL, Netezza, ODBC,OLE DB, Oracle, Sybase, Sybase IQ, TeradataSyntaxSPOOL=YES | NO | DBMSSyntax DescriptionYESspecifies that SAS creates a utility spool file into which it writes the rows that areread the first time. For subsequent passes through the data, the rows are read fromthe utility spool file rather than being re-read from the DBMS table. This guaranteesthat the row set is the same for every pass through the data.NOspecifies that the required rows for all passes of the data are read from the DBMStable. No spool file is written. There is no guarantee that the row set is the same foreach pass through the data.DBMSis valid for Oracle only. The required rows for all passes of the data are read fromthe DBMS table but additional enforcements are made on the DBMS server side toensure that the row set is the same for every pass through the data. This settingcauses SAS/ACCESS Interface to Oracle to satisfy the two-pass requirement bystarting a read-only transaction. SPOOL=YES and SPOOL=DBMS have comparableperformance results for Oracle. However, SPOOL=DBMS does not use any diskspace. When SPOOL is set to DBMS, you must set CONNECTION=UNIQUE or anerror occurs.DetailsIn some cases, SAS processes data in more than one pass through the same set of rows.Spooling is the process of writing rows that have been retrieved during the first pass ofa data read to a spool file. In the second pass, rows can be reread without performingI/O to the DBMS a second time. When data must be read more than once, spoolingimproves performance. Spooling also guarantees that the data remains the samebetween passes, as most SAS/ACCESS interfaces do not support member-level locking.MySQL: Do not use SPOOL=NO with the MySQL interface.Teradata: SPOOL=NO requires SAS/ACCESS to issue identical SELECT statementsto Teradata twice. Additionally, because the Teradata table can be modified betweenpasses, SPOOL=NO can cause data integrity problems. Use SPOOL=NO withdiscretion.