The LIBNAME Statement for Relational Databases

SPOOL= LIBNAME Option

Specifies whether SAS creates a utility spool file during read transactions that read data more than once.

Default value:	YES
Valid in:	SAS/ACCESS LIBNAME statement
DBMS 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, Teradata

Syntax
Syntax Description
Details
See Also

Syntax

SPOOL=YES | NO | DBMS

Syntax Description

YES: specifies that SAS creates a utility spool file into which it writes the rows that are read the first time. For subsequent passes through the data, the rows are read from the utility spool file rather than being re-read from the DBMS table. This guarantees that the row set is the same for every pass through the data.
NO: specifies that the required rows for all passes of the data are read from the DBMS table. No spool file is written. There is no guarantee that the row set is the same for each pass through the data.
DBMS: is valid for Oracle only. The required rows for all passes of the data are read from the DBMS table but additional enforcements are made on the DBMS server side to ensure that the row set is the same for every pass through the data. This setting causes SAS/ACCESS Interface to Oracle to satisfy the two-pass requirement by starting a read-only transaction. SPOOL=YES and SPOOL=DBMS have comparable performance results for Oracle. However, SPOOL=DBMS does not use any disk space. When SPOOL is set to DBMS, you must set CONNECTION=UNIQUE or an error occurs.

Details

In 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 of a data read to a spool file. In the second pass, rows can be reread without performing I/O to the DBMS a second time. When data must be read more than once, spooling improves performance. Spooling also guarantees that the data remains the same between 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 statements to Teradata twice. Additionally, because the Teradata table can be modified between passes, SPOOL=NO can cause data integrity problems. Use SPOOL=NO with discretion.