122 REREAD_EXPOSURE= LIBNAME Option Chapter 9
increase performance. However, because SAS stores the rows in memory, higher values
for READBUFF= use more memory. In addition, if too many rows are selected at once,
then the rows that are returned to the SAS application might be out of date. For
example, if someone else modifies the rows, you do not see the changes.
When READBUFF=1, only one row is retrieved at a time. The higher the value for
READBUFF=, the more rows the DBMS engine retrieves in one fetch operation.
DB2 UNIX/PC, ODBC, and Microsoft SQL Server Details: If you do not specify this
option, the SQLFetch API call is used and no internal SAS buffering is performed (this
is the default). Setting READBUFF=1 or greater causes the SQLExtendedFetch API
call to be used. ROWSET_SIZE is an alias for this option.
OLE DB Details: The default is 1. ROWSET_SIZE is an alias for this option.
Oracle Details: The default is 250.
SYBASE Details: The default is 100.
See Also
To apply this option to an individual data set, see the data set option “READBUFF=
Data Set Option” on page 208.
REREAD_EXPOSURE= LIBNAME Option
Specifies whether the SAS/ACCESS engine behaves like a random access engine for the scope of
the LIBNAME statement
Valid in: the SAS/ACCESS LIBNAME statement
DBMS support: DB2 OS/390, DB2 UNIX/PC, Informix, ODBC, OLE DB, Oracle,
Microsoft SQL Server, SYBASE, Teradata
Default value: NO
Syntax
REREAD_EXPOSURE= NO | YES
Syntax Description
NO
specifies that the SAS/ACCESS engine behaves as an RMOD engine, which means
that your data is protected by the normal data protection that SAS provides.
YES
specifies that the SAS/ACCESS engine behaves like a random access engine when
rereading a row so that you cannot guarantee that the same row is returned. For
example, if you read row 5 and someone else deletes it, then the next time you read
row 5, you will read a different row. You have the potential for data integrity
exposures within the scope of your SAS session.
Details
CAUTION:
Using REREAD_EXPOSURE= could cause data integrity exposures
