The buffer number is
not a permanent attribute of the data set; it is valid only for the
current SAS session or job.
BUFNO= applies to SAS
data sets that are opened for input, output, or update.
A larger number of buffers
can speed execution time by limiting the number of input and output
(I/O) operations that are required for a particular SAS data set.
However, the improvement in execution time comes at the expense of
increased memory consumption.
To reduce I/O operations
on a small data set as well as speed execution time, allocate one
buffer for each page of data to be processed. This technique is most
effective if you read the same observations several times during processing.
To request that SAS
allocate the number of buffers based on the number of data set pages
and index file pages, use the SASFILE global statement.
Operating Environment Information: The
default value for BUFNO= is determined by your operating environment
and is set to optimize sequential access. To improve performance for
direct (random) access, change the value for BUFNO=. For the default
setting and possible settings for direct access, see the BUFNO= data
set option in the SAS documentation for your operating environment.