This option improves
performance by specifying a number of rows that can be held in memory
for input into SAS. Buffering data reads can decrease network activities
and 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to the SAS application might be out of date.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 are retrieved in one fetch operation. If READBUFF= is not set, certain
operations such as
SQL SELECT statements cause the number of rows to be set to the client's default value,
which for the engine is one row at a time. Setting READBUFF=128 can significantly
boost the application's performance.
If you do not specify
a value with this option, the engine calculates the buffer size based
on the row length of your data (with a minimum of 10) and retrieves
the number of rows in each fetch operation.