The SGIO system option greatly improves I/O performance for SAS I/O files (data sets, catalogs,
indexes, utility files, and other I/O files) when the PC has a large amount of RAM. Scatter-read / gather-write bypasses
intermediate buffer transfers between memory and disk.
When SGIO is active, SAS uses the number of buffers that are specified by the BUFNO
system option to transfer data between disk and RAM. I/O performance usually
improves as the value for the BUFNO increases. Try different values
of the BUFNO system option to tune each SAS job or DATA step.
The scatter-read / gather-write
feature is active only for the following SAS
I/O files:
-
those that contain a 4K-multiple
page size (for example, 4096 or 8192) on 32–bit systems
-
those that contain a 8K-multiple
page size (for example, 8192 or 16384) on 64-bit systems
-
those that were not created by
using Version 6 of SAS
-
those that are accessed sequentially.
If an
I/O file does
not meet these criteria, SGIO is inactive for that file even though
the SGIO option is specified. You can access more information about
SGIO in the
SGIO Usage document.