You can use global macro
variables in SPD Server to simplify your work. Global macro variables
use default values set by SPD Server and operate in the background.
You can make global changes to the values of macro variables in your
code by specifying a new default setting for the specified variable.
The new default setting is applied to all macro variables in the code
that you submit to SPD Server. You can override the setting for a
single macro variable by using a table option to change the setting
for only the specified table.
The default macro variable
values automate sophisticated processing decisions. The default settings
provide good performance. However, optimal performance requires intelligent
changes to some macro variable default settings. When you make changes
to the macro variable default settings, you should find the best processing
opportunity for the type of data that you have.
Learning the best way
to set SPD Server macro variables and options takes time. Sometimes,
performance testing is the only way to determine whether changing
a setting improves processing performance. Performance testing is
time well spent. After you quantify performance parameters under various
macro variable settings, you can customize SPD Server so that it solves
your real business or data problems with maximum efficiency.
Each SPD Server installation
is different. You might want to change many values, or just a few.
When you make changes, you will learn that macro variables are flexible
and easy to manipulate.
Use a %LET statement
to change macro variable values. You can place the macro variable
assignment anywhere in the open code of a SAS program except in the
data lines. The most convenient location for your %LET statements
to initialize macro variables is in your autoexec.sas file or at
the beginning of a program. The macro variable assignment is valid
for the duration of your session or the executing program. Macro variable
values remain in effect until they are changed by a subsequent assignment.
Assignments for macro
variables with YES or NO arguments must be uppercase.
Because SPD Server macro
variables operate behind the scenes, you cannot query SPD Server to
determine the status of a macro variable. SAS does not know about
the status of macro variables. If you want to know which SPD Server
macro variables are in effect, or what their default values are, you
can use PROC SPDO.