A SAS LASR Analytic Server table can be partitioned, and it can also be ordered within each partition. A partition is a collection of observations that share the same key value and are located on the same worker node. The key value can be constructed from one or more variables. The partitioning keys are created according to the formatted values of the specified variables. Partitioning of data is an important tool in managing distributed data sources. The process of partitioning can consume computing and network resources as well as create greater imbalance in the data compared to a round-robin distribution. However, partitioned data can be accessed more quickly and subsequent procedure statements can execute more quickly.

You can achieve a partitioned table as follows: For more information, see Data Partitioning and Ordering.

The IMSTAT procedure supports RUN-group processing. RUN-group processing enables you to submit RUN groups without ending the procedure. This feature is particularly useful for running SAS interactively. You can start the procedure with the PROC IMSTAT statement and then execute statements like TABLE and PROMOTE. Each statement runs when it reaches a RUN statement.

To use RUN-group processing, you start the procedure and then submit multiple RUN-groups. A RUN-group is a group of statements that contains at least one action statement and ends with a RUN statement. As long as you do not terminate the procedure, it remains active and you do not need to resubmit the PROC statement.

To end RUN-group processing, submit a RUN CANCEL statement. Statements that have not been submitted are terminated. To stop the procedure, submit a QUIT statement. Statements that have not been submitted are terminated as well.

There are two important features for WHERE clause processing that are related to the IMSTAT procedure. The first is that the WHERE clause is applied to the data by the server. When you use a WHERE clause to subset data, the subsetting is performed by the server and only the rows that meet the WHERE clause criteria are affected by subsequent operations.

The second important feature for WHERE clause processing is related to the RUN-group processing that the IMSTAT procedure supports. You can modify the WHERE clause between statements.

A temporary table is an in-memory table that contains the result set of a procedure statement. Instead of transferring the results to the client SAS session, the results remain in the server and only the name of the temporary table is transferred to the client. You can then use other procedure statements with the temporary table.

Temporary tables are supported for the SUMMARY, CROSSTAB, DISTINCT, and PERCENTILE statements for partitioned data. For non-partitioned data, you can also generate temporary tables with the SUMMARY and CROSSTAB statements, provided that you request a GROUPBY analysis.

data lasr.prdsale(partition=(country region));
    set sashelp.prdsale;
run;

proc imstat;
   table lasr.prdsale;
   summary actual predict / partition;
run;

   summary actual predict / partition temptable;
run;

The temporary table is assigned a name by the server. When the IMSTAT procedure ends, any temporary tables created during the procedure run are removed from the server. Since the generated name is not predictable, the procedure assigns the name of the most recently generated temporary table to the _TEMPLAST_ macro variable.

You can use the TABLE statement to switch the active table to the temporary table and perform analyses. Make sure that the statement that generated the temporary table is separated from the next statement with a RUN statement. Otherwise, you receive an error that the table specified in the TABLE statement does not exist. The temporary table does not exist at parse time, it is created at run time when the statement is executed.

  table lasr.&_templast_
    tableinfo; 
    columninfo;
    fetch / from=1 to=20 format;
    summary;
quit;

If the input table is not partitioned, you can still use temporary tables with the SUMMARY and CROSSTAB statements, provided that you perform a group-by analysis. The temporary table that is created by the server is automatically partitioned by the group-by variables. This potentially involves a redistribution of the groups in the result set to transfer all the result records for a particular group to the same worker node.

You can use temporary numeric variables in a table. For example, if a table has variables that are named x1, x2, and x3, you can calculate the summary statistics for variable d1 = x1 + x2 / 3*x3. One way is to declare d1 as a temporary variable of the table (with data set options for the input table). You can use the temporary variables (temporary for the duration of each statement) with DATA step expression scripts.

proc imstat data=lasrlib.table1(array=(d,1));
    summary d1 x1-x3 / tempnames=d1 tempexpress="d1 = x1 + x2 / 3*x3;";
run;
    summary d1 / tempnames=d1 tempexpress="d1 = mean(x1, x2);";
quit;

Because the temporary variable exists for the duration of the statement, it can be reused in subsequent statements. The second SUMMARY statement uses the d1 variable with a different expression.