Example: Using TEST with WAIT - Teradata Vantage

This example uses TEST with WAIT. The program asynchronously spawns two update requests, req_1 and req_2, respectively, then waits until both req_1 and req_2 have completed before proceeding.TEST statements monitor SQLCODE to determine when both req_1 and req_2 have returned successful completion codes (SQLCODE = 0) before continuing with the rest of the main program.

If either request has not completed (SQLCODE = -651), then the wait continues.

When both statements have completed, then the main program continues processing.

The non-SQL statements are pseudocode that show how the WAIT and TEST SQL statements may fit into a host main program.

        ...
        EXEC-SQL
          ASYNC req_1
          UPDATE table_a
          SET a = :a;
        EXEC-SQL
          ASYNC req_2
          UPDATE table_b
          SET b = :b;
        ...
    100 EXEC-SQL
          WAIT req_1, req_2 COMPLETION;
        ...
        EXEC-SQL
          TEST req_1 COMPLETION;
       IF SQLCODE = -651 THEN GOTO 100
       IF SQLCODE = 0 THEN CONTINUE
        EXEC-SQL
          TEST req_2 COMPLETION;
       IF SQLCODE = -651 THEN GOTO 100
       IF SQLCODE = 0 THEN CONTINUE
        ...