Optimized Access Cycle of Silk Performer

To perform a SQL command in a Silk Performer program, all you have to do is to call the SQL command at the position in the program where you want to execute it. Silk Performer manages all operations (ODBC function calls) necessary to process the SQL command for you. By default, Silk Performer uses an optimized access cycle (calling only ODBC functions that are absolutely necessary to perform the SQL commands).

Silk Performeruses the following access cycle of ODBC function calls:

The connection to the database is established once at the beginning of a simulation and is closed at the end of a simulation. Also, all cursors/statement handles used in a simulation are allocated at the beginning of the simulation and are freed at the end of the simulation. At the end of a transaction Silk Performer automatically performs a commit. A SQL command is prepared only if it is not already active on the related cursor (the related cursor is the cursor that preceded the call of the SQL statement).

A SQL command is active on a cursor if:

• it already has been prepared on the same cursor

(and)

• no other SQL command has been prepared and executed on the same cursor in the meantime.

(and)

• there was no commit or rollback statement between the current call of the SQL command and the last call

(or)

• there was a commit or a rollback and the two options of the DBMS are set to SQL_CB_CLOSE or SQL_CB_PRESERVE.
  • SQL_CURSOR_COMMIT_BEHAVIOR (and)
  • SQL_CURSOR_ROLLBACK_BEHAVIOR

Silk Performer is designed to remove ODBC overhead that could skew actual results on the database under test.