The COMMIT operation tells the system that you have completed a group of changes to the files under commitment control. The ROLBK operation eliminates the current group of changes to the files under commitment control. For information on how to specify these operation codes and what each operation does, see the IBM Rational Development Studio for i: ILE RPG Reference.
If the system fails, it implicitly issues a ROLBK operation. You can check the identity of the last successfully completed group of changes using the label you specify in factor 1 of the COMMIT operation code, and the notify-object you specify on the STRCMTCTL command.
At the end of an activation group or job, or when you issue the ENDCMTCTL command, the IBM i system issues an implicit ROLBK, which eliminates any changes since the last ROLBK or COMMIT operation that you issued. To ensure that all your file operations have effect, issue a COMMIT operation before ending an activation group or job operating under commitment control.
The OPEN operation permits input and output operations to be made to a file and the CLOSE operation stops input and output operations from being made to a file. However, the OPEN and CLOSE operations do not affect the COMMIT and ROLBK operations. A COMMIT or ROLBK operation affects a file, even after the file has been closed. For example, your program may include the following steps:
The changes made at step 3 are rolled back by the ROLBK operation at step 5, even though the file has been closed at step 4. The ROLBK operation could be issued from another program in the same activation group or job.
A program does not have to operate all its files under commitment control, and to do so may adversely affect performance. The COMMIT and ROLBK operations have no effect on files that are not under commitment control.