SQL TCL SYNCPOINT Statement

The SYNCPOINT statement is used in mainframe environments, particularly in transactional applications using CICS (Customer Information Control System). It functions similarly to a COMMIT statement but also manages transactions across multiple resources. SYNCPOINT ensures all changes are made permanent and other resources like files or queues, maintaining data integrity in complex applications involving DB2 and CICS.

In mainframe environments, the SYNCPOINT statement commits all changes made during a transaction to multiple resources, such as DB2 tables, VSAM files, and other CICS-managed resources. It is essential for:

• Finalizing transactions across different resources in a single operation.
• Ensuring data consistency across multiple resources by committing all changes or none.

Without SYNCPOINT, changes across resources may not be coordinated, leading to data inconsistencies in applications requiring multi-resource transactions.

Syntax -

SYNCPOINT;

• SYNCPOINT: Commits changes across all resources in the transaction.
• SYNCPOINT ROLLBACK: Reverts changes across all resources, effectively canceling the transaction.

Using SYNCPOINT Statement in a COBOL Program

In a COBOL-CICS program, SYNCPOINT is used after completing all operations to be committed. Executing SYNCPOINT finalizes changes across resources, ensuring data consistency. It is especially useful in applications where DB2 tables, VSAM files, and message queues are updated in a coordinated manner.

General Steps for Using SYNCPOINT in a COBOL-CICS Program:

1. EXEC CICS: Begin with the EXEC CICS block.
2. SYNCPOINT: Place SYNCPOINT after data modification statements across different resources.
3. Error Handling: Check EIBRESP (CICS response code) to confirm successful SYNCPOINT execution.

Examples - SYNCPOINT Statement in a COBOL-CICS Program

   * Step 1: Update Data in DB2 Table
	   EXEC SQL
		   UPDATE EMPLOYEE
		   SET SALARY = SALARY + 1000
		   WHERE JOB = 'MANAGER'
	   END-EXEC.
	   ...

   * Step 2: Write Data to VSAM File
	   EXEC CICS WRITE FILE('VSAMFILE')
		   FROM(WS-DATA-RECORD)
		   RESP(EIBRESP)
	   END-EXEC.
	   ...

   * Step 3: Commit Transaction Across Resources
	   EXEC CICS SYNCPOINT END-EXEC.

Error Handling for the SYNCPOINT Statement in a COBOL Program

In a COBOL-CICS program, error handling for the SYNCPOINT statement involves checking EIBRESP after execution:

• EIBRESP = 0: SYNCPOINT executed successfully, and changes are committed across all resources.
• EIBRESP < 0: Indicates an error, meaning the transaction was not committed. This may require retrying the transaction or performing a rollback.

Examples - Error Handling with SYNCPOINT Statement

       ...
   EXEC CICS SYNCPOINT END-EXEC.

   IF EIBRESP = 0
	   DISPLAY 'Transaction committed successfully.'
   ELSE
	   DISPLAY 'Error in SYNCPOINT operation: ' EIBRESP
   END-IF 
   STOP RUN.

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