Two-Phase Commit Processing › Two-Phase Commit within CA IDMS › Transaction Outcomes

Transaction Outcomes

Transaction Outcomes

Fundamentally, a distributed transaction can have only one of the following three outcomes: all changes were committed, all changes were backed out, or some changes were committed while others were backed out. However, it is useful to support variations of these especially as interim results of individual Prepare and Commit requests.

CA IDMS recognizes the following outcomes:

• OK - The request is complete and the transaction's changes have been committed.
• FORGET - The request is complete, but no changes were committed since none were made (that is, this is a read-only transaction).
• OK_PENDING - The request is not yet complete, but changes have been or will be committed.
• BACKOUT - The request is complete but changes have been backed out.
• BACKOUT_PENDING - The request is not yet complete, but changes have been or will be backed out.
• HC - The request is complete, and the transaction's changes have been heuristically committed.
• HR - The request is complete, but the transaction's changes have been heuristically backed out.
• HM - The request is complete, but some changes have been committed while others have been backed out.

Heuristic Outcomes

Heuristic outcomes are the result of a commit or backout decision made by a participant rather than a coordinator. The use of DCMT VARY DISTRIBUTED TRANSACTION to force an InDoubt transaction to commit or back out results in a heuristic outcome.