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

Transaction States

Transaction State

Transaction state is an attribute of a distributed transaction that reflects its progress through a two-phase commit operation. The CA IDMS transaction manager assigns the following transaction states for this purpose:

• InReset - This is the initial state prior to the start of a commit or backout operation.
• InFlight - This state is assigned at the start of a two-phase commit operation and persists while the transaction manager is assessing the need for and the ability to proceed with the two-phase commit operation.
• InPrepare - This state is assigned when the transaction manager determines that a full two-phase protocol is needed to guarantee the integrity of a commit operation.
• LastAgent - This state is assigned by a coordinator's transaction manager when there is only a single participant and consequently a full two-phase protocol is not needed to guarantee the integrity of a commit operation.
• InDoubt - This state is assigned by a participant's transaction manager when it writes a DIND journal record for the transaction and persists until it receives a Commit or Backout directive from the coordinator.
• InCommit - This state is assigned when a DCOM journal record is written for the transaction and persists until all processing for the transaction is complete.
• InBackout - This state is assigned when it is determined that the outcome of the distributed transaction is BACKOUT and persists until all processing for the transaction is complete.
• Forgotten - This state is assigned when the two-phase commit operation is complete.

State Transitions

The following diagram illustrates the transitions that can occur from one state to another as a transaction proceeds through a two-phase commit operation.