Activation group states
An activation group is in one of three states at any time.
The three states are:
- Connectable and connected
- Unconnectable and connected
- Connectable and unconnected
The following figure shows the state transitions: Figure 1. Remote unit of work activation group connection state transition
The initial state of an activation group is connectable and connected. The application server to which the activation group is connected is determined by the RDB parameter on the CRTSQLxxx and STRSQL commands and might involve an implicit CONNECT operation. An implicit CONNECT operation cannot occur if an implicit or explicit CONNECT operation has already successfully or unsuccessfully occurred. Thus, an activation group cannot be implicitly connected to an application server more than once.
- Connectable and connected state
An activation group is connected to an application server and CONNECT statements can be executed. The activation group enters this state when it completes a rollback or successful commit from the unconnectable and connected state, or a CONNECT statement is successfully executed from the connectable and unconnected state. - Unconnectable and connected state
An activation group is connected to an application server, but a CONNECT statement cannot be successfully executed to change application servers. The activation group enters this state from the connectable and connected state when it executes any SQL statement other than CONNECT, COMMIT, or ROLLBACK. - Connectable and unconnected state
An activation group is not connected to an application server. The only SQL statement that can be executed is CONNECT.