This topic describes the various "stopped" states of the WebSphere® MQ link and its sender and receiver channels, on a service integration bus.
Stopping a WebSphere MQ link sender stops only the WebSphere MQ link sender channel. (However, when the WebSphere MQ link sender channel is stopped, it communicates with the receiver channel in the WebSphere MQ network to say it is stopping, with the result that the receiver channel on WebSphere MQ stops and goes into inactive state.)
If a currently RUNNING WebSphere MQ link sender channel is stopped in state STOPPED, it goes to STOPPED state.
If a currently RUNNING WebSphere MQ link sender channel is stopped in state INACTIVE, it goes to STANDBY state.
Stopping a WebSphere MQ link receiver stops all receiver channel connections for that receiver.
If a currently RUNNING WebSphere MQ link receiver channel is stopped in state STOPPED, it goes to STOPPED state. The sender channel in the WebSphere MQ network will notice, either when it tries to next send some data, or when its heartbeat interval is reached and it tries to send a heartbeat flow, or when its disconnect interval expires and it attempts to close the session, that the WebSphere MQ link receiver in the service integration bus is in STOPPING state and itself stop and then enter a state of RETRYING. The WebSphere MQ link receiver will then go to STOPPED state, so preventing a sender channel in the WebSphere MQ network from establishing a session.
If a sender channel in the WebSphere MQ network is started while a WebSphere MQ link receiver channel in a service integration bus is in STOPPED state, the request fails with an error indicating that the WebSphere MQ link receiver channel is not available.
If a currently RUNNING WebSphere MQ link receiver channel is stopped in state INACTIVE, it goes to STOPPING state. The sender channel in the WebSphere MQ network will notice, either when it tries to next send some data, or when its heartbeat interval is reached and it tries to send a heartbeat flow, or when its disconnect interval expires and it attempts to close the session, that the WebSphere MQ link receiver is in STOPPING state and itself stop and then enter a state of RETRYING. The WebSphere MQ link receiver will then go to INACTIVE state. The RETRYING sender channel in the WebSphere MQ network will then establish a session with the WebSphere MQ link receiver channel, at which point both channels will go to RUNNING state.
Stopping a WebSphere MQ link receiver channel connection stops only that connection. Individual connections can only be stopped in target state INACTIVE.
When an active WebSphere MQ link receiver channel connection is stopped, the connection goes to a state of STOPPING. The sender channel in the WebSphere MQ network will notice, either when it tries to next send some data, or when its heartbeat interval is reached and it tries to send a heartbeat flow, or when its disconnect interval expires and it attempts to close the session, that the WebSphere MQ link receiver is in STOPPING state and itself stop and then enter a state of RETRYING.
The MODE has an effect on the stopping of channels.
In the case of a WebSphere MQ link sender channel, the link sender goes to STANDBY or STOPPED state (depending on the stop state specified), this can occur either when it reaches the end of the current batch, or when it reaches a heartbeat interval.
In the case of a WebSphere MQ link receiver, the link receiver goes to STOPPING state and then to INACTIVE or STOPPED state (depending on the stop state specified) when the sender in the WebSphere MQ network next attempts to communicate with it. Though, if a WebSphere MQ link receiver channel goes INACTIVE and the sender channel in the WebSphere MQ network goes to RETRYING, then as soon as a session is reestablished, both ends will go to RUNNING state.
In the case of a WebSphere MQ link sender channel, the WebSphere MQ link sender goes to STANDBY or STOPPED state (depending on the stop state specified).
In the case of a WebSphere MQ link receiver, the WebSphere MQ link receiver goes to INACTIVE or STOPPED state (depending on the stop state specified). When the sender channel in the WebSphere MQ network next tries to communicate with the WebSphere MQ link receiver, it will either enter a state of RETRYING and reestablish a session with the WebSphere MQ link receiver, or go to a STOPPED state.
WebSphere MQ link sender channels can go to INDOUBT state (as can sender channels in a WebSphere MQ network). WebSphere MQ link receiver channels do not go to INDOUBT state.
While sending a batch of persistent messages, a WebSphere MQ link sender channel goes to a state of INDOUBT. When it commits the batch, it sends a commit request to the partner and waits for confirmation. When the partner sends a confirmation, the batch is finally committed and the sender channel is no longer in INDOUBT state. If the partner fails to send a confirmation flow, then the sender channel will remain in INDOUBT state.
INDOUBT batches can be COMMITTED or ROLLED back from the Saved Status panel for WebSphere MQ link sender channels.