You want to do some maintenance on one of my queue managers, and want to stop work coming in to the queue manager, and restart work when the maintenance has finished – without causing operational problems.
Applications using reconnection support, can reconnect to an available queue manager. To stop an application connecting to a particular queue manager you need to stop the channel(s). STOP CHL(…) STATUS(STOPPED). An application using the channel will get notified, or reconnected. An application trying to connect, will fail, and go somewhere else.
If you have two channels, one for the web server clients, and a second channel for the server application on the queue manager, I dont think it matters which one you stop first.
- If you stop the client program, then the message will go to the server application, be processed and put on the reply queue. The client will not get the reply, as it has been switched.
- If you stop the server applications first, then the messages will accumulate on the server queue, until the server applications reconnect to the queue manager and process the queue.
In either case you can have orphaned messages on the reply to queue. You need a process to resolve these, or for non persistent message set a message expiry time.
Once you have done your maintenance work, use START CHL(…) for the server channel, wait for a server to connect to the queue manager and then use START CHL(…) for the client channel. It may take minutes for a server application to connect to the queue manager.
Do it in this order as you want the server to be running before client applications put to the server queue, otherwise you will have to handle time out situations from the application.