MQSeries.net :: View topic - Simultaneous Client connections to multiple Queue Managers?

mcmags34

MQ Guys,

This issue has been posted in many different flavors, so I apologize if it seems like old news. However, I think this situation is slightly unique, so I'll thank you in advance for your patience in reading this!

Can an MQSeries Client (5.2.1 for NT) connect to multiple Queue Managers on multiple servers (AIX) at the SAME TIME?

Example: I have an MQ Client. It actually hosts a web page that allows users to send messages to different Queues (possibly residing on different Queue Managers). If I only had to worry about it conencting to a single Queue Manager, life would be simple and good. I've been able to get this to work consistently with either MQSERVER or MQCHLTAB/MQCHLLIB environment variables. No surprises here.

Where things get a bit tough is the scenario where this single MQ Client machine wants to issue MQCONN calls to different Queue Managers residing on different servers. Clearly, MQSERVER is not going to work here. I don't see how the channel files would work either, since you can only point to one MQCHLTAB at a time, which only has Channel definitions from a single Queue Manager (am I right?).

Knowing these facts, I turned to the MQCNO structure, which is supposed to override all of this environment nonsense and just connect to the channel I specify using the connection name and protocol that I want at that particular moment in time. Just to be sure that these structure settings would take precedence, I blew away my MQ environment variables and rebooted.

When I try to issue MQCONN calls now, they work for connections to Queue Manager A. However, when I try one to Queue Manager B (on a different machine from A), I get a 2058 (QM name not valid). I issue MQDISC calls each time, but it's like the Client is still connected to A and therefore is looking for a Queue Manager named B over the previously established connection. Then, all of a sudden, the connection to B starts working and the one to A fails. The RC each time is 2058.

Damn, this is long! Sorry.

Am I crazy for trying this type of stuff? Does anyone else have this need? What is really interesting is that I tried the same setup on a machine with the full-blown MQ Server installed (but still using the client API from the application), and it works fine most of the time! It seems to have no trouble maintaining multiple connections. Does this mean that I need to have a Queue Manager on any machine from which I want to host MQ-enabled web pages?

One other note: The web pages run under IIS and call a VB ActiveX DLL that (carefully and cleanly) handles the MQ API calls. My next test is going to be to try referencing this DLL from an EXE to see if IIS might be contributing to the instability.

Any thoughts or considerations? Thanks so much for sticking with me!

Chris