Hi
I wrote this email a few days ago but it seems not to be distributed by the
mailing
list, Andy.
----- Original Message -----
From: Aaron Mulder <[EMAIL PROTECTED]>
To: jBoss Developer <[EMAIL PROTECTED]>
Sent: Saturday, September 02, 2000 8:18 PM
Subject: [jBoss-Dev] Two More Thoughts
> Second, I don't think the "listener" approach to JMX MBean
> ordering will work. Consider that the auto-deployer must deploy after
> *all* databases have started. If it just listens for the database pool
> bean (assuming it can listen on a class rather than instance, so it won't
> have to know *which* pools are there), it may load after one of 10
> databases, which would still cause problems. If we load all the instances
> for a class at once (all pools, etc.) and it waits for that to complete,
> it will never start if there are no pools. There may - may - be some way
> around this if we let each MBean look at the entire list of MBeans before
> it decides which ones to listen for, but this is getting pretty nasty...
> I think it would be simpler for each MBean to list all the MBean
> classes it depends on, and then load all the instances of those (where
> available) first.
I think I see you point but is it always necessary that *all* databases must
be started before the auto-deployer can run?
What do you do when the a DB cannot be reached (PostgreSQL is down)?
Will you wait till this DB comes up and then start the auto-deployer?
What if this DB is not used?
I think the problem is not that DBs should be started when the auto-deployer
runs but that the auto-deployer or its started EJBs should be able to try
till
the DB is up and running.
I do not think that the auto-deployer depends on the DBs but the EJBs
started
by the auto-deployer do (you can have EJBs connecting to legacy systems
which is out of the control of the auto-deployer or the jBoss startup
procedure).
I brought up the idea of the JMX listeners but I go along with Richard that
the
JMX Relationship Service is maybe a better solution becaus it makes the
dependency definition easier for the user because I think the dependencies
can change over time.
Have fun
Mad Andy
>
> Aaron
>
>
