Re: Issues when updating running apps?

[Greg_Swift aotx uscourts gov]

> I apologize for insisting on this matter, but so far I haven't been able
> to find info on this anywhere. I've looked at tomcat's and openoffice's
> spec files as examples of packaged java apps, but it doesn't seem they
> take any sort of precaution when updating. Is it really not an issue if
> the app happens to be running at the time?

In my experience I don't know that I've found a single web app that seems
to be overly concerned with this process inside the rpms.  We have some
internal java web apps, and I believe they just have "turn off x and y
services" listed in the update docs we distribute.

> As for updating a database schema accessed by our app, I suppose we
> could add that logic to the app itself and have it check before it
> starts whether it should modify the database, but I find adding scripts
> in the RPM much easier and I'd prefer any problems with the
> modifications to come up the moment the update is applied and not
> whenever the app is next started.

Once again, I haven't seen many that addresses this issue.  Part of the
problem of including this inside the RPM is the db authentication method.
I believe most apps I've seen require you to install the RPM, and then run
either a schema import or update script.  I've thought about this on my own
though and have decided that I like the concept of my application being
aware of its own schema, and managing the changes to the db itself (i
realize that this can in and of itself be a bit of a nightmare, but then so
is making schema changes via package managers).  Remember, I haven't tried
implementing it.

> I'd really appreciate any comments you could give me on this, whether
> they are direct answers, indirect tips on how I could find this info, or
> kind advice to go RTFM (as long as you tell me which FM in particular
> that would be :) )

I was avoiding commenting on this because I didn't have any solid answers
for you, but at this point I guess opinion and conjecture is enough since
no one else has commented.

enjoy

-greg