Re: Remote database

Karsten Farrell <kfarrell_at_belgariad.com> wrote in message news:<MPG.18b2cf996c911e0f989698_at_news.la.sbcglobal.net>...
> hillar_at_medisoft.ee said...
> > Hello,
> > how to check remote datatabase is up or down,
> > link exist & if remote database is up all work fine,
> > but if remote database is down i have big timeout &
> > some meory problems
> > Hill
> >
>
> Depends on your client's o/s, which you didn't supply. If your client is
> unix-like, you can wrap the following in a shell script and grep the
> return string.
>
> You can issue a "lsnrctl services" and check the return to see if you
> have a dispatcher or dedicated server with established connections. This
> should be pretty quick, since you don't have to wait for a database
> timeout and the listener always knows when the database goes up/down.

I've seen some listeners be pretty slow on the uptake, so to speak. For example, the db comes up and it takes a minute or two for the service to show up. So you'd quickly find out the wrong info!

>
> You can always issue a "select * from dual_at_remotedb" and get back
> success/failure. Of course, if the database is down, you'll have to wait
> for a timeout.

Network operations are flaky by nature, so you pretty much have to wait, unless you have an app that requires a quick network, which would probably be a design error...

jg

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