TNS listener error even when database is up

Hello,
I'm trying to execute some non expensive queries against an Oracle 10g database.I get a listener error, even though the database is mounted and open.

Any suggestions on why this happens.

Previously, listener errors always have resulted from database being in non mount state etc, and so starting the database had solved the problems.

edit: the listener is fine as well when I see its status.
Thanks.

edit: this is the error code form the logs:

ORA-12519, TNS:no appropriate service handler found

post your tnsnames file and learn the interaction between a client a listener and a database

Post your Listener status and instance name.

Quote:

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Originally Posted by dereliction

Hello,
ORA-12519, TNS:no appropriate service handler found

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Can you see a service for your instance listed in the listener status?

Register your instance with the listener!

What OS? Is async-io on?

Hello folks!
After doing some digging on the internet, I found these articles to be useful:

http://forums.oracle.com/forums/thre...60226&tstart=0
(scroll down to the bottom of thread)

and,

http://www.mcse.ms/archive26-2006-2-2174494.html

The number of processes indeed go upto 150 during the day as I found out.
So, I increased the number of processes in init.ora from 50 to 200.This solution works fine ... atleast for now.

PS:

Do you know about the EMNO process? When Oracle spawns it, it shuts down the database and everyone is caught unawares and face listener errors.

Taken from Alert Log:
Starting background process EMN0
EMN0 started with pid=110, OS id=13601
Wed Jul 12 14:54:12 2006
Shutting down instance: further logons disabled
Wed Jul 12 14:54:12 2006
Stopping background process QMNC
Wed Jul 12 14:54:12 2006
Stopping background process CJQ0
Wed Jul 12 14:54:14 2006
Stopping background process MMNL
Wed Jul 12 14:54:14 2006
Stopping background process MMON
Wed Jul 12 14:54:14 2006
Shutting down instance (immediate)
License high water mark = 133
Wed Jul 12 14:54:14 2006


Does the high water mark got to do anything with it?
Thanks.