Bob
I believe Oracle uses 1 process for each connection by default unless
you've set up Oracle to use the MTS dispatcher.

And also by default 50 is the default max process for Oracle.
You can control this file by editing your INIT*.ORA file typically found
in %ORACLE_HOME%\<YourSID>\pfile\init*.ora and look for the 
entry 

PROCESSES=100

BTW, you also need to restart your Oracle server to pick up the new value.

Since connections are pooled (Don't know much about Turbine Pooling) but
in theory, if you app uses connection wisely, you shouldn't need too many 'physical' 
connections.  BUt that entirely depends on your concurrent load and length
of time a connection is used by a thread in your app.  You need to load test your
app to find the right number.

Also beware that Oracle also limits 300 open cursors by default.  This
is another area where most people also run into trouble.  You can
change this param in your init*.ora file as well.  If you need a large
number of connections, chances are you probl. will run into this limit as well.

open_cursors = 300




-----Original Message-----
From: Bob Swerdlow [mailto:[EMAIL PROTECTED]]
Sent: Wednesday, March 13, 2002 10:06 AM
To: [EMAIL PROTECTED]
Subject: DB Pooling and Processes


Hi, y'all -

Is there documentation somewhere about how to set up Oracle with Turbine DB
Pooling?

We ran into a problem recently where we were getting "cannot get connection"
errors.  I found that our TurbineProperties.Resources had:

    # The number of database connections to cache per ConnectionPool
    # instance (specified per database).
    database.default.maxConnections=3

Since the failure happend when our code was setting up 4 connections, I knew
I had to change this.  After a bit of web-snooping, I changed it to 100.

Now we are getting this error:
    ORA-00020: maximum number of processes (50) exceeded

This actually happened after reloading the project a few times.

So my questions are:
  1. What is an appropriate value for database.default.maxConnections?  This
will be a public web site with many concurrent users retrieving pages that
will access the database
  2. Do I need to coordinate the number of connections with the number of
Oracle processes?  How do I control this in Oracle?
  3. Should reloading the project release all of the connections?  It does
not seem to have done so, however, when I restarted Tomcat, those processes
seemed to go away.
  4. What else should I worry about?

Thanks for your help!

Bob Swerdlow
Chief Operating Officer
Transpose, LLC
[EMAIL PROTECTED]






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