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From johannes.fi...@fwd.at
Subject RE: JNDI connection pooling maximum connections exceeded - Tracking?
Date Fri, 04 Apr 2003 06:05:46 GMT
Hi Mike

It seems poolman is currently considerably exceeding the functionality of 
dbcp.

Can you post a link where I can find it?
Is it in general preferable to use poolman instead of dbcp as dbcp 
provides only a small set of functionality for production sites?

thx alot
Johannes




"mike jackson" <mjackson@cdi-hq.com> 
04.04.2003 01:47
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Subject
RE: JNDI connection pooling maximum connections exceeded - Tracking?






I set the upper limit as a soft limit (I'm using poolman, not dbcp).
Since the database doesn't seem to care when I exceed the limit (happens
rarely anyway) it hasn't been an issue as of yet. 

However, my old connection pool did have a hard limit.  What I ended up
doing at that point was blocking the request until a connection was
available.  I had an implementation of a counting semaphore to managing
the connection count.  So, to the user it just looked like the request
was taking a bit longer to process.  I'm typically in and out of the
database fairly quickly, so it didn't seem to be much of an issue. 

Occasionally connections would get lost, which would eventually lock the
pool, so I switched to poolman.  With poolman I can watch the connection
pool metrics, at least to the level of being able to see the total count
and connections in use.  The log will typically tell me when connections
have been lost or closed due to expiring their time to live.

--mikej
-=-----
mike jackson
mjackson@cdi-hq.com

-----Original Message-----
From: johannes.fiala@fwd.at [mailto:johannes.fiala@fwd.at] 
Sent: Thursday, April 03, 2003 12:07 PM
To: Tomcat Users List
Subject: JNDI connection pooling maximum connections exceeded -
Tracking?

HI there,

I'd like to know what professional developers do when the maximum number

of connection in a connection pool has been reached.
What should be done with requests that don't get a connection?
Should the max connection set to a very high number hoping that the
number 
of requests served concurrently will be lower? Is it a way to set to -1,

thus no limit is active?

I think no web application wants to print out "maximum number of 
connections exceeded. please try again later".
I for myself would prefer to have a debug log or so to track if the
number 
of concurrent connection has some peaks to at least know what the
current 
maximum of concurrent connections is.

I wonder why this is not part of the dbcp.commons package. Shouldn't 
connection tracking become a part of it?

thx alot
Johannes



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