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From: Shaun Farrugia <sfarrugia@fry.com>
To: Tomcat Users List <users@tomcat.apache.org>
Date: Wed, 1 Apr 2009 13:12:08 -0400
Subject: RE: Connection Pooling questions
Thread-Topic: Connection Pooling questions
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I ended up testing this based on the following

Tomcat 5.5.27, JTDS 1.2, Abandoned Logging and Return set to 30 seconds and=
 true.

Test A) Open connection, open Prepared Statement, Open Result set, Close Co=
nnection

Test B) Open Connection, open prepared Statement, open resultset. Didn't cl=
ose anything.


Test A Resulted in statements and result sets not affecting or throwing err=
ors on the client side.  Didn't check to see if cursors were open in the db

Test B Resulted in Abandoned Pool thrown after waiting 30 seconds and execu=
ting the test again.


-----Original Message-----
From: Shaun Farrugia [mailto:sfarrugia@fry.com]=20
Sent: Wednesday, April 01, 2009 11:00 AM
To: Tomcat Users List
Subject: RE: Connection Pooling questions

Sweet,

I set up a test.jsp page that will Connection.close() without rs.close() an=
d ps.close().  Will let you know the results..

And I know you answered this before but I have to ask again.

Tomcat is using it's own version of DBCP (based on properties files)  Are t=
here any changes to DBCP other than package moves?  Can I utilize the DBCP =
source package and expect that it's the same code tomcat is using?


-----Original Message-----
From: Caldarale, Charles R [mailto:Chuck.Caldarale@unisys.com]=20
Sent: Wednesday, April 01, 2009 10:47 AM
To: Tomcat Users List
Subject: RE: Connection Pooling questions

> From: Shaun Farrugia [mailto:sfarrugia@fry.com]
> Subject: RE: Connection Pooling questions
>=20
> What happens when the statement isn't closed but the=20
> connection is returned to the pool?

The connection object your code sees isn't the real connection; it's a wrap=
per created by the pool to control access to the real thing.  Likewise, the=
 ResultSet, Statement, PreparedStatement, etc., objects visible to the weba=
pp are also wrappers around the real objects.  Using these, the pool knows =
if the real connection has been cleaned up properly; the pool won't reuse t=
he connection until it is has returned to an idle state.

> I have some code blocks that don't have a finally block=20
> to close the result set and prepared statement.  If an=20
> exception happens the statement and the result set stay
> open but the connection gets returned to the pool.

A brief scan of the code in commons-dbcp indicates that when a Connection.c=
lose() is done, an attempt is made to close the associated Statement and Re=
sultSet objects.  Some experimentation (which I don't have time for right n=
ow) would make me more comfortable with that observation.

 - Chuck


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