Loosing 5 in 14000 granted connection --- Why??

Question

Hi:
I am currently working of a real high volume application that uses
WLS 5.1, WLS RMI JDBC Driver, Oracle DB 8i.
The deal is --- code looks right. Every connection that is opened is then closed
after doing all the DB specific stuff. No issues on that front. In a low volume
environment no connections are lost. However in production environment, with the
number of users scaling up the connections gets lost!.
Today we lost about 5 connection out of 14,000 granted connection. The pool size
is 200 and we are hovering about 130 lost connections. The server will then need
a reboot at the end of day to refresh the pools.
Any ideas would would be great!
Thanks
~v

Answer 1

Thanks Joseph --- Seems to me like the problem is clearly at the application end
of the spectrum. Will try to troubleshoot this and if I run into wall. I will
come back.
Thanks
Vish
Joseph Weinstein <[email protected]> wrote:
>
>
Vish Krishnan wrote:
Command line utility to reset the pool. Thats neat. But there areother org issues
like a "Green" sys-admin. I bet they wont budge beyond CRON reboot-- shrug. (But
I will sure get the point across)so be it.
Well... If you are hinting at a Database Connection object being storedas a
member variable in a DAO I say yes. Otherwise
The application as such is "supposed" to be stateless. With a useraction being
atomic. But then there are some "things" cached for "perf" reasons.Then it sounds like a problem with DAO, unless you can be sure the DAO
objects
are thread-safe, and that they/you close and/or nullify their connection
references by
the end of each invocation.
The code that is used to get db connection is
java.sql.Driver myDriver =
(java.sql.Driver) Class.forName(DBDRIVER).newInstance();
String url = DBURL;
java.util.Properties props = new java.util.Properties();
props.put("weblogic.server.url", SERVERURL);
props.put("weblogic.jdbc.datasource",DBSOURCE);
myCon = myDriver.connect(url, props);What are the DBDRIVER and DBURL strings?
I recommend:
DBDRIVER = "weblogic.jdbc.pool.Driver";
and DBURL = "jdbc:weblogic:pool:YOURPOOLNAME";
then
myConn = myDriver.connect(DBURL.null); // no props needed.
Actually there are three connection pools to three diff db. Two connpools seems
to be OK and they get the connection from DataSource (JDBC 2.0) butthen they
are low volume. The one who is loosing connection get the connectionby above
code.
that would prevent their being GC()'ed, and I can show you a way to
get
pool
connections more directly than from DataSources.HEY --- That would be a cool trick to know ;)Now, all you need is to verify for me that 'myConn' is a method variable,
not
a class or isntance variable, and that the call to myDriver.connect()
is in
a try block whose finally block closes myConn as the first thing, then
we should
be good.
Note that if your JDBC use is supposed to be stateless, then you should
never need
any more connections in a pool than you have execute-threads in the server.
Joe
Vish Krishnan
Joseph Weinstein <[email protected]> wrote:
Vish Krishnan wrote:
Unfortunately... A CRON Job seem to have favored out than openingup the console
and reseting the pool ;)Admin pool functions are available via command-line, using the weblogic.Admin
tool. This is suitable for cron.
The connections are used up by DAO classes, which are invoked basedon user action
from a controller servlet.Are these objects stateful, such that JDBC connections need to be
retained
beyond
an invocation of the controller servlet?
ITs 5.1SP11.Ok. This codeline has a finalize() method in pool connection objects,
which will
return abandoned pool connections to the pool when GC() reclaims them.
This
will certainly be slower than if they were closed correctly, but will
happen.
Show me the code you use for obtaining pool connections. If there'sa
bug in
the DataSource/RMI driver that retains references to pool connections,
then
that would prevent their being GC()'ed, and I can show you a way toget
pool
connections more directly than from DataSources.
Joe
Our testing env has only low volume user base. Unfortunately at
this
moment we
dont have state of the art load testing tool to mimic thousands
of
virtual users
and therefore rendering our team with little ideas in dev/testing
env.
So I am
fishing around news groups for clues?
Any help would be really be helpful ;)
Joseph Weinstein <[email protected]> wrote:
Vish Krishnan wrote:
Hi:
I am currently working of a real high volume application that
uses
WLS 5.1, WLS RMI JDBC Driver, Oracle DB 8i.
The deal is --- code looks right. Every connection that is openedis
then closed
after doing all the DB specific stuff. No issues on that front.
In
a low volume
environment no connections are lost. However in production environment,with the
number of users scaling up the connections gets lost!.
Today we lost about 5 connection out of 14,000 granted connection.The pool size
is 200 and we are hovering about 130 lost connections. The server
will
then need
a reboot at the end of day to refresh the pools.
Any ideas would would be great!Some things:
1 - A reboot shouldn't be necessary, just a call to admin to resetthe
pool.
2 - How/where are the connections used? In servlets/JSPs or EJBs?
3 - What version of 5.1?
Joe
Thanks
~v