Re: WebLogic, Oracle JDBC related

Good discussion.

We have exactly the same setup. You are correct Suzy. However would like to confirm that WL manages the connection pools and like Suzy has mentioned is how they are set.

Before starting the application a minimum number of connection pools are defined for weblogic and when the application starts one will notice that many connections made to Oracle. Now these minimum connections (used or not used) remain attached to the database for the life of the application (at least that is what we are noticing).

Kriti, I am not sure what JDBC driver you are using. Thick or thin? if you are using the JDBC thick driver you have some control, like you can enable TNS tracing on both the client and database server side and look at the traffic. Also there is another great tool (really good) called Velocitop (i think that is how its spelt) that is placed in front of the JDBC connection on the app server side. Using this tool you could clearly measure and drill down various aspects of the network traffic, initiator, requests, waits, commits, rollbacks etc.

Now one hurdle, is with transaction management, since WL logic takes care of cleaning up transactions, the developers do not explicitly disconnect or complete a connection for reusability. This is bad, because while we are moving away from WL, the new application server will not do this automatic closing of connections hence these connections are being consumed pretty quickly.

Long, connections pools have a similar behavior as MTS or Shared Servers (in Oracle 9i) Basically to share connections to the database.

Regards

Murali

Reply-To: ORACLE-L_at_fatcity.com
To: Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com> Date: Thu, 27 Jun 2002 18:53:18 -0800

Again, I'm a little rusty on WL, it's been awhile (4.5) and don't have access to a current working environment. So, someone please correct where I'm wrong...

The WL server does manage the connection pool. The WL server creates a pool of database connections at server startup (initialCapacity). When the app code makes a database call, it accesses a connection from the pool then releases it back to the pool when the database call completes. IIRC, there are Java classes for accessing & releasing connections from the pool.

If all initialCapacity connections in the pool are in-use, WL server allocates more connections in the pool as needed (capacityIncrement), up to and not exceeding maxCapacity. There are other parameters that control the pool, which Bill Pass mentions in his reply.

Suzy

Long.Nguyen_at_csiro.au wrote:
>
> Suzy,
>
> You said "The app java code should be managing the allocation and release
of
> connections within the pool". Do not know anything about connection pool,
so this might be a naive question: It seems to me that it is not a good set up if the applications have to do the pool managing themselved; why can't WL do the pool
> managing itself?
>
> Long
>
> -----Original Message-----
> Sent: Friday, 28 June 2002 3:03 AM
> To: Multiple recipients of list ORACLE-L
>
> I'm really rusty on this topic, but...
>
> Connection pooling is configured in weblogic.properties, and would look
> something like this:
>
> weblogic.jdbc.connectionPool.xxxxxxxx=\
> url=jdbc:oracle:thin:@hostname:port:db_name,\
> driver=oracle.jdbc.driver.OracleDriver,\
> initialCapacity=2,\
> maxCapacity=10,\
> capacityIncrement=1,\
> props=user=xxxx;password=xxxx;weblogic.codeset=UTF-8
>
> Tuning of parameters initialCapacity, maxCapacity, capacityIncrement are
> key. Here's some info for WL 4.5 (you might instead need to search for
> 6.x docs):
>
> http://www.weblogic.com/docs45/admindocs/properties.html#conpools
> http://www.weblogic.com/docs45/techdeploy/jdbcperf.html
>
> The app java code should be managing the allocation and release of
> connections within the pool. It might be this isn't being done properly
> within the vendor's code. Or maybe initialCapacity isn't set high
> enough for the application, which is allocated when WL is initially
> started, then incremented as-needed as set by capacityIncrement.
>
> Checking v$session for how many connections are created when WL is
> started, then monitoring it during application use might help lead you
> to an answer.
>
> Suzy
>
> "Deshpande, Kirti" wrote:
> >
> > We are in the process of rolling out a Web Appl that uses BEA WebLogic
and
> > Oracle JDBC, thin driver calls to connect to database. These are
dedicated
> > connections (No MTS). The listener is overwhelmed with connection
requests
> > that at times reach 250+ per second. The 'preferred vendor' is blaming
it on
> > the limitation of the Listener, that is not capable of handling this
load.
> >
> > I suspect this fine piece of software is not using JDBC connection
pooling.
> > Is there any way to find out if that's indeed the case? I am not
involved in
> > this project, and may not get access to the Appl Code. A co-worker is
asking
> > me all kinds of questions about Listener problems. The Vendor is
suggesting
> > to increase the QueueSize for the listener. They have already created
> > multiple listeners in vain.
> >
> > I think the Appl code is to blame. I do not know much about Java/EJB
etc..
> > but my hunch is that this EJB container stuff does not smell good. For
all I
> > know it could be making a db connection for every single thing and
> > disconnecting.
> >
> > Anyone dealt with similar issues?
> > All tips are welcome and appreciated.
> >
> > All right, the preferred vendor is AMDOCS. Anyone running any of their
Web
> > Applications? If so, can you please contact me off-list?
> >
> > Thanks.
> >
> > - Kirti
> > --
> > Please see the official ORACLE-L FAQ: http://www.orafaq.com
> > --
> > Author: Deshpande, Kirti
> > INET: kirti.deshpande_at_verizon.com
> >
> > Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051
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> Please see the official ORACLE-L FAQ: http://www.orafaq.com
> --
> Author: Suzy Vordos
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> Author:
> INET: Long.Nguyen_at_csiro.au
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--
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--
Author: Suzy Vordos
   INET: lvordos_at_qwest.com

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Murali Vallath
Oracle Certified DBA
http://www8.ewebcity.com/muralivallath/
http://www.summerksyus.com/


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-- 
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-- 
Author: Murali Vallath
  INET: murali_vallath_at_hotmail.com

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