RE: [ebxmlms-general] Connectionpooling and transactions

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Hmm... I missed the option to redirect file persistence to a database. =
I'll have a look. With 'still it is not transaction-aware' you mean that =
the filepersistence is not really transaction aware? There are some 'in =
vm-locking mechamisms' in there but no real commit/rollback etc. Would =
that be needed? Kind of difficult, but I'll see.

Ok, another question. I have a fairly clear picture of the front-end =
messageserver, messageservicehandler etc and how the command parsing =
works. In addition to that, I dug a little bit deeper into hermes again =
especially the DBTableManager classes etc. If it is possible I'd like to =
get some info on the architectural choices that were made to come to =
such a solution. It looks like it is some persistence mapping, for which =
there currently are very nice out-of-the-box solutions (think =
hibernate). IMVVHO (it is a very, very humble one) this would also be a =
nice change and would make it possible to support more databases.=20

I'll try to work something out which makes it possible to store messages =
in either a file or a database (configurable?)

-----Oorspronkelijk bericht-----
Van: ebx...@li... =
[mailto:ebx...@li...] Namens Patrick Yee
Verzonden: woensdag 6 juli 2005 4:02
Aan: ebx...@li...
Onderwerp: Re: [ebxmlms-general] Connectionpooling and transactions. =
was: Problems after lost connection to database

Now, Hermes supports a custom way (API) to redirect the file persistence =

to database. However, still it is not transaction-aware. So we may need=20
to modify that API as well. What do you think?
Regards, -Patrick

Ronald van Kuijk wrote:

>Sounds interesting. But with regard to this immediately a second =
question comes to mind. There is
>also a transactionmechanism in place which does a kind of xa over a =
database and a filesystem.
>This makes it almost impossible to use the default JTA for this, which =
would make the hermes core
>even smaller. For our company, storing the messages in a DB as a blob =
is not a problem since we
>require clustering and failover any way. It is in fact even a =
requirement unless there would be a
>JTA compatible filesystem persistency layer (JCA?)).
>
>Replacing the DBConnectionPool with a standard based solution can be =
done by me, since I've done
>it before and probably have the code somewhere. DBCP does not have to =
be provided then, since all
>servlet engines and j2ee servers contain one. But regarding the file =
persistency I'd like to get a
>response from more users since that is another issue.
>
>Comments?
>
>
>Patrick Yee probeerde me het volgende duidelijk te maken:
> =20
>
>>There is no strict reason for using our own implementation. So it =
would
>>be good to have some contribution to port Hermes to make use of other
>>database pool, like DBCP.
>>Regards, -Patrick
>>
>>Regards, -Patrick
>>
>>
>>Mattias J wrote:
>>
>>   =20
>>
>>>Yes, why not include for example Jakarta Commons DBCP?
>>>
>>>At 2005-06-27 09:29, you wrote:
>>>
>>>     =20
>>>
>>>>I guess the problem is that you have implemented your own
>>>>databasepool, without sophisticated recovery mechanism.
>>>>Our own application use javax.sql.DataSource, to get a connection. I
>>>>guess there is a recovery mechanism in that solution, as our own
>>>>application runs fine when the connection gets back.
>>>>Is there anyway to use javax.sql.DataSource instead of your
>>>>implementation of the connection pool? I guess my question is more =
to
>>>>why you are using your own implemtation, are you using some extra
>>>>stuff, I can't get from javax.sql.DataSource?
>>>>
>>>>Regards Kenneth
>>>>
>>>>       =20
>>>>
>>>>>From: Patrick Yee <kc...@ce...>
>>>>>To: ebx...@li...
>>>>>CC: tr...@ho...
>>>>>Subject: Re: [ebxmlms-general] Problems after lost connection to
>>>>>database
>>>>>Date: Sun, 26 Jun 2005 19:19:35 +0800
>>>>>
>>>>>We have not implemented a sophisticated recovery mechanism in the
>>>>>database connection pool. The only mechanism we have done is,
>>>>>whenever a connection is proved to be bad, we will not put it back
>>>>>to the connection pool. Actually there was a suggestion some time
>>>>>ago that we can do a "select *" on some tables before we use the
>>>>>pooled database connection. We think that will create certain
>>>>>performance issue, and so we shelved that idea. Of course, if you
>>>>>want it, you can just patch the database connection pool classes =
and
>>>>>implement any advanced recovery mechanism as you like. :-)
>>>>>Regards, -Patrick
>>>>>
>>>>>
>>>>>Kenneth Pedersen wrote:
>>>>>
>>>>>         =20
>>>>>
>>>>>>Hi
>>>>>>
>>>>>>If I loose the connection to my database for a short time
>>>>>>(1-2minutes), MSH do not operate properly afterwards.
>>>>>>
>>>>>>When the connection is lost this occurs in the MSH_client.log:
>>>>>>
>>>>>>2005-06-21 09:13:34,384 DEBUG [Thread-8]: =3D>
>>>>>>DbConnectionPool.getConnection
>>>>>>2005-06-21 09:13:34,384 DEBUG [Thread-8]: <=3D
>>>>>>DbConnectionPool.getConnection
>>>>>>2005-06-21 09:13:34,384 ERROR [Thread-8]: [10002] Unknown error
>>>>>>Exception: java.sql.SQLException
>>>>>>Message: I/O Error: Connection reset by peer: socket write error
>>>>>>2005-06-21 09:13:34,384 DEBUG [Thread-8]: =3D> =
Transaction.rollback
>>>>>>(txID: #2321)
>>>>>>2005-06-21 09:13:34,384 ERROR [Thread-8]: [10315] Cannot rollback
>>>>>>DB changes
>>>>>>Exception: java.sql.SQLException
>>>>>>Message: Invalid state, the Connection object is closed.
>>>>>>2005-06-21 09:13:34,384 DEBUG [Thread-8]: =3D>
>>>>>>DbConnectionPool.freeConnection
>>>>>>2005-06-21 09:13:34,384 DEBUG [Thread-8]: <=3D
>>>>>>DbConnectionPool.freeConnection
>>>>>>2005-06-21 09:13:34,384 DEBUG [Thread-8]: <=3D =
Transaction.rollback
>>>>>>2005-06-21 09:13:34,384 DEBUG [Thread-8]: =3D>
>>>>>>MessageServiceHandler.getNextUndeliveredMessage
>>>>>>2005-06-21 09:13:34,384 DEBUG [Thread-8]: =3D>
>>>>>>MessageServer.getUndeliveredMessages
>>>>>>2005-06-21 09:13:34,384 DEBUG [Thread-8]: =3D>
>>>>>>DbConnectionPool.getConnection
>>>>>>2005-06-21 09:13:34,384 DEBUG [Thread-8]: =3D>
>>>>>>DbConnectionPool.createConnection
>>>>>>2005-06-21 09:13:35,352 ERROR [Thread-8]: [10306] Cannot create DB
>>>>>>connection Exception: java.sql.SQLException Message: Network error
>>>>>>IOException: Connection refused: connect
>>>>>>2005-06-21 09:13:35,352 DEBUG [Thread-8]: =3D> =
Transaction.rollback
>>>>>>(txID: #2323)
>>>>>>2005-06-21 09:13:35,352 DEBUG [Thread-8]: <=3D =
Transaction.rollback
>>>>>>2005-06-21 09:13:35,352 DEBUG [Thread-8]: =3D>
>>>>>>MessageServiceHandler.getNextUndeliveredMessage
>>>>>>2005-06-21 09:13:35,352 DEBUG [Thread-8]: =3D>
>>>>>>MessageServer.getUndeliveredMessages
>>>>>>2005-06-21 09:13:35,352 DEBUG [Thread-8]: =3D>
>>>>>>DbConnectionPool.getConnection
>>>>>>2005-06-21 09:13:35,352 DEBUG [Thread-8]: =3D>
>>>>>>DbConnectionPool.createConnection
>>>>>>
>>>>>>
>>>>>>After the connection is restored MSH do not seem to get a proper
>>>>>>connection.
>>>>>>This occurs then in the MSH_Client.log:
>>>>>>
>>>>>>2005-06-21 09:13:42,384 ERROR [Thread-8]: [10306] Cannot create DB
>>>>>>connection
>>>>>>Exception: java.sql.SQLException Message: Network error
>>>>>>IOException: Connection refused: connect
>>>>>>2005-06-21 09:13:42,384 DEBUG [Thread-8]: =3D> =
Transaction.rollback
>>>>>>(txID: #2338)
>>>>>>2005-06-21 09:13:42,384 DEBUG [Thread-8]: <=3D =
Transaction.rollback
>>>>>>2005-06-21 09:13:42,384 DEBUG [Thread-8]: =3D>
>>>>>>MessageServiceHandler.getNextUndeliveredMessage
>>>>>>2005-06-21 09:13:42,384 DEBUG [Thread-8]: =3D>
>>>>>>MessageServer.getUndeliveredMessages
>>>>>>2005-06-21 09:13:42,384 DEBUG [Thread-8]: =3D>
>>>>>>DbConnectionPool.getConnection
>>>>>>2005-06-21 09:13:42,384 DEBUG [Thread-8]: =3D>
>>>>>>DbConnectionPool.createConnection
>>>>>>2005-06-21 09:13:43,384 ERROR [Thread-8]: [10306] Cannot create DB
>>>>>>connection
>>>>>>Exception: java.sql.SQLException
>>>>>>Message: Network error IOException: Connection refused: connect
>>>>>>
>>>>>>
>>>>>>
>>>>>>When i try to send a message through MSH i get this:
>>>>>>hk.hku.cecid.phoenix.message.handler.RequestException:
>>>>>>Failed to send query to MSH.
>>>>>> HTTP response code =3D 200
>>>>>> HTTP response message =3D OK
>>>>>>    at
>>>>>>hk.hku.cecid.phoenix.message.handler.Request.expectMapResponse(Unkn=
own
>>>>>>Source)
>>>>>>    at
>>>>>>hk.hku.cecid.phoenix.message.handler.Request.sendMessageServiceHand=
lerConfig(Unknown
>>>>>>Source)
>>>>>>    at
>>>>>>hk.hku.cecid.phoenix.message.handler.Request.register(Unknown =
Source)
>>>>>>    at hk.hku.cecid.phoenix.message.handler.Request.<init>(Unknown
>>>>>>Source)
>>>>>>    at hk.hku.cecid.phoenix.message.handler.Request.<init>(Unknown
>>>>>>Source)
>>>>>>    at
>>>>>>com.mysupply.ebxi.msh.MessageManager.sendMessage(MessageManager.jav=
a:149)
>>>>>>
>>>>>>
>>>>>>And of course I can not receive any messages through MSH either.
>>>>>>
>>>>>>Does anybody have the same problems, after a lost database
>>>>>>connection? The other part of my application that uses MSH, is
>>>>>>right back in action when the database connection is restored, but
>>>>>>not MSH.
>>>>>>
>>>>>>The app is running on jboss-4.0.1 (Tomcat 5.0.28), Java
>>>>>>jdk1.5.0_01. The database is Microsofts MSSQL 2000. The driver for
>>>>>>MSSQL is JTDS 1.0.
>>>>>>I have added this:
>>>>>><check-valid-connection-sql>select * from
>>>>>>some_table</check-valid-connection-sql>
>>>>>>to my datasource file: mssql-ds.xml which is deployed along with
>>>>>>msh.war.
>>>>>>
>>>>>>Everything is working fine, for days, until I loose the database
>>>>>>connection for a few minutes.
>>>>>>
>>>>>>_________________________________________________________________
>>>>>>Del din verden med MSN Spaces  http://spaces.msn.com
>>>>>>
>>>>>>
>>>>>>
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>>>>>         =20
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>
>
> =20
>

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