[ebxmlms-general] Connectionpooling and transactions. was: Problems after lost connection to database

[Ronald v. K. <rtv...@xs...>]

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 datab=
ase and a filesystem.
This makes it almost impossible to use the default JTA for this, which wo=
uld 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 pers=
istency 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:
> 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:
>
>> Yes, why not include for example Jakarta Commons DBCP?
>>
>> At 2005-06-27 09:29, you wrote:
>>
>>> 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
>>>
>>>> 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:
>>>>
>>>>> 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 Sourc=
e)
>>>>>     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.
>>>>>
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