Re: [ebxmlms-general] Problems after lost connection to database

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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]: => 
> DbConnectionPool.getConnection
> 2005-06-21 09:13:34,384 DEBUG [Thread-8]: <= 
> 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]: => 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]: => 
> DbConnectionPool.freeConnection
> 2005-06-21 09:13:34,384 DEBUG [Thread-8]: <= 
> DbConnectionPool.freeConnection
> 2005-06-21 09:13:34,384 DEBUG [Thread-8]: <= Transaction.rollback
> 2005-06-21 09:13:34,384 DEBUG [Thread-8]: => 
> MessageServiceHandler.getNextUndeliveredMessage
> 2005-06-21 09:13:34,384 DEBUG [Thread-8]: => 
> MessageServer.getUndeliveredMessages
> 2005-06-21 09:13:34,384 DEBUG [Thread-8]: => 
> DbConnectionPool.getConnection
> 2005-06-21 09:13:34,384 DEBUG [Thread-8]: => 
> 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]: => Transaction.rollback 
> (txID: #2323)
> 2005-06-21 09:13:35,352 DEBUG [Thread-8]: <= Transaction.rollback
> 2005-06-21 09:13:35,352 DEBUG [Thread-8]: => 
> MessageServiceHandler.getNextUndeliveredMessage
> 2005-06-21 09:13:35,352 DEBUG [Thread-8]: => 
> MessageServer.getUndeliveredMessages
> 2005-06-21 09:13:35,352 DEBUG [Thread-8]: => 
> DbConnectionPool.getConnection
> 2005-06-21 09:13:35,352 DEBUG [Thread-8]: => 
> 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]: => Transaction.rollback 
> (txID: #2338)
> 2005-06-21 09:13:42,384 DEBUG [Thread-8]: <= Transaction.rollback
> 2005-06-21 09:13:42,384 DEBUG [Thread-8]: => 
> MessageServiceHandler.getNextUndeliveredMessage
> 2005-06-21 09:13:42,384 DEBUG [Thread-8]: => 
> MessageServer.getUndeliveredMessages
> 2005-06-21 09:13:42,384 DEBUG [Thread-8]: => 
> DbConnectionPool.getConnection
> 2005-06-21 09:13:42,384 DEBUG [Thread-8]: => 
> 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 = 200
>  HTTP response message = OK
>     at 
> hk.hku.cecid.phoenix.message.handler.Request.expectMapResponse(Unknown 
> Source)
>     at 
> hk.hku.cecid.phoenix.message.handler.Request.sendMessageServiceHandlerConfig(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.java: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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