Re: Problem with Geronimo 1.0, PreparedStatements, pools and MaxDB

Wed, 31 May 2006 16:23:18 -0700 

Going up the call stack I noticed that the commit on the
connection is only done when commitBeforeAutoCommit is true.
My commitBeforeAutoCommit is false as suggested. Why is
the Autocommit set always to true?

protected void localTransactionCommit(boolean isSPI) throws ResourceException {
        Connection c = (Connection) physicalConnection;
        try {
            if (commitBeforeAutoCommit) {
                c.commit();
            }
            c.setAutoCommit(true);
        } catch (SQLException e) {
            try {
                c.rollback();
            } catch (SQLException e1) {
                if (log != null) {
                    e.printStackTrace(log);
                }
            }
            throw new LocalTransactionException("Unable to commit", e);
        }
        super.localTransactionCommit(isSPI);
}

In the case of MaxDB you can configure the db to not use
Autocommit. Every setting of Autocommit via the JDBC driver
is ignored then. Set Autocommit without a following update
or close on the connection does nothing in case of the MaxDB
driver and already disabled Autocommit.

here is the drivers code:

    /**
     * setAutoCommit method comment.
     */
    public void setAutoCommit(boolean autoCommit)
        throws java.sql.SQLException
    {
        this.assertOpen ();
        if (autoCommit){
            this.commit();
        }
        this.autocommit = autoCommit;
    }

I really don't understand that commitBeforeAutoCommit thingy
it must be a workaround for some driver, but for all connections
without c.getAutoCommit() == true only the commit should happen.

        try {
            if (c.getAutoCommit() && commitBeforeAutoCommit) {
                c.commit();
                c.setAutoCommit(true);
            } else {
                c.commit();
            }
        } catch (SQLException e) {

Looks a bit tautologous but does the same for the commitBeforeAutoCommit
users as before and the simple commit for all without Autocommit.

Thanks,
Mario



Mario Rübsam wrote:

Ok, I couldn't resist and started debugging

it leads me to some code which enables Autocommit on the connection
just before calling some listeners for localTransactionCommit
this setting of Autocommit is also logged by the MaxDB JDBC logger
and the last code in Tranql
protected void localTransactionCommit(boolean isSPI) throws ResourceException { 
        if (!isSPI) {
ConnectionEvent event = new ConnectionEvent(this, ConnectionEvent.LOCAL_TRANSACTION_COMMITTED); 
            for (int i = listeners.size() - 1; i >= 0; i--) {
ConnectionEventListener listener = (ConnectionEventListener) listeners.get(i); 
                listener.localTransactionCommitted(event);
            }
        }
    }

there is only one listerner to call the GeronimoConnectionEventListener
and the method localTransactionCommitted and right here is my problem

    /**
     * The <code>localTransactionCommitted</code> method
     *
     * @param event a <code>ConnectionEvent</code> value
     * todo implement this method
     */
    public void localTransactionCommitted(ConnectionEvent event) {
    }

Geronimo source was from the trunk, Is this the 1.0 code?
What should I do now?

Thanks,
Mario



David Jencks wrote:


On May 31, 2006, at 2:39 PM, Mario Rübsam wrote:


David,

where can I get the source for Traql 1.2.1? I will try to debug
that commit handling.


svn co https://svn.codehaus.org/tranql/trunk/connector
will get the current source code: if it's not exactly the same was what has been released it should be pretty close. 



I have AutoCommit always off because I need the transaction
control so CommitBeforeAutocommit=true was no help for my problem.


I was pretty sure that was the case :-)

thanks
david jencks



Thanks,
Mario



David Jencks wrote:

Mario,
I don't see an obvious way for this stuff to break, but if you are set up for debugging you could get the tranql connector source code and trace through starting at org.tranql.connector.jdbc.ConnectionHandle.commit(). I don't see how the commit call wouldn't get eventually to the db, but knowing which path execution takes should make it simpler to figure out what is going on. BTW someone was mentioning setting CommitBeforeAutocommit to true. You should only set this on very buggy jdbc drivers that violate the jdbc spec by not committing pending work when you set autocommit to true (axion). Any real database should not need this set. 
thanks
david jencks
On May 31, 2006, at 11:05 AM, Mario Rübsam wrote:

Santosh,
I did the development mostly on PostgreSQL. It's working there but don't know 
if the commits come through or if the DB handle it in some way.
I can't test Derby atm because I have to setup a separate Derby server to import 
all the data needed. That needs to much time.

Thanks,
Mario


Santosh Koti wrote:

Mario,
Can u try the same thing on the Derby ,if it is not cumbersome  :)
I think tranQL has better support for Derby.
PS: Ofcourse it may not solve ur MaxDB problem ,but atleast it says ur code is safe enough :) 
Thanks,
Santosh.
"Don't talk about yourself; it will be done when you leave. "
 -----Original Message-----
From: Santosh Koti [mailto:[EMAIL PROTECTED] Sent: Wednesday, May 31, 2006 11:10 PM 
To: [email protected]
Subject: RE: Problem with Geronimo 1.0, PreparedStatements, pools and MaxDB 
Mario,
I agree that is not a solution , but atleast it points out that the problem is cornered around TranQL ?? . (That's what I suspect !! If so, then look smething on transQL config, or may need to chk for next release :) Time for the gurus to dive in here !! :) 
Thanks,
Santosh.
"Don't talk about yourself; it will be done when you leave. "
 -----Original Message-----
From: Mario Rübsam [mailto:[EMAIL PROTECTED] Sent: Wednesday, May 31, 2006 10:55 PM 
To: [email protected]
Subject: Re: Problem with Geronimo 1.0, PreparedStatements, pools and MaxDB 
Santosh,
Santosh Koti wrote:

Mario,

Just give another try (of course a wild advise :-))

I did ;)
After running the transactions , chk ur DB for any updates, then bring the server down -> & then chk ur DB, whether commit is happening the moment u trigger the server with a shutdown event ?? 
data is committed with shutdown, but that is not a solution

If so , some configuration needs to be looked at ? !

here is what I did now:
instead of calling:
mConnection.commit()
I did the following:
Statement tStatement = mConnection.createStatement();
tStatement.executeUpdate("COMMIT");
this is dirty but working, all commits are registered on the MaxDB server this is bypassing all the commit stuff in the Tranql Connection object 
and the driver
So I find me now debugging the commit stuff in the Connection instance. 
Thanks,
Mario



Thanks,
Santosh.
"Don't talk about yourself; it will be done when you leave. "

-----Original Message-----
From: Mario Rübsam [mailto:[EMAIL PROTECTED] Sent: Wednesday, May 31, 2006 9:54 PM 
To: [email protected]
Subject: Re: Problem with Geronimo 1.0, PreparedStatements, pools and MaxDB 

Santosh,

it works, but only in the following situation:

open connection --> call update --> commit


if you I do a:

open connection --> call query --> call update --> commit

no commit happen on server, like without commitbeforeautocommit=true
Strange is that CommitBeforeAutocommit is a workaround for setAutoCommit(true) 
which I don't use. And "setAutoCommit(true)" also doesn't commit.

Thanks,
Mario


Santosh Koti wrote:

Mario,

 Can u give a try for :
commitbeforeautocommit="true" in ur db deployment plan.
Not sure, but may work, I had the same problem with delayed EJB's commit. 


Thanks,
Santosh.
"Don't talk about yourself; it will be done when you leave. "



-----Original Message-----
From: Mario Rübsam [mailto:[EMAIL PROTECTED]

Sent: Wednesday, May 31, 2006 7:11 PM
To: [email protected]
Subject: Re: Problem with Geronimo 1.0, PreparedStatements, pools and MaxDB 

The "setAutoCommit(false)" is required by MaxDB because
it's default is "on".

I debugged the connections open and close and I can see
the connections (db sessions on the MaxDB server) come
and go when I do this. The only thing that not happen
on the server is the Connection.commit() whe I call it.

If I use the direct driver connection I can see the
commit in the stats immediately after I call the commit.
If I use the connection from the pool no commit happens
on the server.

Is there any delayed commit mechanism implemented?

Thanks,
Mario



Aaron Mulder wrote:

The one thing that looked suspicious in your code was the
setAutoCommit -- that shouldn't be done in a J2EE environment. Can 
you try commenting out that line and see if it makes a difference?
If that doesn't help, can you put printlns near where you close the connections and just convince yourself that they're definitely being 
closed?

Thanks,
    Aaron

On 5/31/06, Mario Rübsam <[EMAIL PROTECTED]> wrote:

Hi,

I testet a bit further and tried the following situations:
I used a direct driver connection without the Geronimo pool --> working 

I disabled all write access to the tables were the hang occurs,
only read access enabled --> working

I checked (with the MaxDB Database Manager) the connections/db
sessions all
open and close correct so thats not the problem.

So my conclusion is that there is something different with the
transactions and Tranql. I debugged the commits and if I use the
direct driver connection I can see the commits in the Database Manager 
stats. If I commit on the Tranql connection the commit is not
registered on the MaxDB server.

Is this now a driver or a Tranql issue?

Thanks,
Mario



Mario Rübsam wrote:

Aaron,
here is a stack trace attached, it hangs sometimes when calling the prepareStatement and sometimes when executing the statement and it's 
not always the same statement.

Thanks,
Mario



Mario Rübsam wrote:

Aaron,
connections are correctly closed. If they are returned to the pool, 
don't know?
The code that opens/closes connections is a bit widespread and wrapped into a db abstraction layer. Here are some code fragments collected 
together without the try catches.


open connection:

InitialContext tCtx = new InitialContext();

mJDBCDataSource = (DataSource)tCtx.lookup(
  pDataSource.getString(PDbDataSource.URL));

String tUser = pDataSource.getString(PDbDataSource.USER, null);
String tPass = pDataSource.getString(PDbDataSource.PASS, null);

if (tUser != null) {
    mConnection = mJDBCDataSource.getConnection(tUser, tPass);
} else {
    mConnection = mJDBCDataSource.getConnection();
}

mConnection.setAutoCommit(false);



call statements:

String tStmtSQL = "SELECT ....";
PreparedStatement tStmt = mConnection.prepareStatement(tStmtSQL); 

tStmt.setString(1, tName);
ResultSet tRS = tStmt.executeQuery();

while (tRS.next()) {
...
}

tRS.close();
tStmt.close();



close the connection:

mConnection.close();



The DataSource lookup happens only once. After that I only
call getConnection() on the DS and close() on the connection.

Thanks,
Mario



Aaron Mulder wrote:
It sounds like connections are not being returned to the pool, though it's hard to know without a stack trace. Also, can you post the code you're using to access the connection pool, execute the prepared statements, and close the connection? And what kind of component is 
running these prepared statements?

Thanks,
   Aaron

On 5/30/06, Mario Rübsam <[EMAIL PROTECTED]> wrote:

Hi,
I have some serious problems when executing prepared statements on MaxDB with pooled connections managed by Tranql in Geronimo 1.0. 

The problem is, that after calling a lot of these prepared

statements

the connection will hang until I get a timout. It's always
a different statement that worked just fine some milliseconds

before.

There is no CPU load on the Geronimo machine and also no load
on the DB machine. Just a hang up until timeout.
I can run the same app on MySQL 4.x or PostgrSQL 8.x without any Problems. Also no problems with a client app and MaxDB that do a batch import and use exactly the same statements but without db 
pooling.

So I think it must be a db pool problem with the MaxDB or a
strange behaviour with that driver and connection pools.

Any suggestions where I can start analysing the problem?

here my MaxDB plan:

<?xml version="1.0" encoding="UTF-8"?>
<connector configId="user/database-pool-jdbc/default/1/car"
xmlns="http://geronimo.apache.org/xml/ns/j2ee/connector-1.0";>
     <dep:dependency
xmlns:dep="http://geronimo.apache.org/xml/ns/deployment-1.0";>
         <dep:uri>mysql/sapdbc/7.6/jar</dep:uri>
     </dep:dependency>
     <resourceadapter>
         <outbound-resourceadapter>
             <connection-definition>
<connectionfactory-interface>javax.sql.DataSource</connectionfactory-interface> 
                 <connectiondefinition-instance>
                     <name>jdbc/default</name>
                     <config-property-setting
name="UserName">sse</config-property-setting>
                     <config-property-setting
name="Password">sse</config-property-setting>
                     <config-property-setting
name="CommitBeforeAutocommit">false</config-property-setting>
                     <config-property-setting
name="Driver">com.sap.dbtech.jdbc.DriverSapDB</config-property-setting> 
                     <config-property-setting
name="ExceptionSorterClass">org.tranql.connector.AllExceptionsAreFatalSorter</config-property-setting> 
                     <config-property-setting
name="ConnectionURL">jdbc:sapdb://192.168.8.3/service</config-property-setting> 
                     <connectionmanager>
                         <local-transaction/>
                         <single-pool>
                             <max-size>100</max-size>
                             <min-size>50</min-size>
<blocking-timeout-milliseconds>60000</blocking-timeout-milliseconds> 

<idle-timeout-minutes>60</idle-timeout-minutes>
                             <match-one/>
                         </single-pool>
                     </connectionmanager>
                 </connectiondefinition-instance>
             </connection-definition>
         </outbound-resourceadapter>
     </resourceadapter>
</connector>


Thanks,
Mario
------------------------------------------------------------------------ 
DEBUG  DATE=2006-05-30 TIME=13:42:22:046 CATEGORY=cpa.db
[EMAIL PROTECTED]:CDbContext.getPreparedStatement() SID=cpa.1-1-1.cpa 
MESSAGE=prepare statement "SELECT
TbRegistryValues.TcValueText,TbRegistryValues.TcValueLineNo FROM
TbRegistry,TbRegistryValues WHERE
((TbRegistry.TcEntityId=TbRegistryValues.TcEntityId) AND
(TbRegistry.TcDomain=?)) ORDER BY TbRegistryValues.TcValueLineNo"

DEBUG  DATE=2006-05-30 TIME=17:38:50:421 CATEGORY=cpa.db
[EMAIL PROTECTED]:CDbContext.getPreparedStatement() SID=cpa.1-1-1.cpa 
MESSAGE=prepared statement
"[EMAIL PROTECTED]"

13:42:22,046 WARN  [GeronimoConnectionEventListener]

connectionErrorOccurred called with null
com.sap.dbtech.jdbc.exceptions.ConnectionException: [-708] Timeout 
      at
com.sap.dbtech.jdbc.ConnectionSapDB.execute(ConnectionSapDB.java:554) 
      at
com.sap.dbtech.jdbc.CallableStatementSapDB.sendCommand(CallableStatementSapDB.java:1764) 
      at
com.sap.dbtech.jdbc.StatementSapDB.sendSQL(StatementSapDB.java:808) 
      at
com.sap.dbtech.jdbc.CallableStatementSapDB.doParse(CallableStatementSapDB.java:233) 
      at
com.sap.dbtech.jdbc.CallableStatementSapDB.constructor(CallableStatementSapDB.java:186) 
      at
com.sap.dbtech.jdbc.CallableStatementSapDB.<init>(CallableStatementSapDB.java:88) 
      at
com.sap.dbtech.jdbc.ConnectionSapDB.prepareStatement(ConnectionSapDB.java:803) 
      at
org.tranql.connector.jdbc.ConnectionHandle.prepareStatement(ConnectionHandle.java:231) 
      at
com.coderesearch.cpa.db.jdbc.CDbContext.getPreparedStatement(CDbContext.java:1131) 
      at
com.coderesearch.cpa.reg.db.jdbc.CDbBrokerRegistry.lookup(CDbBrokerRegistry.java:129) 
      at
com.coderesearch.cpa.reg.db.jdbc.CDbBrokerRegistry.query(CDbBrokerRegistry.java:430) 
      at
com.coderesearch.cpa.naming.CPANamingContextDb.lookup(CPANamingContextDb.java:116) 
      at
com.coderesearch.cpa.reg.CPARegistryContext.lookup(CPARegistryContext.java:256)
at com.coderesearch.cpa.reg.Registry.lookupInt(Registry.java:199) 
      at
com.coderesearch.abp.index.srv.CRPIndex.countLogin(CRPIndex.java:140) 
      at
com.coderesearch.abp.index.srv.CRPIndex.process(CRPIndex.java:266) 
      at
com.coderesearch.abp.found.srv.MainServlet.process(MainServlet.java:482) 
      at
com.coderesearch.abp.found.srv.MainServlet.doPost(MainServlet.java:610)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:615) at javax.servlet.http.HttpServlet.service(HttpServlet.java:688) 
      at
org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:428) 
      at
org.apache.geronimo.jetty.JettyServletHolder.handle(JettyServletHolder.java:99) 
      at
org.mortbay.jetty.servlet.WebApplicationHandler$CachedChain.doFilter(WebApplicationHandler.java:830) 
      at
org.mortbay.jetty.servlet.JSR154Filter.doFilter(JSR154Filter.java:170) 
      at
org.mortbay.jetty.servlet.WebApplicationHandler$CachedChain.doFilter(WebApplicationHandler.java:821) 
      at
org.mortbay.jetty.servlet.WebApplicationHandler.dispatch(WebApplicationHandler.java:471) 
      at
org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:568)
at org.mortbay.http.HttpContext.handle(HttpContext.java:1530) 
      at
org.mortbay.jetty.servlet.WebApplicationContext.handle(WebApplicationContext.java:633)
at org.mortbay.http.HttpContext.handle(HttpContext.java:1482) at org.mortbay.http.HttpServer.service(HttpServer.java:909) 
      at

org.mortbay.http.HttpConnection.service(HttpConnection.java:816)

      at
org.mortbay.http.HttpConnection.handleNext(HttpConnection.java:982) 
      at

org.mortbay.http.HttpConnection.handle(HttpConnection.java:833)

      at
org.mortbay.http.SocketListener.handleConnection(SocketListener.java:244) 
      at

org.mortbay.util.ThreadedServer.handle(ThreadedServer.java:357)

      at

org.mortbay.util.ThreadPool$PoolThread.run(ThreadPool.java:534)
--


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