Hi,
At the very beginning - sorry for the size of this message but I wanted to
present all things I did to solve the problem I met.
>From some time I've been trying to solve the problem with DB connection and
more precisly with multiple concurent DB connections. So
far I've tried both JDBC pool and connection manager. Both are working OK
for some time (about an hour or two) and then most
connections taken from the pool are not valid. Before I describe the details
I must mention that everything works fine with
small number of DB connections - such tests of EJB application, I'm working
on, were running for more than 48 hours without
any problems. And here are the details concerning the problem:
****************************************************************************
**********************
- when I used JDBC pool with the following configuration:
***************************************
<mbean code="org.jboss.jdbc.XADataSourceLoader"
name="DefaultDomain:service=XADataSource,name=MSSQLDB">
<attribute
name="DataSourceClass">org.jboss.pool.jdbc.xa.wrapper.XADataSourceImpl</attr
ibute>
<attribute name="PoolName">MSSQLDB</attribute>
<attribute name="Properties">user=xxx;password=xxx</attribute>
<attribute
name="URL">jdbc:weblogic:mssqlserver4:[EMAIL PROTECTED]:1433</attribute>
<attribute name="GCMinIdleTime">1200000</attribute>
<attribute name="MaxSize">50</attribute>
<attribute name="GCEnabled">true</attribute>
<attribute name="InvalidateOnError">true</attribute>
<attribute name="TimestampUsed">true</attribute>
<attribute name="Blocking">true</attribute>
<attribute name="GCInterval">120000</attribute>
<attribute name="IdleTimeout">2800000</attribute>
<attribute name="IdleTimeoutEnabled">true</attribute>
<attribute name="LoggingEnabled">true</attribute>
<attribute name="MaxIdleTimeoutPercent">1.0</attribute>
<attribute name="MinSize">1</attribute>
</mbean>
the exceptions received look like this:
///////////////////////////////////////////////
[MSSQLDB] Pool MSSQLDB [10/10/50] gave out pooled object:
org.jboss.pool.jdbc.xa.wrapper.XAConnectionImpl@3a6ecc
[Default] user.dao: get connection
[Default] alert.dao: closing connection
[Default] Transaction exception: com.vitalcontact.vcp.data.DataException:
javax.ejb.FinderException: SQLException while
checking for an existing alert - name -> 6722655_31-alt :
weblogic.jdbcbase.mssqlserver4.TdsException: I/O exception while
talking to the server, java.net.SocketException: Connection reset by peer:
socket write error
[Default] user: store
[Transact] XAException: tx=XidImpl [FormatId=257, GlobalId=smart//212,
BranchQual=] errorCode=XA_UNKNOWN(0)
[MSSQLDB] Pool MSSQLDB [9/9/50] destroyed object
org.jboss.pool.jdbc.xa.wrapper.XAConnectionImpl@387202.
[Default] user.dao: closing connection
[Default] lang-context: get user model
[Default] user: activate
[Default] user: load
[Default] user.dao: queryString is: SELECT
usr_id,nms_id,usr_login,usr_password,usr_xml_def FROM VC_USERS WHERE usr_id
= '535'
[Default] user.dao: get connection
[Default] Fri Jun 29 03:03:39 EDT 2001: worker-6: transaction exception:
javax.transaction.TransactionRolledbackException:
null; nested exception is: javax.ejb.EJBException
javax.ejb.EJBException at
com.vitalcontact.vcp.transaction.ejb.TransactionEJB.executeTransaction(Trans
actionEJB.java:244)
at java.lang.reflect.Method.invoke(Native Method)
at
org.jboss.ejb.StatelessSessionContainer$ContainerInterceptor.invoke(Stateles
sSessionContainer.java:543)
at
org.jboss.ejb.plugins.StatelessSessionInstanceInterceptor.invoke(StatelessSe
ssionInstanceInterceptor.java:87)
at
org.jboss.ejb.plugins.TxInterceptorCMT.invokeNext(TxInterceptorCMT.java:133)
at
org.jboss.ejb.plugins.TxInterceptorCMT.runWithTransactions(TxInterceptorCMT.
java:298)
at org.jboss.ejb.plugins.TxInterceptorCMT.invoke(TxInterceptorCMT.java:99)
at
org.jboss.ejb.plugins.SecurityInterceptor.invoke(SecurityInterceptor.java:12
7)
at org.jboss.ejb.plugins.LogInterceptor.invoke(LogInterceptor.java:195)
at
org.jboss.ejb.StatelessSessionContainer.invoke(StatelessSessionContainer.jav
a:286)
at
org.jboss.ejb.plugins.jrmp.server.JRMPContainerInvoker.invoke(JRMPContainerI
nvoker.java:480)
at
org.jboss.ejb.plugins.jrmp.interfaces.GenericProxy.invokeContainer(GenericPr
oxy.java:335)
at
org.jboss.ejb.plugins.jrmp.interfaces.StatelessSessionProxy.invoke(Stateless
SessionProxy.java:123)
at $Proxy10.executeTransaction(Unknown Source)
at
com.vitalcontact.vcp.engine.ThreadPool$WorkerThread.processAlertEvent(Thread
Pool.java:183)
at
com.vitalcontact.vcp.engine.ThreadPool$WorkerThread.run(ThreadPool.java:134)
//////////////////////////////////////////////
or like this:
/////////////////////////////////////////////
[MSSQLDB] Pool MSSQLDB [5/10/50] gave out pooled object:
org.jboss.pool.jdbc.xa.wrapper.XAConnectionImpl@7140d0
[Default] user.dao: get connection
[Default] user.dao: closing connection
[Default] Transaction exception: com.vitalcontact.vcp.lang.ExecuteException:
lang context initialization failed:
javax.ejb.FinderException: SQLException while checking for an existing
user - name -> loadTest4 :
weblogic.jdbcbase.mssqlserver4.TdsException: I/O exception while talking to
the server, java.net.SocketException: Connection
reset by peer: JVM_recv in socket input stream read
[Transact] XAException: tx=XidImpl [FormatId=257, GlobalId=smart//256,
BranchQual=] errorCode=XA_UNKNOWN(0)
////////////////////////////////////////////// etc..
These exceptions are generated during SQL query execution on the connections
received from the pool
(dbConncetion.executeQuery(...)). I am aware that DB can close its
connections and the app server is not informed about that.
In such situation calling isClosed() on such connection (closed by the DB)
will return false because noone called close() on
this connection earlier. In order to avoid that I made a loop that tests the
connection (through the execution of simple SQL
query) and closes it (dbConnection.close()) in case of SQL exception
appearance:
////////////////////////////////////////////
...
while (true) {
try {
dbConnection = dataSource.getConnection();
Debug.printEvent("Get-Connection Loop: connection received",
"Connection Reference: " + dbConnection);
try {
Statement stmt = dbConnection.createStatement();
ResultSet result = stmt.executeQuery(queryStr);
stmt.close();
} catch (Exception e) {
if(!dbConnection.isClosed()) {
Debug.println("### BEFORE CLOSING THE CONNECTION ###");
dbConnection.close();
Debug.println("### AFTER CLOSING THE CONNECTION ###");
}
throw new Exception("Invalid connection !!!");
}
} catch(Exception e) {
Debug.printEvent("Get-Connection Loop ONLY: ", "connection
invalid - loop number: "+loopNo);
loopNo+=1;
file://e.printStackTrace();
continue;
}
Debug.printEvent("Get-Connection Loop ONLY: ", "connection valid -
loop number: "+loopNo);
break;
}
return dbConnection;
//////////////////////////////////////////
As you can see I assumed here that after one or few attempts new connection
received from the pool will be valid. However my
assumption was wrong because either after few or thousands of attempts,
valid connection to the DB was not established. It
looks like each time JDBC pool returns the reference to the same physical
connection (inside this loop there were no logs
saying that DB connetion is gave out from the pool or returned to the pool
or distroyed).
(I tried also different numbers of MaxSize attribute included in JDBC pool
configuration like 100, 1000, 10000 but with no
influence on results.)
****************************************************************************
**********************
- when I used connection manager with the following configuration (instead
of JDBC pool):
***************************************
///////////////////////////////////////////
<mbean code="org.jboss.resource.ConnectionFactoryLoader"
name="JCA:service=ConnectionFactoryLoader,name=MSSQLDB">
<attribute name="FactoryName">MSSQLDB</attribute>
<attribute name="RARDeployerName">JCA:service=RARDeployer</attribute>
<attribute name="ResourceAdapterName">
Minerva JDBC LocalTransaction ResourceAdapter
</attribute>
<attribute name="Properties">
ConnectionURL=jdbc:weblogic:mssqlserver4:[EMAIL PROTECTED]:1433;user=xxx;p
assword=xxx
</attribute>
<attribute name="ConnectionManagerFactoryName">
MinervaSharedLocalCMFactory
</attribute>
<attribute name="ConnectionManagerProperties">
# Pool type - uncomment to force, otherwise it is the default
#PoolConfiguration=per-factory
# Connection pooling properties - see
# org.jboss.pool.PoolParameters
MinSize=1
MaxSize=10000
Blocking=false
GCEnabled=true
IdleTimeoutEnabled=true
InvalidateOnError=true
TrackLastUsed=tue
GCIntervalMillis=120000
GCMinIdleMillis=1200000
IdleTimeoutMillis=2800000
MaxIdleTimeoutPercent=1.0
LoggingEnabled=true
TimestampUsed=true
</attribute>
<attribute name="PrincipalMappingClass">
org.jboss.resource.security.ManyToOnePrincipalMapping
</attribute>
<attribute name="PrincipalMappingProperties">
userName=xxx
password=xxx
</attribute>
</mbean>
/////////////////////////////////////////
received results were similar. After about 170 connections ([MSSQLDB] Pool
org.jboss.pool.connector.jdbc.JDBCManagedConnectionFactory-1
[170/170/Unlimited]) similar/the same exceptions, as presented above, are
generated.
I tried to overwrite default settings of unlimited number of connections
opened to the database but without success. I can't
find good way to define "ConnectionManagerProperties" (I tried few) to
overwrite default settings from
org.jboss.pool.PoolParameters.java . I tried also to download snapshots of
the sources (jbosspool-cvs.zip and jboss-cvs.zip)
in order to change the pool parameters directly in the code and then compile
and run JBOSS server. Unfortunatelly after any
change of pool parameters in org.jboss.pool.PoolParameters.java, JBOSS
server did not start correctly (some
java.nullPointerExceptions were generated) and the connection to the DB was
not established even once. When I returned to the
default settings of pool parameters, JBOSS started OK and the situation was
the same as described above.
In case of connection manager I've got also the problem to force JBOSS to
bind the pool in JNDI before the servlet starts to
work.
****************************************************************************
Now my questions are as follows:
Why can't I receive valid connection from JDBC pool by using the loop
presented above ?
How to overwrite default settings of the connection manager ?
How to force JBOSS first to create the pool and bind it in JNDI and then to
start the servlet ?
Is the aproach I took to solve this problem correct ?
Maybe someone had similar problem and found out sth helpful ?!
Please help me with this problem and of course thanks in advance.
Best regards,
Edyta Kalka
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