JTDS and JBOSS JDBC Connection Pool Problem, any solution? Maybe a custom ValidConnectionChecker? - jdbc

Question

I'm facing a weird production problem. Environment is the following:
JBOSS 4.0.2
SQL Server 2005
Driver JTDS 1.2.5
From time to time the following szenario occurs.
A SQL command fails to Excute with
java.sql.SQLException: I/O Error: Read timed out
(I can live with that, if it just happens twice a day or so)
But from that moment on the connection seems to be wasted without the pool recognizing it, as I continously receive
java.sql.SQLException: Invalid state, the Connection object is closed.
from that moment on. The only thing that helps is restarting JBOSS. This occurs despite of the fact that I have
<check-valid-connection-sql>select getdate()</check-valid-connection-sql>
set up in my Datasource definition.
I was wondering if I can use a custom ValidConnectionChecker, that either rebuilds the connection itself, or explicitly throws a Exception to fix this. Maybe anyone has other suggestions.
Here is my complete DS definition.
<local-tx-datasource>
<jndi-name>MyDS</jndi-name>
<connection-url>jdbc:jtds:sqlserver://192.168.35.235:1433/MyDb;user=user1;password=pwd;appName=MyApp;loginTimeout=15;socketTimeout=120</connection-url>
<driver-class>net.sourceforge.jtds.jdbc.Driver</driver-class>
<user-name>user1</user-name>
<password>pwd</password>
<min-pool-size>10</min-pool-size>
<max-pool-size>25</max-pool-size>
<blocking-timeout-millis>60000</blocking-timeout-millis>
<idle-timeout-minutes>1</idle-timeout-minutes>
<check-valid-connection-sql>select getdate()</check-valid-connection-sql>
</local-tx-datasource>
Any help appriciated.
Regards

Answer 1

Try changing your driver class line to
net.sourceforge.jtds.jdbcx.JtdsDataSource.
net.sourceforge.jtds.jdbc.Driver doesn't implement the javax.sql.ConnectionPoolDataSource interface.
source:
http://jtds.sourceforge.net/faq.html#features

Answer 2

Probably too late the solution, but I am stuck with the jtds driver here. Hope this saves half an hour of your productive time.
The fix is to specify a validationQuery to the Apache dbcp2 Connection Pool implementation.
For jtds/sql server
I specified the spring configuration as follows:
<bean id="sqlServerDS" class="org.apache.commons.dbcp2.BasicDataSource" destroy-method="close" >
<property name="driverClassName" value="${jdbc.driverClassName}" />
<property name="url" value="${jdbc.url}" />
<property name="username" value="${jdbc.username}" />
<property name="password" value="${jdbc.password}" />
<property name="defaultReadOnly" value="true" />
<property name="validationQuery" value="select 1" />
</bean>
In case you are not using Spring, call setValidationQuery method on BasicDataSource in your java code.
BasicDataSource bds = new BasicDataSource();
bds.setValidationQuery("select 1");

Answer 3

Connection.isValid() isn't implemented in JTDS.
I found even catching the exception and forcing a complete restart of the connection didn't work.