Atomikos Forum

Hello everyone,

I have been evaluating Atomikos for a couple of weeks and think I have encountered a bug, but since I exercise a very simple scenario, it very well may be due to misconfiguration or some limitation of Atomikos that I'm not aware of. Can anyone clarify?

The scenario is as follows:
Within global transaction I create two connections to DB.
I use them so that both are registered in transaction.
I close the first one and then take next one (usually the last closed is returned by the pool).
On any operation that would register this connection in existing transaction I can see that Atomikos is providing different XID than the first time, which leads to an Error from connection.

I tested it on 2 databases: H2 and MySQL with the same results. From looking in the code I can see that when second connection is opened it overwrites XID in SiblingMapper of global transaction. This new, I assume incorrect XID, is then used to operate on the first connection after it is closed and borrowed from pool again.

I attach a simple test case (in method testCase). It requires H2 to compile, but it can be easily replaced with MySQL driver.





package atomikos;

import java.sql.Connection;
import java.sql.SQLException;

import javax.sql.DataSource;
import javax.sql.XADataSource;
import javax.transaction.SystemException;

import org.h2.jdbcx.JdbcDataSource;

import pl.migi.hibernate.tutorial.Table;

import com.atomikos.icatch.jta.UserTransactionManager;
import com.atomikos.jdbc.AtomikosDataSourceBean;

public class TestCase {

    private XADataSource dataSource;
    private UserTransactionManager transactionManager;
    private AtomikosDataSourceBean dataSourceBean;
    private Connection connection;
    private Table table;

    public void createTransactionManager() throws SystemException {
        transactionManager = new UserTransactionManager();
        transactionManager.setTransactionTimeout(90000000);
        transactionManager.init();
        transactionManager.setTransactionTimeout(90000000);
    }

    public void createDataSource() throws SQLException {
        createH2DataSource();
        connection = ((DataSource) dataSource).getConnection();
        connection.setAutoCommit(true);
        dataSourceBean = new AtomikosDataSourceBean();
        dataSourceBean.setXaDataSource(dataSource);
        dataSourceBean.setPoolSize(2);
        dataSourceBean.setTestQuery("select * from information_schema.tables");
        dataSourceBean.setUniqueResourceName("xyz");
    }

    private void createH2DataSource() {
        JdbcDataSource jdbcDataSource = new JdbcDataSource();
        jdbcDataSource.setURL("jdbc:h2:mem:test;LOCK_MODE=1;MVCC=TRUE;DB_CLOSE_DELAY=-1");
        jdbcDataSource.setUser("sa");
        dataSource = jdbcDataSource;
    }

    // private void createMySQLBaseDataSource() {
    // MysqlXADataSource source = new MysqlXADataSource();
    // source.setURL("jdbc:mysql://localhost:3306/BPE?characterEncoding=UTF-8");
    // source.setUser("syncron");
    // source.setPassword("syncron");
    // dataSource = source;
    // }

    private void setUp() throws Exception {
        createTransactionManager();
        createDataSource();
    }

    public void testCase() throws Exception {
        setUp();

        transactionManager.begin();
        Connection connection1 = dataSourceBean.getConnection();
        Connection connection2 = dataSourceBean.getConnection();
        connection1.createStatement();
        connection2.createStatement();
        connection1.close();
        connection1 = dataSourceBean.getConnection();
        connection1.createStatement(); // this fails
        connection2.close();
    }

    public static void main(String[] args) throws Exception {
        new TestCase().testCase();
    }

}

What jta.properties are you using?

These are jta.properties contents:

com.atomikos.icatch.service=com.atomikos.icatch.standalone.UserTransactionServiceFactory
com.atomikos.icatch.enable_logging=false
com.atomikos.icatch.console_log_level=DEBUG

Hi,

Thanks. Although Atomikos is not doing st 'wrong' wrt XA, H2 does not seem able to handle it (few DBMS can handle this case BTW).

I will check if we can optimize anything.

Cheers

Hi,
thanks a lot. You are right, it does work on Oracle for instance. MySQL and H2 do not join transactions correctly when given different branch ID. We will keep that in mind.

Best regards,
Michał