我经常使用内存中的HSQL数据库作为测试数据库来编写数据库相关代码的单元测试。最近，我决定从1.8.1.3升级到2.2.9，以利用在2.x版本分支中添加的ROW_NUMBER（）支持。

似乎在某种程度上，新版本比旧版本更严格。使用Hibernate（3.6.10）作为ORM，例如，我可能创建一个Configuration对象来创建first
SessionFactory，然后使用该对象来填充测试数据，然后将Configurationto
对象用于被测试的类，这将创建它自己SessionFactory进行选择。使用hsqldb
1.8.1.3，没问题。对于2.2.9，select块位于hsqldb代码内部。以下是SSCCE对此进行说明：

public void testTwoSessionFactories() throws Exception {
    boolean withTx = false;

    AnnotationConfiguration config = new AnnotationConfiguration().addAnnotatedClass(Entity.class);
    config.setProperty("hibernate.hbm2ddl.auto", "create");
    config.setProperty(Environment.DIALECT, HSQLDialect.class.getName());
    config.setProperty(Environment.DRIVER, jdbcDriver.class.getName());
    config.setProperty(Environment.URL, "jdbc:hsqldb:mem:testDB");
    config.setProperty(Environment.USER, "SA");
    config.setProperty(Environment.PASS, "");

    SessionFactory sessionFactory1 = config.buildSessionFactory();
    Session session = sessionFactory1.openSession();

    Transaction tx = null;
    if (withTx)
        tx = session.beginTransaction();

    session.save(new Entity("one"));

    if (withTx)
        tx.commit();

    session.flush();
    session.close();

    config.setProperty("hibernate.hbm2ddl.auto", "");
    SessionFactory sessionFactory2 = config.buildSessionFactory();
    Session session2 = sessionFactory2.openSession();
    List entities = session2.createCriteria(Entity.class).list();
    session2.close();
}

注意withTx布尔值。使用HSQLDB 1.8.1.3，我可以使用withTxtrue或false 运行此代码，这会很好。对于HSQLDB
2.2.9，withTx 必须将其设置为true ，否则线程将在.list()调用时被阻塞，并具有以下堆栈：

Unsafe.park(boolean, long) line: not available [native method]  
LockSupport.park(Object) line: not available    
CountDownLatch$Sync(AbstractQueuedSynchronizer).parkAndCheckInterrupt() line: not available 
CountDownLatch$Sync(AbstractQueuedSynchronizer).doAcquireSharedInterruptibly(int) line: not available   
CountDownLatch$Sync(AbstractQueuedSynchronizer).acquireSharedInterruptibly(int) line: not available 
CountDownLatch.await() line: not available  
CountUpDownLatch.await() line: not available    
Session.executeCompiledStatement(Statement, Object[]) line: not available   
Session.execute(Result) line: not available 
JDBCPreparedStatement.fetchResult() line: not available 
JDBCPreparedStatement.executeQuery() line: not available    
BatchingBatcher(AbstractBatcher).getResultSet(PreparedStatement) line: 208  
CriteriaLoader(Loader).getResultSet(PreparedStatement, boolean, boolean, RowSelection, SessionImplementor) line: 1953   
CriteriaLoader(Loader).doQuery(SessionImplementor, QueryParameters, boolean) line: 802  
CriteriaLoader(Loader).doQueryAndInitializeNonLazyCollections(SessionImplementor, QueryParameters, boolean) line: 274   
CriteriaLoader(Loader).doList(SessionImplementor, QueryParameters) line: 2542   
CriteriaLoader(Loader).listIgnoreQueryCache(SessionImplementor, QueryParameters) line: 2276 
CriteriaLoader(Loader).list(SessionImplementor, QueryParameters, Set, Type[]) line: 2271    
CriteriaLoader.list(SessionImplementor) line: 119   
SessionImpl.list(CriteriaImpl) line: 1716   
CriteriaImpl.list() line: 347   
EntityTest.testTwoSessionFactories() line: 46

HSQLDB在1.8.1.3和2.2.9之间进行了哪些更改，需要此代码在事务中进行保存，我可以将其关闭吗？