I am using spring / hibernate / mysql and currently using the following settings in spring-hibernate.xml
I am constantly seeing "select @@session.tx_read_only" and "select @@session.tx_isolation" queries being sent to the DB mostly after select statements for actual data.
Each of these queries add like 20-25ms time and I get like 70 queries run against the DB on a Oauth login. How can I get rid of them ?
I tried statelessSessions and the queries disappeared and I could reduce the number of queries to the application queries only but I read that using statelessSessions will not provide any first-level cache and its also vulnerable to data aliasing effects.
How can I avoid the "select @@session.tx_read_only" and select @@session.tx_isolation" running multiple times.(I use a generic Dao to access the DB a extract is given below) i am using findById, findAll, getNamedQueryAndNamedParam methods...
spring-hibernate.xml
<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource" destroy-method="close">
<property name="driverClass" value="com.mysql.jdbc.Driver" />
<property name="jdbcUrl" value="${JDBC_CON_STRING}" />
<property name="user" value="${USER_NAME}" />
<property name="password" value="${USER_PASSWORD}" />
</bean>
<bean id="sessionFactory" class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">
<property name="dataSource" ref="dataSource" />
<property name="packagesToScan" value="com.model" />
<property name="hibernateProperties">
<props>
<prop key="hibernate.dialect">org.hibernate.dialect.MySQLInnoDBDialect</prop>
<prop key="hibernate.show_sql">true</prop>
<prop key="hibernate.format_sql">true</prop>
<prop key="hibernate.hbm2ddl.auto">false</prop>
<prop key="hibernate.cache.region.factory_class">org.hibernate.cache.ehcache.EhCacheRegionFactory</prop>
<prop key="hibernate.cache.use_query_cache">true</prop>
<prop key="hibernate.cache.use_second_level_cache">true</prop>
<prop key="hibernate.cache.provider_configuration_file_resource_path">ehcach.xml</prop>
<prop key="hibernate.auto_close_session">true</prop>
</property>
<property name="mappingResources">
<list>
<value>named-queries.xml</value>
<value>native-named-queries.xml</value>
</list>
</property>
</bean>
<bean id="transactionManager" class="org.springframework.orm.hibernate4.HibernateTransactionManager">
<property name="sessionFactory" ref="sessionFactory" />
<property name="dataSource" ref="dataSource" />
</bean>
<tx:annotation-driven transaction-manager="transactionManager" />
<bean id="testClassDao" class="com.dao.GenericHibernateDao">
<property name="clazz" value="com.model.TestClass" />
</bean>
GenericHibernateDao.java
@Repository
@Scope("prototype")
public class GenericHibernateDao<T, PK extends Serializable> implements GenericDao<T, PK> {
private Class<T> clazz;
@Autowired
private SessionFactory sessionFactory;
public void setClazz(final Class<T> clazzToSet) {
this.clazz = clazzToSet;
}
protected Session getSession() {
return sessionFactory.getCurrentSession();
}
protected Session getOpenSession() {
return sessionFactory.openSession();
}
@Transactional(isolation = Isolation.READ_COMMITTED, propagation = Propagation.REQUIRED)
public T findById(PK id) {
Object obj = null;
obj = getSession().get(clazz, id);
//obj = getStatelessSession().get(clazz, id);
return (T) obj;
}
@Transactional(isolation = Isolation.READ_COMMITTED, propagation = Propagation.REQUIRED)
public List<T> findAll() {
String queryString = "from " + clazz.getName();
Query query = getSession().createQuery(queryString);
query.setCacheable(true);
List<T> list = query.list();
return list;
}
@Transactional(isolation = Isolation.READ_COMMITTED, propagation = Propagation.REQUIRED)
public List<T> getNamedQuery(String queryName) {
Query query = getSession().getNamedQuery(queryName);
//Query query = getStatelessSession().getNamedQuery(queryName);
query.setCacheable(true);
List<T> results = query.list();
return results;
}
@Transactional(isolation = Isolation.READ_COMMITTED, propagation = Propagation.REQUIRED)
public List<T> getNamedQueryAndNamedParam(String queryName, String paramName, Object value) {
Query query = getSession().getNamedQuery(queryName).setString(paramName, value.toString());
query.setCacheable(true);
List<T> results = query.list();
return results;
}
@Transactional(isolation = Isolation.READ_COMMITTED, propagation = Propagation.REQUIRED)
public PK save(T persistenceObject) {
Serializable save = getSession().save(persistenceObject);
return (PK) save;
}
@Transactional(isolation = Isolation.READ_COMMITTED, propagation = Propagation.REQUIRED)
public void saveOrUpdate(T persistenceObject) {
getSession().saveOrUpdate(persistenceObject);
}
public void saveOrUpdateBulk(Collection<T> persistenceObject) {
Session session = getOpenSession();
Transaction tx = session.beginTransaction();
int i = 0;
for (Iterator<T> iterator = persistenceObject.iterator(); iterator.hasNext();) {
i++;
session.saveOrUpdate(iterator.next());
if (i % 100 == 0) {
session.flush();
session.clear();
}
}
tx.commit();
session.close();
}
@Transactional(isolation = Isolation.READ_COMMITTED, propagation = Propagation.REQUIRED)
public boolean delete(PK id) {
Object findById = findById(id);
if (findById != null) {
getSession().delete(findById);
return true;
}
return false;
}
}