Spring & Hibernate SessionFactory performance issue - spring

Question

I am facing a performance issue with Hibernate sessionFactory.
It is a Spring Boot - Hibernate app with a SessionFactory configured like this
#Bean
public SessionFactory sessionFactory(HibernateEntityManagerFactory hemf){
return hemf.getSessionFactory();
}
I have also tried all the different ways described in this question Spring Boot - Handle to Hibernate SessionFactory
My DAO looks like this
#Autowired
private SessionFactory sessionFactory;
#Transactional
public List<Type> findAll() {
return sessionFactory.getCurrentSession().createQuery("from Type").list();
}
When the number of concurrent db requests is bigger than the configured maximumPoolSize(10 in this example) then the application becomes unresponsive.
#RequestMapping(value = "/stress-sessionfactory")
public void stressTest(#RequestParam int threadsCount) {
List<Thread> threads = new ArrayList<>();
for (int i = 0; i < threadsCount; i++) {
final int k = i;
Runnable runnable
= () -> {
List<Type> all = typeDAOHibernate.findAll();
LOG.info("{}:sessionfactory:{} ", k, all.size());
};
Thread t = new Thread(runnable);
threads.add(t);
}
threads.stream().forEach(t -> t.start());
}
You can find a standalone example in github.
The example is configured with maximumPoolSize=10.
So if you just hit
http://localhost:8080/stress-sessionfactory?threadsCount=11 you will get the error I am talking about.
On the other hand a Spring Data repository can easily handle thousands of concurrent requests! (e.g http://localhost:8080/stress-jpa?threadsCount=2000)
I Have tried the same scenario with different datasources(Hikari, Tomcat) , different databases(oracle,h2) and different hibernate
versions( 5.011-Final,v4.3.11-Final) and I always get the same error.
Stacktrace
Exception in thread "Thread-51" Exception in thread "Thread-47" org.springframework.transaction.CannotCreateTransactionException: Could not open JPA EntityManager for transaction; nested exception is javax.persistence.PersistenceException: org.hibernate.exception.JDBCConnectionException: Unable to acquire JDBC Connection
at org.springframework.orm.jpa.JpaTransactionManager.doBegin(JpaTransactionManager.java:431)
at org.springframework.transaction.support.AbstractPlatformTransactionManager.getTransaction(AbstractPlatformTransactionManager.java:373)
at org.springframework.transaction.interceptor.TransactionAspectSupport.createTransactionIfNecessary(TransactionAspectSupport.java:447)
at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:277)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:656)
at com.example.dao.TypeDAOHibernate$$EnhancerBySpringCGLIB$$e6373e2e.findAll(<generated>)
at com.example.controller.StressController.lambda$stressTest$0(StressController.java:36)
at java.lang.Thread.run(Thread.java:745)
Caused by: javax.persistence.PersistenceException: org.hibernate.exception.JDBCConnectionException: Unable to acquire JDBC Connection
at org.hibernate.jpa.spi.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1692)
at org.hibernate.jpa.spi.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1602)
at org.hibernate.jpa.spi.AbstractEntityManagerImpl.throwPersistenceException(AbstractEntityManagerImpl.java:1700)
at org.hibernate.jpa.internal.TransactionImpl.begin(TransactionImpl.java:48)
at org.springframework.orm.jpa.vendor.HibernateJpaDialect.beginTransaction(HibernateJpaDialect.java:189)
at org.springframework.orm.jpa.JpaTransactionManager.doBegin(JpaTransactionManager.java:380)
... 9 more
Caused by: org.hibernate.exception.JDBCConnectionException: Unable to acquire JDBC Connection
at org.hibernate.exception.internal.SQLExceptionTypeDelegate.convert(SQLExceptionTypeDelegate.java:48)
at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:42)
at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:109)
at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:95)
at org.hibernate.resource.jdbc.internal.LogicalConnectionManagedImpl.acquireConnectionIfNeeded(LogicalConnectionManagedImpl.java:90)
at org.hibernate.resource.jdbc.internal.LogicalConnectionManagedImpl.getPhysicalConnection(LogicalConnectionManagedImpl.java:112)
at org.hibernate.resource.jdbc.internal.LogicalConnectionManagedImpl.getConnectionForTransactionManagement(LogicalConnectionManagedImpl.java:230)
at org.hibernate.resource.jdbc.internal.LogicalConnectionManagedImpl.begin(LogicalConnectionManagedImpl.java:237)
at org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl$TransactionDriverControlImpl.begin(JdbcResourceLocalTransactionCoordinatorImpl.java:214)
at org.hibernate.engine.transaction.internal.TransactionImpl.begin(TransactionImpl.java:52)
at org.hibernate.internal.SessionImpl.beginTransaction(SessionImpl.java:1512)
at org.hibernate.jpa.internal.TransactionImpl.begin(TransactionImpl.java:45)
... 11 more
Caused by: java.sql.SQLTransientConnectionException: HikariPool-1 - Connection is not available, request timed out after 30001ms.
at com.zaxxer.hikari.pool.HikariPool.createTimeoutException(HikariPool.java:591)
at com.zaxxer.hikari.pool.HikariPool.getConnection(HikariPool.java:194)
at com.zaxxer.hikari.pool.HikariPool.getConnection(HikariPool.java:146)
at com.zaxxer.hikari.HikariDataSource.getConnection(HikariDataSource.java:112)
at org.hibernate.engine.jdbc.connections.internal.DatasourceConnectionProviderImpl.getConnection(DatasourceConnectionProviderImpl.java:122)
at org.hibernate.internal.AbstractSessionImpl$NonContextualJdbcConnectionAccess.obtainConnection(AbstractSessionImpl.java:386)
at org.hibernate.resource.jdbc.internal.LogicalConnectionManagedImpl.acquireConnectionIfNeeded(LogicalConnectionManagedImpl.java:87)
... 18 more
[]

Answer 1

I noticed that you are injecting sessionFactory but not using spring-framework transaction features.
If you want to use like this you should close the session you are getting from sessionFactory in dao layer.