Unable to acquire JDBC Connection

Question

I have a Spring Boot project with Hibernate and Hikari DataSource. If i have some functionality with injected SessionFactory object to get session object, in few days I have such exception for any methods assosiated with db operations (only restarting solves this problem):

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
......
Caused by: java.sql.SQLTransientConnectionException: HikariPool-1 - 
Connection is not available, request timed out after 30001ms.

It seems to manual used session makes this problem. (I have similar project with the same configs and functionality, but without injected SessionFactory and Session...and I don't have such problem at all)

application.yaml:

spring:
  jpa:
    properties:
      hibernate:
        dialect : org.hibernate.dialect.PostgreSQLDialect
        current_session_context_class: org.springframework.orm.hibernate5.SpringSessionContext

DataSourceConfig

@EnableJpaRepositories("com.my.project.config")
@Configuration
public class DataSourceConfig {

    @Inject
    private AppProperties properties;

    @Bean(name = "dataSource")
    public DataSource dataSource() {
        AppProperties.DatabaseProperties dbProps = properties.getDatabaseProperties();
        HikariDataSource dataSource = new HikariDataSource();
        dataSource.setDriverClassName(org.postgresql.Driver.class.getName());
        dataSource.setJdbcUrl(
            dbProps.getProtocol().concat("://")
                .concat(dbProps.getDbHost()).concat(":")
                .concat(dbProps.getDbPort()).concat("/")
                .concat(dbProps.getDbname())
        );
        dataSource.setUsername(dbProps.getUsername());
        dataSource.setPassword(dbProps.getPassword());
        dataSource.setMaximumPoolSize(30);
        dataSource.setMinimumIdle(30);

        return dataSource;
    }

    @Bean
    public SessionFactory sessionFactory(HibernateEntityManagerFactory hemf)   {
        return hemf.getSessionFactory();
    }
}

LogRepositoryImpl

@Repository
public class LogRepositoryImpl implements LogRepository {

    @Autowired
    private SessionFactory sessionFactory;

    @Override
    public List<Log> getLogs(int offset, int count) {
        Criteria criteria = getSession().createCriteria(Log.class);
        return criteria.setFirstResult(offset).setMaxResults(count).list();
    }

    @Override
    public void save(Log log) {
        getSession().save(log);
    }

    private Session getSession() {
        return sessionFactory.getCurrentSession();
    }
}

dataSource.setMaximumPoolSize(30), dataSource.setMinimumIdle(); didn't solve this problem

Answer 1

Sounds to me like an issue with your transaction boundaries, which aren't releasing the connections back to the pool. Could you try putting @Transactional on your LogRepositoryImpl class?

@Repository
@Transactional
public class LogRepositoryImpl implements LogRepository {
    . . . 
}