galak-fyyar / hibernate-dsc

Hibernate Dynamic SQL Cache module - allows to keep sql cache up-to-date

#Hibernate Dynamic SQL Cache Overview

Dynamic Sql Cache module for Hibernate 4+.

This project used by author in several projects some of them high loaded systems. The reason to create it is inefficient Hibernate query caching mechanism:

1. HQL-cache including entity-collections cache, clearing on every UPDATE, INSERT or DELETE performed on any entity-table used in hql-query or entity-collection. It nullifies the benefits of using HQL-cache and entity-collection cache in high loaded systems.
2. SQL-cache holds result of first query invocation only and holds it forever, there is no way to reset it.

Therefore idea to create dynamic updatable SQL-cache was born. Query cache result updates on every INSERT or DELETE operation for entity-table used in SQL-query. To take advantage of dynamic sql cache you should change your look towards sql-query creation, and use sql-queries instead of any entity-collections too:

1. Query should result only entity ID, because you can always load it from entity-cache by ID. (Two cache read operations much faster than database reading operation)
2. Use only immutable properties of entity as query parameters.
3. Use sql-query with dynamic cache instead of any entity-collections.

Licensed under the Apache License 2.0.

Features

• Compatible with any cache provider (EHCache, Infinispan, Hazelcast ...)
• Test cases included

#Usage example

This example uses "Spring Framework", but you can use project without it.

Somethere in hibernate.cfg.xml

  ...

  <property name="hibernate.cache.query_cache_factory">com.corundumstudio.hibernate.dsc.DynamicQueryCacheFactory</property>

  <property name="hibernate.cache.region.factory_class">org.hibernate.cache.infinispan.InfinispanRegionFactory</property>
  <property name="hibernate.cache.use_second_level_cache">true</property>
  <property name="hibernate.cache.use_query_cache">true</property>

  ...

Note: you can use any other cache factory not only org.hibernate.cache.infinispan.InfinispanRegionFactory

@Configuration
public class QueryCacheListenerConfig {

    @Bean
    public QueryCacheEntityListener createCacheListener() {
            return new QueryCacheEntityListener();		
    }

    @PostConstruct
    protected void init() {

            // register hibernate dynamic cache listener
            // QueryCacheEntityListener

            EventListenerRegistry registry = sessionFactory.getServiceRegistry().getService(EventListenerRegistry.class);
            registry.getEventListenerGroup(EventType.POST_UPDATE).appendListener(createCacheListener());
            registry.getEventListenerGroup(EventType.POST_INSERT).appendListener(createCacheListener());
            registry.getEventListenerGroup(EventType.POST_DELETE).appendListener(createCacheListener());
    }

}

Entity DAO example:

@Service
public class SimpleEntityDao {

    private final String queryRegionName = "SimpleEntity_Query";
    private final String query = "SELECT id FROM SimpleEntity WHERE phone = :phone";

    @Autowired
    private QueryCacheEntityListener queryListener;
    @Autowired
    private SessionFactory sessionFactory;

    @PostConstruct
    protected void init() {

            // here is our cache callback
            // invokes on every "insert" or "delete" operation 
            // for SimpleEntity object and keeps query result up-to-date

    	CacheCallback<SimpleEntity> handler = new CacheCallback<SimpleEntity>() {

    		@Override
    		protected void onInsertOrDelete(InsertOrDeleteCommand command,
    				SimpleEntity object) {
    			command.setParameter("phone", object.getPhone());
    			command.setUniqueResult(object.getId());
    		}

    	};
    	queryCacheEntityListener.register(SimpleEntity.class, queryRegionName, handler);
    }
    
    @Transactional
    public SimpleEntity getEntityByPhone(String phone) {
            Session session = sessionFactory.getCurrentSession();
            SQLQuery sqlQuery = session.createSQLQuery(query);
            sqlQuery.addScalar("id", LongType.INSTANCE);
            sqlQuery.setCacheable(true);
            sqlQuery.setCacheRegion(cacheRegionName);
            sqlQuery.setParameter("phone", phone);
            Long idResult = (Long) sqlQuery.uniqueResult();      
            return session.get(SimpleEntity.class, idResult);
    }

    ...
    
    create, delete methods...

}