Hibernate - Query Hints

3.4.1.7. Query hints

Query hints (for performance optimization, usually) are implementation specific. Hints are declared using the query.setHint(String name, Object value) method, or through the @Named(Native)Query(hints) annotation Note that these are not SQL query hints! The Hibernate EJB3 implementation offers the following query hints:

Table 3.1. Hibernate query hints

Hint	Description
org.hibernate.timeout	Query timeout in seconds ( eg. new Integer(10) )
org.hibernate.fetchSize	Number of rows fetched by the JDBC driver per roundtrip ( eg. new Integer(50) )
org.hibernate.comment	Add a comment to the SQL query, useful for the DBA ( e.g. new String("fetch all orders in 1 statement") )
org.hibernate.cacheable	Whether or not a query is cacheable ( eg. new Boolean(true) ), defaults to false
org.hibernate.cacheMode	Override the cache mode for this query ( eg. CacheMode.REFRESH )
org.hibernate.cacheRegion	Cache region of this query ( eg. new String("regionName") )
org.hibernate.readOnly	Entities retrieved by this query will be loaded in a read-only mode where Hibernate will never dirty-check them or make changes persistent ( eg. new Boolean(true) ), default to false
org.hibernate.flushMode	Flush mode used for this query
org.hibernate.cacheMode	Cache mode used for this query

The value object accept both the native type or its string equivalent (eg. CaheMode.REFRESH or “REFRESH”). Please refer to the Hibernate reference documentation for more information.