3.4. Optional configuration properties

There are a number of other properties that control the behaviour of Hibernate at runtime. All are optional and have reasonable default values.
Warning: some of these properties are "system-level" only. System-level properties can be set only via java -Dproperty=value or hibernate.properties. They may not be set by the other techniques described above.

Table 3.3. Hibernate Configuration Properties

Property name Purpose
hibernate.dialect The classname of a Hibernate Dialect which allows Hibernate to generate SQL optimized for a particular relational database.
eg.full.classname.of.Dialect
hibernate.show_sql Write all SQL statements to console. This is an alternative to setting the log category org.hibernate.SQL to debug.
eg.true | false
hibernate.format_sql Pretty print the SQL in the log and console.
eg.true | false
hibernate.default_schema Qualify unqualified tablenames with the given schema/tablespace in generated SQL.
eg.SCHEMA_NAME
hibernate.default_catalog Qualify unqualified tablenames with the given catalog in generated SQL.
eg.CATALOG_NAME
hibernate.session_factory_name The SessionFactory will be automatically bound to this name in JNDI after it has been created.
eg.jndi/composite/name
hibernate.max_fetch_depth Set a maximum "depth" for the outer join fetch tree for single-ended associations (one-to-one, many-to-one). A 0 disables default outer join fetching.
eg. recommended values between 0 and 3
hibernate.default_batch_fetch_size Set a default size for Hibernate batch fetching of associations.
eg. recommended values 4, 8, 16
hibernate.default_entity_mode Set a default mode for entity representation for all sessions opened from this SessionFactory
dynamic-map, dom4j, pojo
hibernate.order_updates Force Hibernate to order SQL updates by the primary key value of the items being updated. This will result in fewer transaction deadlocks in highly concurrent systems.
eg.true | false
hibernate.generate_statistics If enabled, Hibernate will collect statistics useful for performance tuning.
eg.true | false
hibernate.use_identifer_rollback If enabled, generated identifier properties will be reset to default values when objects are deleted.
eg.true | false
hibernate.use_sql_comments If turned on, Hibernate will generate comments inside the SQL, for easier debugging, defaults to false.
eg.true | false

Table 3.4. Hibernate JDBC and Connection Properties

Property name Purpose
hibernate.jdbc.fetch_size A non-zero value determines the JDBC fetch size (calls Statement.setFetchSize()).
hibernate.jdbc.batch_size A non-zero value enables use of JDBC2 batch updates by Hibernate.
eg. recommended values between 5 and 30
hibernate.jdbc.batch_versioned_data Set this property to true if your JDBC driver returns correct row counts from executeBatch() (it is usually safe to turn this option on). Hibernate will then use batched DML for automatically versioned data. Defaults to false.
eg.true | false
hibernate.jdbc.factory_class Select a custom Batcher. Most applications will not need this configuration property.
eg.classname.of.Batcher
hibernate.jdbc.use_scrollable_resultset Enables use of JDBC2 scrollable resultsets by Hibernate. This property is only necessary when using user supplied JDBC connections, Hibernate uses connection metadata otherwise.
eg.true | false
hibernate.jdbc.use_streams_for_binary Use streams when writing/reading binary or serializable types to/from JDBC (system-level property).
eg.true | false
hibernate.jdbc.use_get_generated_keys Enable use of JDBC3 PreparedStatement.getGeneratedKeys() to retrieve natively generated keys after insert. Requires JDBC3+ driver and JRE1.4+, set to false if your driver has problems with the Hibernate identifier generators. By default, tries to determine the driver capabilites using connection metadata.
eg.true|false
hibernate.connection.provider_class The classname of a custom ConnectionProvider which provides JDBC connections to Hibernate.
eg.classname.of.ConnectionProvider
hibernate.connection.isolation Set the JDBC transaction isolation level. Check java.sql.Connection for meaningful values but note that most databases do not support all isolation levels.
eg.1, 2, 4, 8
hibernate.connection.autocommit Enables autocommit for JDBC pooled connections (not recommended).
eg.true | false
hibernate.connection.release_mode Specify when Hibernate should release JDBC connections. By default, a JDBC connection is held until the session is explicitly closed or disconnected. For an application server JTA datasource, you should use after_statement to aggressively release connections after every JDBC call. For a non-JTA connection, it often makes sense to release the connection at the end of each transaction, by using after_transaction. auto will choose after_statement for the JTA and CMT transaction strategies and after_transaction for the JDBC transaction strategy.
eg.auto (default) | on_close | after_transaction | after_statement
Note that this setting only affects Session s returned from SessionFactory.openSession. For Session s obtained through SessionFactory.getCurrentSession, the CurrentSessionContext implementation configured for use controls the connection release mode for those Session s. See Section 2.5, “Contextual Sessions”.
hibernate.connection.<propertyName> Pass the JDBC property propertyName to DriverManager.getConnection().
hibernate.jndi.<propertyName> Pass the property propertyName to the JNDI InitialContextFactory.

Table 3.5. Hibernate Cache Properties

Property name Purpose
hibernate.cache.provider_class The classname of a custom CacheProvider.
eg.classname.of.CacheProvider
hibernate.cache.use_minimal_puts Optimize second-level cache operation to minimize writes, at the cost of more frequent reads. This setting is most useful for clustered caches and, in Hibernate3, is enabled by default for clustered cache implementations.
eg.true|false
hibernate.cache.use_query_cache Enable the query cache, individual queries still have to be set cachable.
eg.true|false
hibernate.cache.use_second_level_cache May be used to completely disable the second level cache, which is enabled by default for classes which specify a <cache> mapping.
eg.true|false
hibernate.cache.query_cache_factory The classname of a custom QueryCache interface, defaults to the built-in StandardQueryCache.
eg.classname.of.QueryCache
hibernate.cache.region_prefix A prefix to use for second-level cache region names.
eg.prefix
hibernate.cache.use_structured_entries Forces Hibernate to store data in the second-level cache in a more human-friendly format.
eg.true|false

Table 3.6. Hibernate Transaction Properties

Property name Purpose
hibernate.transaction.factory_class The classname of a TransactionFactory to use with Hibernate Transaction API (defaults to JDBCTransactionFactory).
eg.classname.of.TransactionFactory
jta.UserTransaction A JNDI name used by JTATransactionFactory to obtain the JTA UserTransaction from the application server.
eg.jndi/composite/name
hibernate.transaction.manager_lookup_class The classname of a TransactionManagerLookup - required when JVM-level caching is enabled or when using hilo generator in a JTA environment.
eg.classname.of.TransactionManagerLookup
hibernate.transaction.flush_before_completion If enabled, the session will be automatically flushed during the before completion phase of the transaction. Built-in and automatic session context management is preferred, see Section 2.5, “Contextual Sessions”.
eg.true | false
hibernate.transaction.auto_close_session If enabled, the session will be automatically closed during the after completion phase of the transaction. Built-in and utomatic session context management is preferred, see Section 2.5, “Contextual Sessions”.
eg.true | false

Table 3.7. Miscellaneous Properties

Property name Purpose
hibernate.current_session_context_class Supply a (custom) strategy for the scoping of the "current" Session. See Section 2.5, “Contextual Sessions” for more information about the built-in strategies.
eg.jta | thread | managed | custom.Class
hibernate.query.factory_class Chooses the HQL parser implementation.
eg.org.hibernate.hql.ast.ASTQueryTranslatorFactory or org.hibernate.hql.classic.ClassicQueryTranslatorFactory
hibernate.query.substitutions Mapping from tokens in Hibernate queries to SQL tokens (tokens might be function or literal names, for example).
eg.hqlLiteral=SQL_LITERAL, hqlFunction=SQLFUNC
hibernate.hbm2ddl.auto Automatically validate or export schema DDL to the database when the SessionFactory is created. With create-drop, the database schema will be dropped when the SessionFactory is closed explicitly.
eg.validate | update | create | create-drop
hibernate.cglib.use_reflection_optimizer Enables use of CGLIB instead of runtime reflection (System-level property). Reflection can sometimes be useful when troubleshooting, note that Hibernate always requires CGLIB even if you turn off the optimizer. You can not set this property in hibernate.cfg.xml.
eg.true | false

3.4.1. SQL Dialects

You should always set the hibernate.dialect property to the correct org.hibernate.dialect.Dialect subclass for your database. If you specify a dialect, Hibernate will use sensible defaults for some of the other properties listed above, saving you the effort of specifying them manually.

Table 3.8. Hibernate SQL Dialects (hibernate.dialect)

RDBMS Dialect
DB2 org.hibernate.dialect.DB2Dialect
DB2 AS/400 org.hibernate.dialect.DB2400Dialect
DB2 OS390 org.hibernate.dialect.DB2390Dialect
PostgreSQL org.hibernate.dialect.PostgreSQLDialect
MySQL org.hibernate.dialect.MySQLDialect
MySQL with InnoDB org.hibernate.dialect.MySQLInnoDBDialect
MySQL with MyISAM org.hibernate.dialect.MySQLMyISAMDialect
Oracle (any version) org.hibernate.dialect.OracleDialect
Oracle 9i org.hibernate.dialect.Oracle9iDialect
Oracle 10g org.hibernate.dialect.Oracle10gDialect
Sybase org.hibernate.dialect.SybaseDialect
Sybase Anywhere org.hibernate.dialect.SybaseAnywhereDialect
Microsoft SQL Server org.hibernate.dialect.SQLServerDialect
SAP DB org.hibernate.dialect.SAPDBDialect
Informix org.hibernate.dialect.InformixDialect
HypersonicSQL org.hibernate.dialect.HSQLDialect
Ingres org.hibernate.dialect.IngresDialect
Progress org.hibernate.dialect.ProgressDialect
Mckoi SQL org.hibernate.dialect.MckoiDialect
Interbase org.hibernate.dialect.InterbaseDialect
Pointbase org.hibernate.dialect.PointbaseDialect
FrontBase org.hibernate.dialect.FrontbaseDialect
Firebird org.hibernate.dialect.FirebirdDialect