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Performance Tuning
with
JPA 2.1 and Hibernate
Thorben Janssen
Thorben Janssen (@thjanssen123), 23rd
October 2015
Thorben Janssen
• Independent author and trainer
• Senior developer and architect @ Qualitype GmbH
• CDI 2.0 expert group member
• Twitter: @thjanssen123
• Blog: www.thoughts-on-java.org
Thorben Janssen (@thjanssen123) Prague, 23rd
October 2015
Performance
Thorben Janssen (@thjanssen123) Prague, 23rd
October 2015
Performance
• Recognize performance problems as early as possible
• Typical causes for performance problems
• Solving performance problems
Thorben Janssen (@thjanssen123) Prague, 23rd
October 2015
Hibernate Statistics
Thorben Janssen (@thjanssen123) Prague, 23rd
October 2015
Hibernate Statistics
• Activate via system property
• hibernate.generate_statistics = true
• Configure logging
• org.hibernate.stat = DEBUG
Thorben Janssen (@thjanssen123) Prague, 23rd
October 2015
Hibernate Statistics
• 08:24:10,916 DEBUG [org.hibernate.stat.internal.ConcurrentStatisticsImpl]
(default task-1) HHH000117: HQL: SELECT a FROM Author a WHERE a.lastName
= :lastName, time: 6ms, rows: 1
Thorben Janssen (@thjanssen123) Prague, 23rd
October 2015
Time spend
for this query Number of
returned rows
Hibernate Statistics
08:08:04,960 INFO [org.hibernate.engine.internal.StatisticalLoggingSessionEventListener] (default
task-2) Session Metrics {
1191522 nanoseconds spent acquiring 4 JDBC connections;
433875 nanoseconds spent releasing 4 JDBC connections;
4404058 nanoseconds spent preparing 6 JDBC statements;
12458725 nanoseconds spent executing 6 JDBC statements;
0 nanoseconds spent executing 0 JDBC batches;
0 nanoseconds spent performing 0 L2C puts;
0 nanoseconds spent performing 0 L2C hits;
0 nanoseconds spent performing 0 L2C misses;
586896 nanoseconds spent executing 1 flushes (flushing a total of 2 entities and 2 collections);
39434974 nanoseconds spent executing 1 partial-flushes (flushing a total of 2 entities and 2
collections)
Thorben Janssen (@thjanssen123) Prague, 23rd
October 2015
Number of statements
Cache usage
Time spend for
statements
Typical causes for
performance problems
Thorben Janssen (@thjanssen123) Prague, 23rd
October 2015
Typical Causes
• Slow SELECT statements
• Wrong FetchType
• Load same data multiple times
Thorben Janssen (@thjanssen123) Prague, 23rd
October 2015
Slow SELECT-statements
Thorben Janssen (@thjanssen123) Prague, 23rd
October 2015
Slow SELECTs
• In general no „real“ JPA or Hibernate problem
• Check generated SQL
• Check execution plan of the statement
• Check indexes
• Optimize SELECT statement
• Consider to use a native query
Thorben Janssen (@thjanssen123) Prague, 23rd
October 2015
Native Query
• Reasons to use native queries:
• JPQL supports only a subset of SQL
• Database specific features
• Native queries return an Object[] for each row
• Needs to be mapped programmatically or declaratively
Thorben Janssen (@thjanssen123) Prague, 23rd
October 2015
SqlResultSetMapping
• Declarative mapping of query results
@SqlResultSetMapping(
name = "myResultMapping ",
entities = {@EntityResult(...), …},
classes= {@ConstructorResult (…), …},
columns = {@ColumnResult(…), …}
)
this.em.createNativeQuery(“Select …", "myResultMapping")
Thorben Janssen (@thjanssen123) Prague, 23rd
October 2015
SqlResultSetMapping
@SqlResultSetMapping(
name = "myResultMapping",
entities = {@EntityResult(
entityClass = Author.class,
fields = {
@FieldResult(name = "id", column = „autId"),
…}
),
…},
classes= {@ConstructorResult (…), …},
columns = {@ColumnResult(…), …}
)
Thorben Janssen (@thjanssen123) Prague, 23rd
October 2015
SqlResultSetMapping
@SqlResultSetMapping(
name = "myResultMapping",
entities = {@EntityResult(...), …},
classes= {@ConstructorResult(
targetClass = BookPublisherValue.class,
columns = {
@ColumnResult(name = "title"),
…}
),
…},
columns = {@ColumnResult(…), …}
)
Thorben Janssen (@thjanssen123) Prague, 23rd
October 2015
SqlResultSetMapping
@SqlResultSetMapping(
name = "myResultMapping",
entities = {@EntityResult(...), …},
classes= {@ConstructorResult(...), …},
columns = {@ColumnResult(
name = "bookCount",
type = Long.class),
…},
)
Thorben Janssen (@thjanssen123) Prague, 23rd
October 2015
FetchType
Thorben Janssen (@thjanssen123) Prague, 23rd
October 2015
FetchType
• Defines when the relationship will be fetched
• Static definition in entity mapping
@ManyToMany(mappedBy="authors", fetch = FetchType.EAGER)
private Set<Book> books;
Thorben Janssen (@thjanssen123) Prague, 23rd
October 2015
FetchType
• Lazy
• Relationship gets loaded at first access
• Default for to-many relationships
• Eager
• Loads relationships immediately
• Default for to-one relationships
Thorben Janssen (@thjanssen123) Prague, 23rd
October 2015
Recommendations
• To-many relationships
• Stick to the default mapping (FetchType.LAZY)
• Use eager fetching for specific queries, if required
• To-one relationships
• Check individually
• Default is fine in most of the cases
Thorben Janssen (@thjanssen123) Prague, 23rd
October 2015
Query Specific Fetching
Thorben Janssen (@thjanssen123) Prague, 23rd
October 2015
Query Specific Fetching
• Fetch all required entities with one query
• Fetch Joins
• @NamedEntityGraph
• EntityGraph
Thorben Janssen (@thjanssen123) Prague, 23rd
October 2015
Query Specific Fetching
Thorben Janssen (@thjanssen123) Prague, 23rd
October 2015
Fetch Join
Thorben Janssen (@thjanssen123) Prague, 23rd
October 2015
Fetch Join
• Use JOIN FETCH instead of JOIN in JPQL query
List<Author> authors = this.em.createQuery(
"SELECT DISTINCT a FROM Author a JOIN FETCH a.books b",
Author.class).getResultList();
Thorben Janssen (@thjanssen123) Prague, 23rd
October 2015
Fetch Join
• Advantages
• Relationships gets loaded in same query
• Disadvantages
• Requires a special query for each use case
• Creates cartesian product
Thorben Janssen (@thjanssen123) Prague, 23rd
October 2015
@NamedEntityGraph
Thorben Janssen (@thjanssen123) Prague, 23rd
October 2015
@NamedEntityGraph
• Introduced in JPA 2.1
• Declaratively defines a graph of entities which will be loaded
• Graph is query independent
Thorben Janssen (@thjanssen123) Prague, 23rd
October 2015
@NamedEntityGraph
• Define a @NamedEntityGraph
@NamedEntityGraph(
name = "graph.AuthorBooksReviews",
attributeNodes =
@NamedAttributeNode(value = "books")
)
Thorben Janssen (@thjanssen123) Prague, 23rd
October 2015
@NamedEntityGraph
• Define a @NamedEntityGraph
@NamedEntityGraph(
name = "graph.AuthorBooksReviews",
attributeNodes =
@NamedAttributeNode(value = "books", subgraph = "books"),
subgraphs =
@NamedSubgraph(
name = "books",
attributeNodes = @NamedAttributeNode("reviews")))
Thorben Janssen (@thjanssen123) Prague, 23rd
October 2015
@NamedEntityGraph
• Provide entity graph es hint
EntityGraph graph = this.em.getEntityGraph("graph.AuthorBooks");
this.em.createQuery("SELECT DISTINCT a FROM Author a")
.setHint("javax.persistence.loadgraph", graph);
Thorben Janssen (@thjanssen123) Prague, 23rd
October 2015
@NamedEntityGraph
• Fetch graph
• Eager loading for all elements of the graph
• Lazy loading for all other attributes
• Load graph
• Eager loading for all elements of the graph
• Loads all other attributes with their defined FetchType
• Hibernate always uses a load graph
• HHH-8776
Thorben Janssen (@thjanssen123) Prague, 23rd
October 2015
@NamedEntityGraph
• Advantages
• Relationships gets loaded in same query
• Definition of the graph is independent of the query
• Disadvantages
• Creates cartesian product
Thorben Janssen (@thjanssen123) Prague, 23rd
October 2015
EntityGraph
Thorben Janssen (@thjanssen123) Prague, 23rd
October 2015
EntityGraph
• Introduced in JPA 2.1
• Dynamic version of @NamedEntityGraph
• Definition via Java API
• Graph is query independent
Thorben Janssen (@thjanssen123) Prague, 23rd
October 2015
EntityGraph
• Define and use EntityGraph
EntityGraph graph = this.em.createEntityGraph(Author.class);
Subgraph<Book> bookSubGraph = graph.addSubgraph(Author_.books);
bookSubGraph.addSubgraph(Book_.reviews);
this.em.createQuery("SELECT DISTINCT a FROM Author a")
.setHint("javax.persistence.loadgraph", graph);
Thorben Janssen (@thjanssen123) Prague, 23rd
October 2015
EntityGraph
• Advantages
• Relationships gets loaded in same query
• Definition of the graph is independent of the query
• Dynamic creation at runtime
• Disadvantages
• Creates cartesian product
Thorben Janssen (@thjanssen123) Prague, 23rd
October 2015
Caching
Thorben Janssen (@thjanssen123) Prague, 23rd
October 2015
Caching
Thorben Janssen (@thjanssen123) Prague, 23rd
October 2015
1st
Level
Cache
Hibernate
Session
1st
Level
Cache
Hibernate
Session
2nd
Level
Cache
Query
Cache
DB
1st Level Cache
Thorben Janssen (@thjanssen123) Prague, 23rd
October 2015
1st Level Cache
• Activated by default
• Linked to the Hibernate session
• Stores all entities that were used within a session
• Transparent usage
Thorben Janssen (@thjanssen123) Prague, 23rd
October 2015
2nd Level Cache
Thorben Janssen (@thjanssen123) Prague, 23rd
October 2015
2nd Level Cache
• Session independent entity store
• Needs to be activated
• persistence.xml or EntityManagerFactory
• Transparent usage
• PersistenceProvider doesn‘t need to provide it
• Not always portable
Thorben Janssen (@thjanssen123) Prague, 23rd
October 2015
2nd Level Cache
• Shared Cache Mode
• ALL cache all entities
• NONE cache no entities
• ENABLE_SELECTIVE cache needs to be activated for specific entities
• DISABLE_SELECTIVE cache can be deactivated for specific entities
• UNSPECIFIED use default settings of the PersistenceProvider
Thorben Janssen (@thjanssen123) Prague, 23rd
October 2015
2nd Level Cache
• Cache configuration
• Cache Retrieve Mode
• How to read entities from the cache
• Cache Store Mode
• How to write entities to the cache
• Concurrency Strategy
• How to handle concurrent access
Thorben Janssen (@thjanssen123) Prague, 23rd
October 2015
Query Cache
Thorben Janssen (@thjanssen123) Prague, 23rd
October 2015
Query Cache
• Stores query results for a query and its parameters
• [„FROM Author WHERE id=?“, 1]  [1]
• Stores only entity references or scalars
• Always use together with 2nd Level Cache
Thorben Janssen (@thjanssen123) Prague, 23rd
October 2015
Query Cache
• Hibernate specific
• Stores query result session independent
• Needs to be activated
• persistence.xml: hibernate.cache.use_query_cache = true
• Activate caching for a specific query
org.hibernate.Query.setCacheable(true)
@NamedQuery(… hints = @QueryHint(name="org.hibernate.cacheable",
value="true"))
Thorben Janssen (@thjanssen123) Prague, 23rd
October 2015
Recommendations
• Only cache data that is seldom updated
• Always benchmark the application when adding or changing caching
• Use Query Cache together with 2nd Level Cache
• Configuration has to fit to each other
Thorben Janssen (@thjanssen123) Prague, 23rd
October 2015
Resources
Thorben Janssen (@thjanssen123) Prague, 23rd
October 2015
Resources
• JSR 338: JavaTM Persistence API, Version 2.1
http://download.oracle.com/otndocs/jcp/persistence-2_1-fr-eval-spec/index.html
• Hibernate Reference Documentation
http://docs.jboss.org/hibernate/orm/4.3/manual/en-US/html/
• Hibernate Developer Guide http://docs.jboss.org/hibernate/orm/4.3/devguide/en-
US/html/
• Hibernate ORM: Tips, Tricks and Performance Techniques by Brett Meyer
http://de.slideshare.net/brmeyer/hibernate-orm-performance-31550150
Thorben Janssen (@thjanssen123) Prague, 23rd
October 2015
Resources
• Java Persistence with Hibernate Second Edition by Christian Bauer, Gaving King, Gary
Gregory
• Java Platform, Enterprise Edition: The Java EE Tutorial
https://docs.oracle.com/javaee/7/tutorial/index.html
• Hibernate: Truly Understanding the Second-Level and Query Caches
http://www.javalobby.org/java/forums/t48846.html
Thorben Janssen (@thjanssen123) Prague, 23rd
October 2015
Presentation & Cheat
Sheet
Thorben Janssen (@thjanssen123) Prague, 23rd
October 2015
Presentation & Cheat Sheet
• Get this presentation and a handy cheat sheet with all the discussed performance
tuning tips at
http://www.thoughts-on-java.org/geecon2015/
Thorben Janssen (@thjanssen123) Prague, 23rd
October 2015

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Performance Tuning with JPA 2.1 and Hibernate (Geecon Prague 2015)

  • 1. Performance Tuning with JPA 2.1 and Hibernate Thorben Janssen Thorben Janssen (@thjanssen123), 23rd October 2015
  • 2. Thorben Janssen • Independent author and trainer • Senior developer and architect @ Qualitype GmbH • CDI 2.0 expert group member • Twitter: @thjanssen123 • Blog: www.thoughts-on-java.org Thorben Janssen (@thjanssen123) Prague, 23rd October 2015
  • 4. Performance • Recognize performance problems as early as possible • Typical causes for performance problems • Solving performance problems Thorben Janssen (@thjanssen123) Prague, 23rd October 2015
  • 5. Hibernate Statistics Thorben Janssen (@thjanssen123) Prague, 23rd October 2015
  • 6. Hibernate Statistics • Activate via system property • hibernate.generate_statistics = true • Configure logging • org.hibernate.stat = DEBUG Thorben Janssen (@thjanssen123) Prague, 23rd October 2015
  • 7. Hibernate Statistics • 08:24:10,916 DEBUG [org.hibernate.stat.internal.ConcurrentStatisticsImpl] (default task-1) HHH000117: HQL: SELECT a FROM Author a WHERE a.lastName = :lastName, time: 6ms, rows: 1 Thorben Janssen (@thjanssen123) Prague, 23rd October 2015 Time spend for this query Number of returned rows
  • 8. Hibernate Statistics 08:08:04,960 INFO [org.hibernate.engine.internal.StatisticalLoggingSessionEventListener] (default task-2) Session Metrics { 1191522 nanoseconds spent acquiring 4 JDBC connections; 433875 nanoseconds spent releasing 4 JDBC connections; 4404058 nanoseconds spent preparing 6 JDBC statements; 12458725 nanoseconds spent executing 6 JDBC statements; 0 nanoseconds spent executing 0 JDBC batches; 0 nanoseconds spent performing 0 L2C puts; 0 nanoseconds spent performing 0 L2C hits; 0 nanoseconds spent performing 0 L2C misses; 586896 nanoseconds spent executing 1 flushes (flushing a total of 2 entities and 2 collections); 39434974 nanoseconds spent executing 1 partial-flushes (flushing a total of 2 entities and 2 collections) Thorben Janssen (@thjanssen123) Prague, 23rd October 2015 Number of statements Cache usage Time spend for statements
  • 9. Typical causes for performance problems Thorben Janssen (@thjanssen123) Prague, 23rd October 2015
  • 10. Typical Causes • Slow SELECT statements • Wrong FetchType • Load same data multiple times Thorben Janssen (@thjanssen123) Prague, 23rd October 2015
  • 11. Slow SELECT-statements Thorben Janssen (@thjanssen123) Prague, 23rd October 2015
  • 12. Slow SELECTs • In general no „real“ JPA or Hibernate problem • Check generated SQL • Check execution plan of the statement • Check indexes • Optimize SELECT statement • Consider to use a native query Thorben Janssen (@thjanssen123) Prague, 23rd October 2015
  • 13. Native Query • Reasons to use native queries: • JPQL supports only a subset of SQL • Database specific features • Native queries return an Object[] for each row • Needs to be mapped programmatically or declaratively Thorben Janssen (@thjanssen123) Prague, 23rd October 2015
  • 14. SqlResultSetMapping • Declarative mapping of query results @SqlResultSetMapping( name = "myResultMapping ", entities = {@EntityResult(...), …}, classes= {@ConstructorResult (…), …}, columns = {@ColumnResult(…), …} ) this.em.createNativeQuery(“Select …", "myResultMapping") Thorben Janssen (@thjanssen123) Prague, 23rd October 2015
  • 15. SqlResultSetMapping @SqlResultSetMapping( name = "myResultMapping", entities = {@EntityResult( entityClass = Author.class, fields = { @FieldResult(name = "id", column = „autId"), …} ), …}, classes= {@ConstructorResult (…), …}, columns = {@ColumnResult(…), …} ) Thorben Janssen (@thjanssen123) Prague, 23rd October 2015
  • 16. SqlResultSetMapping @SqlResultSetMapping( name = "myResultMapping", entities = {@EntityResult(...), …}, classes= {@ConstructorResult( targetClass = BookPublisherValue.class, columns = { @ColumnResult(name = "title"), …} ), …}, columns = {@ColumnResult(…), …} ) Thorben Janssen (@thjanssen123) Prague, 23rd October 2015
  • 17. SqlResultSetMapping @SqlResultSetMapping( name = "myResultMapping", entities = {@EntityResult(...), …}, classes= {@ConstructorResult(...), …}, columns = {@ColumnResult( name = "bookCount", type = Long.class), …}, ) Thorben Janssen (@thjanssen123) Prague, 23rd October 2015
  • 18. FetchType Thorben Janssen (@thjanssen123) Prague, 23rd October 2015
  • 19. FetchType • Defines when the relationship will be fetched • Static definition in entity mapping @ManyToMany(mappedBy="authors", fetch = FetchType.EAGER) private Set<Book> books; Thorben Janssen (@thjanssen123) Prague, 23rd October 2015
  • 20. FetchType • Lazy • Relationship gets loaded at first access • Default for to-many relationships • Eager • Loads relationships immediately • Default for to-one relationships Thorben Janssen (@thjanssen123) Prague, 23rd October 2015
  • 21. Recommendations • To-many relationships • Stick to the default mapping (FetchType.LAZY) • Use eager fetching for specific queries, if required • To-one relationships • Check individually • Default is fine in most of the cases Thorben Janssen (@thjanssen123) Prague, 23rd October 2015
  • 22. Query Specific Fetching Thorben Janssen (@thjanssen123) Prague, 23rd October 2015
  • 23. Query Specific Fetching • Fetch all required entities with one query • Fetch Joins • @NamedEntityGraph • EntityGraph Thorben Janssen (@thjanssen123) Prague, 23rd October 2015
  • 24. Query Specific Fetching Thorben Janssen (@thjanssen123) Prague, 23rd October 2015
  • 25. Fetch Join Thorben Janssen (@thjanssen123) Prague, 23rd October 2015
  • 26. Fetch Join • Use JOIN FETCH instead of JOIN in JPQL query List<Author> authors = this.em.createQuery( "SELECT DISTINCT a FROM Author a JOIN FETCH a.books b", Author.class).getResultList(); Thorben Janssen (@thjanssen123) Prague, 23rd October 2015
  • 27. Fetch Join • Advantages • Relationships gets loaded in same query • Disadvantages • Requires a special query for each use case • Creates cartesian product Thorben Janssen (@thjanssen123) Prague, 23rd October 2015
  • 29. @NamedEntityGraph • Introduced in JPA 2.1 • Declaratively defines a graph of entities which will be loaded • Graph is query independent Thorben Janssen (@thjanssen123) Prague, 23rd October 2015
  • 30. @NamedEntityGraph • Define a @NamedEntityGraph @NamedEntityGraph( name = "graph.AuthorBooksReviews", attributeNodes = @NamedAttributeNode(value = "books") ) Thorben Janssen (@thjanssen123) Prague, 23rd October 2015
  • 31. @NamedEntityGraph • Define a @NamedEntityGraph @NamedEntityGraph( name = "graph.AuthorBooksReviews", attributeNodes = @NamedAttributeNode(value = "books", subgraph = "books"), subgraphs = @NamedSubgraph( name = "books", attributeNodes = @NamedAttributeNode("reviews"))) Thorben Janssen (@thjanssen123) Prague, 23rd October 2015
  • 32. @NamedEntityGraph • Provide entity graph es hint EntityGraph graph = this.em.getEntityGraph("graph.AuthorBooks"); this.em.createQuery("SELECT DISTINCT a FROM Author a") .setHint("javax.persistence.loadgraph", graph); Thorben Janssen (@thjanssen123) Prague, 23rd October 2015
  • 33. @NamedEntityGraph • Fetch graph • Eager loading for all elements of the graph • Lazy loading for all other attributes • Load graph • Eager loading for all elements of the graph • Loads all other attributes with their defined FetchType • Hibernate always uses a load graph • HHH-8776 Thorben Janssen (@thjanssen123) Prague, 23rd October 2015
  • 34. @NamedEntityGraph • Advantages • Relationships gets loaded in same query • Definition of the graph is independent of the query • Disadvantages • Creates cartesian product Thorben Janssen (@thjanssen123) Prague, 23rd October 2015
  • 35. EntityGraph Thorben Janssen (@thjanssen123) Prague, 23rd October 2015
  • 36. EntityGraph • Introduced in JPA 2.1 • Dynamic version of @NamedEntityGraph • Definition via Java API • Graph is query independent Thorben Janssen (@thjanssen123) Prague, 23rd October 2015
  • 37. EntityGraph • Define and use EntityGraph EntityGraph graph = this.em.createEntityGraph(Author.class); Subgraph<Book> bookSubGraph = graph.addSubgraph(Author_.books); bookSubGraph.addSubgraph(Book_.reviews); this.em.createQuery("SELECT DISTINCT a FROM Author a") .setHint("javax.persistence.loadgraph", graph); Thorben Janssen (@thjanssen123) Prague, 23rd October 2015
  • 38. EntityGraph • Advantages • Relationships gets loaded in same query • Definition of the graph is independent of the query • Dynamic creation at runtime • Disadvantages • Creates cartesian product Thorben Janssen (@thjanssen123) Prague, 23rd October 2015
  • 39. Caching Thorben Janssen (@thjanssen123) Prague, 23rd October 2015
  • 40. Caching Thorben Janssen (@thjanssen123) Prague, 23rd October 2015 1st Level Cache Hibernate Session 1st Level Cache Hibernate Session 2nd Level Cache Query Cache DB
  • 41. 1st Level Cache Thorben Janssen (@thjanssen123) Prague, 23rd October 2015
  • 42. 1st Level Cache • Activated by default • Linked to the Hibernate session • Stores all entities that were used within a session • Transparent usage Thorben Janssen (@thjanssen123) Prague, 23rd October 2015
  • 43. 2nd Level Cache Thorben Janssen (@thjanssen123) Prague, 23rd October 2015
  • 44. 2nd Level Cache • Session independent entity store • Needs to be activated • persistence.xml or EntityManagerFactory • Transparent usage • PersistenceProvider doesn‘t need to provide it • Not always portable Thorben Janssen (@thjanssen123) Prague, 23rd October 2015
  • 45. 2nd Level Cache • Shared Cache Mode • ALL cache all entities • NONE cache no entities • ENABLE_SELECTIVE cache needs to be activated for specific entities • DISABLE_SELECTIVE cache can be deactivated for specific entities • UNSPECIFIED use default settings of the PersistenceProvider Thorben Janssen (@thjanssen123) Prague, 23rd October 2015
  • 46. 2nd Level Cache • Cache configuration • Cache Retrieve Mode • How to read entities from the cache • Cache Store Mode • How to write entities to the cache • Concurrency Strategy • How to handle concurrent access Thorben Janssen (@thjanssen123) Prague, 23rd October 2015
  • 47. Query Cache Thorben Janssen (@thjanssen123) Prague, 23rd October 2015
  • 48. Query Cache • Stores query results for a query and its parameters • [„FROM Author WHERE id=?“, 1]  [1] • Stores only entity references or scalars • Always use together with 2nd Level Cache Thorben Janssen (@thjanssen123) Prague, 23rd October 2015
  • 49. Query Cache • Hibernate specific • Stores query result session independent • Needs to be activated • persistence.xml: hibernate.cache.use_query_cache = true • Activate caching for a specific query org.hibernate.Query.setCacheable(true) @NamedQuery(… hints = @QueryHint(name="org.hibernate.cacheable", value="true")) Thorben Janssen (@thjanssen123) Prague, 23rd October 2015
  • 50. Recommendations • Only cache data that is seldom updated • Always benchmark the application when adding or changing caching • Use Query Cache together with 2nd Level Cache • Configuration has to fit to each other Thorben Janssen (@thjanssen123) Prague, 23rd October 2015
  • 51. Resources Thorben Janssen (@thjanssen123) Prague, 23rd October 2015
  • 52. Resources • JSR 338: JavaTM Persistence API, Version 2.1 http://download.oracle.com/otndocs/jcp/persistence-2_1-fr-eval-spec/index.html • Hibernate Reference Documentation http://docs.jboss.org/hibernate/orm/4.3/manual/en-US/html/ • Hibernate Developer Guide http://docs.jboss.org/hibernate/orm/4.3/devguide/en- US/html/ • Hibernate ORM: Tips, Tricks and Performance Techniques by Brett Meyer http://de.slideshare.net/brmeyer/hibernate-orm-performance-31550150 Thorben Janssen (@thjanssen123) Prague, 23rd October 2015
  • 53. Resources • Java Persistence with Hibernate Second Edition by Christian Bauer, Gaving King, Gary Gregory • Java Platform, Enterprise Edition: The Java EE Tutorial https://docs.oracle.com/javaee/7/tutorial/index.html • Hibernate: Truly Understanding the Second-Level and Query Caches http://www.javalobby.org/java/forums/t48846.html Thorben Janssen (@thjanssen123) Prague, 23rd October 2015
  • 54. Presentation & Cheat Sheet Thorben Janssen (@thjanssen123) Prague, 23rd October 2015
  • 55. Presentation & Cheat Sheet • Get this presentation and a handy cheat sheet with all the discussed performance tuning tips at http://www.thoughts-on-java.org/geecon2015/ Thorben Janssen (@thjanssen123) Prague, 23rd October 2015