High-Performance Hibernate Devoxx France 2016
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This document discusses database performance optimization techniques when using Hibernate. It covers topics like connection management, identifier generation strategies, batching, fetching strategies, caching. The key message is that database access time consists of several components like connection acquisition, data access logic, statement submission/execution, result fetching. Optimizing these areas can significantly improve performance.
High-Performance Hibernate Devoxx France 2016
- 1. #DevoxxFR
- 2. #DevoxxFR • Hibernate Developer Advocate • vladmihalcea.com • @vlad_mihalcea
- 3. #DevoxxFR “More than half of application performance bottlenecks originate in the database” AppDynamics - http://www.appdynamics.com/database/
- 4. #DevoxxFR • Connection acquisition time • Data access logic (e.g. entity state transitions) • Statements submission time • Statements execution time • Result set fetching time • Idle time prior to releasing the database connection 𝑇 = 𝑡 𝑎𝑐𝑞 + 𝑡 𝑑𝑎𝑙 + 𝑡 𝑟𝑒𝑞 + 𝑡 𝑒𝑥𝑒𝑐 + 𝑡 𝑟𝑒𝑠 + 𝑡𝑖𝑑𝑙𝑒
- 5. #DevoxxFR • Connection providers • Identifier generators • Relationships • Batching • Fetching • Caching
- 6. #DevoxxFR
- 7. #DevoxxFR 𝑇 = 𝑡 𝑎𝑐𝑞 + 𝑡 𝑑𝑎𝑙 + 𝑡 𝑟𝑒𝑞 + 𝑡 𝑒𝑥𝑒𝑐 + 𝑡 𝑟𝑒𝑠 + 𝑡𝑖𝑑𝑙𝑒
- 8. #DevoxxFR • Connections acquired lazily • The shorter the transaction lifespan, the higher the transaction throughput
- 9. #DevoxxFR
- 10. #DevoxxFR 10 50 100 500 1000 5000 10000 0 200 400 600 800 1000 1200 1400 Statement count Time(ms) After statement After transaction
- 11. #DevoxxFR <property name="hibernate.connection.release_mode" value="after_transaction"/> • For JTA (e.g. Java EE), try this setting:
- 12. #DevoxxFR • AUTO (IDENTITY or SEQUENCE) • IDENTITY • SEQUENCE • TABLE 𝑇 = 𝑡 𝑎𝑐𝑞 + 𝑡 𝑑𝑎𝑙 + 𝑡 𝑟𝑒𝑞 + 𝑡 𝑒𝑥𝑒𝑐 + 𝑡 𝑟𝑒𝑠 + 𝑡𝑖𝑑𝑙𝑒
- 13. #DevoxxFR • Default for SQL Server and MySQL when using AUTO • Disables JDBC batch inserts
- 14. #DevoxxFR • Default for Oracle and PostgreSQL when using AUTO • May use roundtrip optimizers: hi/lo, pooled, pooled-lo • Hibernate 5 uses the enhanced sequence generator by default <property name="hibernate.id.new_generator_mappings" value="true"/>
- 15. #DevoxxFR 1 5 10 50 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 Sequence increment size Time(ms)
- 16. #DevoxxFR • Uses row-level locks and a separate transaction/connection • May use roundtrip optimizers: hi/lo, pooled, pooled-lo • Hibernate 5 uses the enhanced table generator by default <property name="hibernate.id.new_generator_mappings" value="true"/>
- 17. #DevoxxFR 1 5 10 50 0 0.5 1 1.5 2 2.5 3 Table increment size Time(ms)
- 18. #DevoxxFR • Identity makes no use of batch inserts • Table generator using an increment size of 100
- 19. #DevoxxFR 1 2 4 8 16 0 500 1000 1500 2000 2500 Thread count Time(ms) Identity Table
- 20. #DevoxxFR • Both generators use an increment size of 100 1 2 4 8 16 0 200 400 600 800 1000 1200 Thread count Time(ms) Sequence Table
- 21. #DevoxxFR 𝑇 = 𝑡 𝑎𝑐𝑞 + 𝑡 𝑑𝑎𝑙 + 𝑡 𝑟𝑒𝑞 + 𝑡 𝑒𝑥𝑒𝑐 + 𝑡 𝑟𝑒𝑠 + 𝑡𝑖𝑑𝑙𝑒
- 22. #DevoxxFR <property name="hibernate.jdbc.batch_size" value="10"/> • SessionFactory configuration • Plan to support Session-level batch size configuration 𝑇 = 𝑡 𝑎𝑐𝑞 + 𝑡 𝑑𝑎𝑙 + 𝑡 𝑟𝑒𝑞 + 𝑡 𝑒𝑥𝑒𝑐 + 𝑡 𝑟𝑒𝑠 + 𝑡𝑖𝑑𝑙𝑒
- 23. #DevoxxFR 1 10 20 30 40 50 60 70 80 90 100 1000 0 200 400 600 800 1000 1200 1400 1600 Batch size Time(ms) DB_A DB_B DB_C DB_D
- 24. #DevoxxFR 1 10 20 30 40 50 60 70 80 90 100 1000 0 100 200 300 400 500 600 700 Batch size Time(ms) DB_A DB_B DB_C DB_D
- 25. #DevoxxFR 1 10 20 30 40 50 60 70 80 90 100 1000 0 200 400 600 800 1000 1200 Batch size Time(ms) DB_A DB_B DB_C DB_D
- 26. #DevoxxFR <property name="hibernate.order_inserts" value="true"/> <property name="hibernate.order_updates" value="true"/> • Plan to support delete statement ordering too
- 27. #DevoxxFR <property name="hibernate.jdbc.batch_versioned_data" value="true"/> • Enabled by default in Hibernate 5 • Disabled in Hibernate 3 and 4, Oracle 8i, 9i, and 10g dialects.
- 28. #DevoxxFR • JDBC fetch size • JDBC ResultSet size • DTO vs Entity queries • Association fetching 𝑇 = 𝑡 𝑎𝑐𝑞 + 𝑡 𝑑𝑎𝑙 + 𝑡 𝑟𝑒𝑞 + 𝑡 𝑒𝑥𝑒𝑐 + 𝑡 𝑟𝑒𝑠 + 𝑡𝑖𝑑𝑙𝑒
- 29. #DevoxxFR • Oracle – Default fetch size is 10 • SQL Server – Adaptive buffering • PostgreSQL, MySQL – Fetch the whole ResultSet at once • SessionFactory setting: <property name="hibernate.jdbc.fetch_size" value="100"/>
- 30. #DevoxxFR • Query-level fetch size setting List<PostCommentSummary> summaries = entityManager.createQuery( "select new PostCommentSummary( " + " p.id, p.title, c.review ) " + "from PostComment c " + "join c.post p") .setHint(QueryHints.HINT_FETCH_SIZE, fetchSize) .getResultList();
- 31. #DevoxxFR 1 10 100 1000 10000 0 100 200 300 400 500 600 Fetch size Time(ms) DB_A DB_B DB_C DB_D
- 32. #DevoxxFR • Hibernate SQL-level limiting (works for native queries too!) List<PostCommentSummary> summaries = entityManager.createQuery( "select new PostCommentSummary( " + " p.id, p.title, c.review ) " + "from PostComment c " + "join c.post p") .setFirstResult(pageStart) .setMaxResults(pageSize) .getResultList();
- 33. #DevoxxFR • 100k Post(s) and + 1M PostComment(s) vs 100 entries Fetch all Fetch limit 0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 Time(ms) DB_A DB_B DB_C DB_D
- 34. #DevoxxFR SELECT * FROM post_comment pc INNER JOIN post p ON p.id = pc.post_id INNER JOIN post_details pd ON p.id = pd.id SELECT pc.version FROM post_comment pc INNER JOIN post p ON p.id = pc.post_id INNER JOIN post_details pd ON p.id = pd.id • Selecting all columns vs selecting a custom projection
- 35. #DevoxxFR • 100 Post(s), 100 PostDetail(s) , and 1000 PostComment(s) All columns Custom projection 0 5 10 15 20 25 30 Time(ms) DB_A DB_B DB_C DB_D
- 36. #DevoxxFR • Read-only views • Tree structures (Recursive CTE) • Paginated Tables • Analytics (Window functions)
- 37. #DevoxxFR • Writing data • Web flows / Multi-request logical transactions • Application-level repeatable reads • Detached entities / PersistenceContextType.EXTENDED • Optimistic concurrency control (e.g. version, dirty properties)
- 38. #DevoxxFR
- 39. #DevoxxFR “You can turn a Lazy into an Eager, but you cannot turn an Eager into a Lazy”
- 40. #DevoxxFR • Default to FetchType.LAZY • Fetch directive in JPQL/Criteria API queries • Entity graphs / @FetchProfile • LazyInitializationException
- 41. #DevoxxFR
- 42. #DevoxxFR <property name="hibernate.enable_lazy_load_no_trans" value="true"/> • “Band aid” for LazyInitializationException • One temporary Session/Connection for every lazily fetched association
- 43. #DevoxxFR 𝑇 = 𝑡 𝑎𝑐𝑞 + 𝑡 𝑑𝑎𝑙 + 𝑡 𝑟𝑒𝑞 + 𝑡 𝑒𝑥𝑒𝑐 + 𝑡 𝑟𝑒𝑠 + 𝑡𝑖𝑑𝑙𝑒
- 44. #DevoxxFR
- 45. #DevoxxFR “There are only two hard things in Computer Science: cache invalidation and naming things.” Phil Karlton
- 46. #DevoxxFR
- 47. #DevoxxFR • Complement entity caching • Store only entity identifiers • Read-Through • Invalidation-based (Consistency over Performance)
- 48. #DevoxxFR
- 49. #DevoxxFR https://leanpub.com/high-performance-java-persistence 𝑇 = 𝑡 𝑎𝑐𝑞 + 𝑡 𝑑𝑎𝑙 + 𝑡 𝑟𝑒𝑞 + 𝑡 𝑒𝑥𝑒𝑐 + 𝑡 𝑟𝑒𝑠 + 𝑡𝑖𝑑𝑙𝑒