Melee Numerique 2022 - Revolutionize Java DB App Dev with Reactive Streams and Virtual Threads
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The document discusses how to revolutionize Java database application development with reactive streams and virtual threads when accessing Oracle Database. It introduces two solutions - reactive programming using R2DBC, Oracle JDBC Reactive Extensions and reactive streams libraries, and using virtual threads as supported by Project Loom and the Oracle JDBC driver. Demos are provided of these approaches.
Melee Numerique 2022 - Revolutionize Java DB App Dev with Reactive Streams and Virtual Threads
- 1. Revolutionize Java Database App Development with Reactive Streams and Virtual Threads
- 2. Juarez Barbosa Junior - @juarezjunior • Sr. Principal Java Developer Evangelist • 27 years of experience • SW Engineering, Developer Relations • Microsoft, Oracle, IBM, Nokia, Unisys, Accenture, and a few startups • Microsoft Azure Developer Relations Lead • IBM Watson Tech Evangelist & Cloud Rockstar • IBM Mobile Tech Evangelist & Global Thought Leader • Nokia Developers Global Champion • Lead Software/DevOps Architect • Expertise • Java, Cloud, DevOps, Blockchain About me
- 3. Java App Dev with Oracle Database • Language Comprehensive Programming Language and Framework Support • Mission Critical Simple Mission Critical Application Development • Cloud-native Seamless cloud-native application development • IDE Support Plugins for popular IDEs with Oracle Database and OCI support Oracle Database
- 4. Summary of Oracle DB Access with Java User Java Code JDBC Reactive Extension Standard JDBC API R2DBC + 3rd party Reactive Streams Libraries Async call with non-blocking backpressure operators (map, reduce, filters), concurrency modeling, monitoring, tracing Implements Java SE reactive stream interface (Flow) Full Reactive Streams Sync/blocking JDBC calls Java Business Logic User Java code Oracle Database Oracle JDBC driver VTs/lightweight JDBC calls
- 5. ⚫ Reactive Programming − Asynchronous database access with non-blocking network I/O − Oracle R2DBC + Oracle JDBC Reactive Extensions + Oracle Reactive Streams Ingestion − Application call stack must be fully asynchronous − Libraries are here to support it: Reactor, RxJava, Akka, Vert.x ⚫ Project Loom/Virtual Threads − Synchronous database access with lightweight threads − Standard JDBC + Virtual Threads − Client application call stack may use conventional (synchronous) code − Libraries must be compatible with Virtual Threads − Oracle instrumented the Oracle JDBC 21c driver to support Virtual Threads Two Solutions : Oracle JDBC Supports Both
- 6. ⚫ Blocking Threads ⚫ A JDBC call blocks a thread for 100’s of milliseconds (thread-per-request style) ⚫ Thread count increases linearly with the number of JDBC calls ⚫ Performance degrades as the number of threads increases ⚫ 1 MB of stack memory per thread ⚫ Scheduling many platform threads on a single CPU is expensive ⚫ Reactive Programming ⚫ Multiple threads are required when handling an async request ⚫ Async calls are executed in different threads -> hard to debug them ⚫ Paradigm shift requires upskilling efforts ⚫ Hard to maintain The Problem: Classic Java Platform Threads
- 7. The Solution: Virtual Threads ⚫ JEP 425: Virtual Threads (JDK 19 - Preview API) ⚫ Lightweight threads that dramatically reduce the effort of writing, maintaining, and observing high-throughput concurrent applications ⚫ VTs enable applications written in the simple thread-per-request style to scale with near- optimal hardware utilization ⚫ VTs enable existing code that uses the java.lang.Thread API to adopt virtual threads with minimal change ⚫ VTs enable easy troubleshooting, debugging, and profiling of virtual threads with existing JDK tools ⚫ VTs do not remove the traditional implementation of threads ⚫ VTs do not alter the basic concurrency model of Java
- 8. ⚫ Demo #1: Virtual Threads − Oracle JDBC Driver 21c instrumented to support Virtual Threads − API is Oracle JDBC with the Java SE library (Executor, ThreadFactory) − JEP 425 Virtual Threads (Project Loom – Preview API) − Runs on Java 19 Demos
- 9. Reactive JDBC - Synchronous vs Asynchronous JDBC Setup Blocking Handle Result Setup Non-Blocking Handle Result Synchronous JDBC Setup Blocking Handle Result Setup Non-Blocking Handle Result Setup Non-Blocking Handle Result Reactive JDBC Database Setup Blocking Handle Result Database
- 10. From Synchronous to Reactive JDBC: Query static String queryJdbc(java.sql.Connection connection) throws SQLException { try (java.sql.Statement statement = connection.createStatement()) { ResultSet resultSet = statement.executeQuery("SELECT 'Hello, JDBC!' FROM sys.dual"); if (resultSet.next()) return resultSet.getString(1); else throw new NoSuchElementException("Query returned zero rows"); } } static Publisher<String> queryR2dbc(io.r2dbc.spi.Connection connection) { return Flux.from(connection.createStatement( "SELECT 'Hello, R2DBC!' FROM sys.dual") .execute()) .flatMap(result -> result.map(row -> row.get(0, String.class))) .switchIfEmpty(Flux.error( new NoSuchElementException("Query returned zero rows"))); }
- 11. ⚫ Demo #1: Reactive JDBC − API is Oracle R2DBC with a reactive streams library − Demo uses Project Reactor. Could use RxJava, Akka, or any RS library − Runs on Java 11+ Demos
- 12. References • R2DBC • Oracle R2DBC Driver – https://github.com/oracle/oracle-r2dbc • JDK 19 / Project Loom • JDK 19 - https://openjdk.org/projects/jdk/19/ • Loom - https://openjdk.org/projects/loom/ • JEP 425 Virtual Threads (Preview) - https://bugs.openjdk.org/browse/JDK-8277131 • Develop Java applications with Oracle Database • JDBC – https://www.oracle.com/database/technologies/appdev/jdbc.html • Reactive Streams Ingestion Library • RSI – https://docs.oracle.com/en/database/oracle/oracle- database/21/jarsi/oracle/rsi/package-summary.html • https://medium.com/oracledevs/getting-started-with-the-java-library-for-reactive-streams- ingestion-rsi-afbc808e6e24
- 14. Reactive Streams Ingestion Library Java Program Reactive Streams Ingestion Library Direct Path Insert Thread Scheduling Record Grouping and Routing UCP Pooling and Routing (Shard & Rac) 1 2 3 4
- 15. ⚫ Demo #3: Reactive Streams Ingestion Library − API is Oracle Reactive Streams Ingestion Library − Leverages Oracle Direct Path Insert − Optimized CPU allocation − Record Grouping and Routing Demos
- 16. Poll Pick one or more options that may describe your situation: • Not concerned by thread counts/throughput • Not using reactive, waiting for Project Loom (Virtual Threads) • Interested in, or already using a reactive framework (Reactor, RxJava) • Interested in, or already using R2DBC • Interested in, or already using Oracle JDBC Reactive Extensions • Interested in, or already using Oracle Reactive Streams Ingestion (RSI)