CloudTalks - Revolutionize Java DB AppDev with Reactive Streams and Virtual Threads
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The presentation discusses revolutionizing Java database application development with reactive streams and virtual threads. It covers Oracle JDBC support for the latest Java versions, an overview of accessing Oracle databases with Java, differences between synchronous and asynchronous JDBC, classic Java threads versus virtual threads, reactive JDBC, reactive streams ingestion, and transitioning from synchronous to reactive JDBC using Oracle R2DBC. Live demos are provided comparing virtual threads to platform threads, reactive streams ingestion, and Oracle R2DBC.
CloudTalks - Revolutionize Java DB AppDev with Reactive Streams and Virtual Threads
- 1. Revolutionize Java Database App Development with Reactive Streams and Virtual Threads Cloud Talks by Cloud Conference Day Juarez Barbosa Junior - @juarezjunior November 2022 Copyright © 2022, Oracle and/or its affiliates
- 2. About me • Juarez Barbosa Junior - @juarezjunior • Senior 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, Cloud-native, Blockchain Copyright © 2022, Oracle and/or its affiliates
- 3. Agenda • Java App Dev with Oracle Database • Support for the Latest Java Versions • Overview of Oracle DB Access with Java • Oracle JDBC – Sync and Async • Classic Java Platform Threads • Project Loom – Virtual Threads • Virtual Threads - JEP 425 (Preview API) • Demo # 1: Virtual vs Platform Threads • Reactive JDBC - Synchronous vs Asynchronous JDBC • Reactive Streams Ingestion (RSI) • Demo # 2: Reactive Streams Ingestion (RSI) • From Sync to Reactive JDBC: Oracle R2DBC • Demo # 3: Oracle R2DBC • Live Labs/Free Oracle Cloud Account/Oracle ACE Program Copyright © 2022, Oracle and/or its affiliates
- 4. Copyright © 2022, Oracle and/or its affiliates Java App Dev with Oracle Database
- 5. Copyright © 2022, Oracle and/or its affiliates Support for the Latest Java Versions • Java 11 - native support, compiled with it • Java 17 - certified • JDBC Standards - 4.2 and 4.3 • JMS 1.1 - latest is 2.0 • GraalVM - native image instrumentation • Reactive Streams - Java Flow API support • Project Loom - Virtual Threads support • Data access is critical in mission-critical apps
- 6. Copyright © 2022, Oracle and/or its affiliates Overview 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
- 7. Copyright © 2022, Oracle and/or its affiliates Oracle JDBC – Sync and Async ⚫ 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
- 8. Copyright © 2022, Oracle and/or its affiliates Classic Java Platform Threads ⚫ 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 is expensive ⚫ Preemptive scheduling vs time-slicing
- 9. Copyright © 2022, Oracle and/or its affiliates Virtual Threads - JEP 425 (Preview API) ⚫ Virtual Threads ⚫ Lightweight threads that dramatically reduce the effort of writing, maintaining, and observing high-throughput concurrent applications ⚫ Enable applications written in the simple thread-per-request style to scale with near- optimal hardware utilization ⚫ Enable existing code that uses the java.lang.Thread API to adopt virtual threads with minimal change ⚫ Enable easy troubleshooting, debugging, and profiling of virtual threads with existing JDK tools ⚫ Do not remove the traditional implementation of threads ⚫ Do not alter the basic concurrency model of Java
- 10. Copyright © 2022, Oracle and/or its affiliates Demo # 1: Virtual vs Platform Threads ⚫ Virtual Threads versus Platform Threads ⚫ JEP 425 Virtual Threads (Project) ⚫ Runs on Java 19 (Preview API) ⚫ javac --release 19 --enable-preview ⚫ java --enable-preview ⚫ Comparison of OS resources consumption (Threads only + JDBC) ⚫ Oracle JDBC Driver 21c instrumented to support Virtual Threads ⚫ API is Oracle JDBC with the Java SE library (Executor, ThreadFactory)
- 11. Copyright © 2022, Oracle and/or its affiliates 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
- 12. Copyright © 2022, Oracle and/or its affiliates Reactive Streams Ingestion (RSI) ⚫ Java Library for Reactive Streams Ingestion ⚫ Streaming capability: Ingest data in an unblocking, and reactive way from a large group of clients ⚫ Group records through RAC (Real App Clusters), and Shard affinity using native UCP (Universal Connection Pool) ⚫ Optimize CPU allocation while decoupling record Processing from I/O ⚫ Fastest insert method for the Oracle Database through Direct Path Insert, bypassing SQL and writing directly into the DB files
- 13. Copyright © 2022, Oracle and/or its affiliates Demo # 2: Reactive Streams Ingestion (RSI) Container Pipelines, Jenkins, etc. Build Test Push Push Docker images to Registry Cloud Infrastructur e Registry Container Engine for Kubernetes Pull images from Registry Deploy images to production Kubernetes worker nodes Containers running microservices deployed over Kubernetes ORACLE CLOUD INFRASTRUCTURE ATP, ADW, ATP-D, AFDW-D Memoptimized Rowstore RSI Runtime: Non- blocking, optimized library for streaming data through Direct Path, Shard & RAC/FAN support. HTTP / REST Engine over Helidon Define build for CI/CD toolchain gRPC / AMQP / MQTT Engines Microservices Files / Logs IoT Devices / Apps cv MQTT gRPC AMQP HTTP / REST JDBC Direct Path INSERT Record Streaming over multiple protocols.
- 14. Copyright © 2022, Oracle and/or its affiliates From Sync to Reactive JDBC: Oracle R2DBC static String queryJdbc(java.sql.Connection connection) throws SQLException { try (java.sql.Statement statement = connection.createStatement()) { ResultSet resultSet = statement.executeQuery("SELECT * FROM CUSTOMERS"); 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 * FROM CUSTOMERS") .execute()) .flatMap(result -> result.map(row -> row.get(0, String.class))) .switchIfEmpty(Flux.error( new NoSuchElementException("Query returned zero rows"))); }
- 15. Copyright © 2022, Oracle and/or its affiliates Demo # 3: Oracle R2DBC ⚫ Oracle Reactive Relational Database Connectivity (R2DBC) ⚫ Oracle R2DBC Driver is a Java library that supports reactive Programming with Oracle Database ⚫ It implements the R2DBC Service Provider Interface (SPI) as specified by the Reactive Relational Database Connectivity (R2DBC) ⚫ The R2DBC SPI exposes Reactive Streams as an abstraction for Remote database operations ⚫ The sample code uses Project Reactor. It could use RxJava, Akka, or any RS library ⚫ Runs on Java 11+
- 16. Virtual Threads or Reactive? • Oracle JDBC supports both! • Want Virtual Threads? • Oracle JDBC has been “Virtual Thread Compatible” since 21.1.0.0 • Want Reactive? • Oracle R2DBC 1.0.0 is available now • Consume Flow interfaces directly from Oracle JDBC’s Reactive Extensions Copyright © 2022, Oracle and/or its affiliates
- 17. Virtual Threads or Reactive? • Benefits of Virtual Threads: • Easier to read and write • Easier to debug • Integration with JDK tools • Limitations of Virtual Threads: • Still a preview feature in JDK 19 • Some libraries are not compatible Copyright © 2022, Oracle and/or its affiliates Benefits of Reactive: • Available now. Supported on JDK 11 • Reactive Libraries (Reactor, RxJava, Akka, Vert.x) • Stream-like API with a functional style • Low-level concurrency is handled for you (locks, atomics, queues). Limitations of Reactive: • Steep learning curve • Harder to read and write • Harder to debug
- 18. Copyright © 2022, Oracle and/or its affiliates References • 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 • Introduction to Oracle JDBC 21c Driver Support for Virtual Threads - https://bit.ly/3UlNJWP • Reactive Streams Ingestion Library • Getting Started with the Java library for Reactive Streams Ingestion (RSI) - https://bit.ly/3rEiRnC • High-throughput stream processing with the Java Library for Reactive Streams Ingestion (RSI), Virtual Threads, and the Oracle ATP Database - https://bit.ly/3rATCTd • RSI - https://docs.oracle.com/en/database/oracle/ • R2DBC • Oracle R2DBC Driver – https://github.com/oracle/oracle-r2dbc • Develop Java applications with Oracle Database • JDBC – https://www.oracle.com/database/technologies/appdev/jdbc.html
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