Reactive Relational Database Connectivity 2020

Summarizes the state of R2DBC in 2020

Transcript

1. Reactive Relational Database
   Connectivity
   Mark Paluch • Spring Data Project Lead, R2DBC Contributor • @mp911de
   

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2. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
   Reactive Programming
   ● High-efficiency applications
   ● Fundamentally non-blocking
   ● No opinion on async
   ● Key differentiators: (pull-push) back pressure, flow control
   2
   

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3. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
   Subscriber
   Publisher
   Subscribe
   Data
   Demand
   

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4. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
   Subscriber
   Publisher
   Subscribe
   Data
   request(n)
   

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5. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
   WebFlux and WebClient
   5
   @GetMapping("/health")
   Mono compositeHealth() {
   return Mono.zip(
   webClient.get().uri("https://alpha-service/health")
   .retrieve().bodyToMono(Health.class),
   webClient.get().uri("https://bravo-service/health")
   .retrieve().bodyToMono(Health.class))
   .map(t -> composite(t.getT1(), t.getT2()));
   }
   

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6. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
   Roadblocks
   ● Barriers to using Reactive everywhere
   ● Data Access
   ● MongoDB, Apache Cassandra, Redis
   ● No Relational Database Access
   6
   

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7. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
   7
   A specification designed from the
   ground up for reactive programming
   https://r2dbc.io
   

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8. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
   Dependencies
   ● Reactive Streams
   ● Java 8
   8
   

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9. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
   Design Principles
   ● Embrace Reactive Types and Patterns
   ● Non-blocking, all the way to the database
   ● Documented specification
   ● Shrink the driver SPI
   ● Enable multiple "humane" APIs
   9
   

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10. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
    Driver SPI
    ● JDBC: same API for humane API and inhumane SPI for alternative clients
    like JPA, jOOQ, Jdbi, etc.
    ● API that users didn't like using and driver authors didn't like
    implementing
    ● Duplicating effort implementing the same "humane" affordances like ?
    binding
    10
    

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11. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
    Driver SPI: ConnectionFactory
    11
    Publisher create()
    ConnectionFactoryMetadata getMetadata()
    

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12. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
    Driver SPI: Connection
    12
    Publisher beginTransaction()
    Publisher close()
    Publisher commitTransaction()
    Batch createBatch()
    Publisher createSavepoint(String name)
    Statement createStatement(String sql)
    Publisher releaseSavepoint(String name)
    Publisher rollbackTransaction()
    Publisher rollbackTransactionToSavepoint(String name)
    Publisher setTransactionIsolationLevel(IsolationLevel isolationLevel)
    

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13. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
    Driver SPI: Statement
    13
    Statement add()
    Statement bind(String name, Object value)
    Statement bind(int index, Object value)
    Statement bindNull(String name, Class> type)
    Statement bindNull(int index, Class> type)
    Statement returnGeneratedValues(String… columnNames)
    Publisher execute()
    

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14. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
    Driver SPI: Result and Row
    14
    Publisher getRowsUpdated()
    Publisher map(BiFunction f)
    T get(String identifier, Class type);
    Object get(String identifier);
    T get(int index, Class type);
    Object get(int index);
    

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15. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
    Simple Select
    15
    Publisher values = connectionFactory.create()
    .flatMapMany(conn ->
    conn.createStatement("SELECT value FROM test")
    .execute()
    .flatMap(result ->
    result.map((row, metadata) -> row.get("value", 

    String.class))))
    

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16. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
    Transactional Update
    16
    Publisher results = connectionFactory.create()
    .flatMapMany(conn ->
    conn.beginTransaction()
    .thenMany(conn.createStatement("INSERT INTO test VALUES($1)")
    .bind("$1", 100).add()
    .bind("$1", 200).execute())
    .delayUntil(p -> conn.commitTransaction())
    .onErrorResume(t ->
    conn.rollbackTransaction().then(Mono.error(t))))
    

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17. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
    Great! But a Bit Verbose.
    ● Minimal set of implementation specific operations
    ● Definitely usable, but very verbose and prone to errors
    ● Explicit transaction management is analogous to try-catch-
    finally-try-catch in JDBC
    ● We need a "humane" client API. In fact we need many humane client
    APIs!
    17
    

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18. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
    R2DBC Client
    18
    Flux values = r2dbc.withHandle(handle ->
    handle.select("SELECT value FROM test")
    .mapRow(row -> row.get("value", String.class)))
    

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19. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
    Parametrized Statement
    19
    Flux updatedRows = r2dbc.withHandle(handle ->
    handle.createUpdate("INSERT INTO test VALUES($1, $2)")
    .bind("$1", 100).bind("$2", 200).add()
    .bind("$1", 300).bind("$2", 400).execute())
    

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20. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
    Transactional Update
    20
    Flux updatedRows = r2dbc.inTransaction(handle ->
    handle.createUpdate("INSERT INTO test VALUES($1, $2)")
    .bind("$1", 100).bind("$2", 200).add()
    .bind("$1", 300).bind("$2", 400).execute())
    

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21. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
    Spring Data R2DBC
    

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22. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
    Spring Data R2DBC
    22
    DatabaseClient client = DatabaseClient.create(connectionFactory);
    Flux rows = client
    .execute("SELECT * FROM person WHERE name = :name")
    .bind("name", "John Doe")
    .as(Person.class)
    .fetch()
    .all();
    

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23. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
    R2DBC Repositories
    23
    interface CustomerRepository extends
    ReactiveCrudRepository {
    @Query("SELECT * FROM … WHERE lastname = :lastname")
    Flux findByLastname(String lastname);
    }
    repository.findByLastname("Matthews")
    .doOnEach(c -> System.out.println(c.firstname))
    

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24. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
    Spring Data R2DBC
    ● Functional-reactive declaration of data access
    ● Fluent API
    ● Support for Transactions
    ● Named parameter support (Dialect-aware)
    ● Repositories
    ● Kotlin Coroutines extensions
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25. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
    Demo
    

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26. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
    Atomic Operations
    ● Application and Database transactions
    ● Classic implementations Thread-bound
    26
    

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27. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
    Reactive Transactions
    ● Application and Database transactions
    ● Pattern is still correct
    27
    

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28. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
    Reactive Transactions
    ● Application and Database transactions
    ● Pattern is still correct
    ● Bind transactional state to Subscription
    ● Reactor Context
    28
    

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29. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
    Reactive Transactions
    29
    PersonRepository people;
    AddressRepository addresses;
    @Transactional
    Mono savePerson(Person person, Address address) {
    return people.save(person)
    .then(addresses.save(address)).then();
    }
    

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30. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
    Programmatic Reactive Transactions
    30
    PersonRepository people;
    AddressRepository addresses;
    R2dbcTransactionManager txManager;
    TransactionalOperator rxtx = TransactionalOperator.create(txManager);
    Mono saved = people.save(person)
    .then(addresses.save(address))
    .as(rxtx::transactional).then();
    

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31. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
    Getting Started with R2DBC
    ● Available from Maven Central
    ● start.spring.io
    31
    

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32. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
    Getting Started with R2DBC
    32
    
    
    
    io.r2dbc
    r2dbc-bom
    Arabba-SR2
    pom
    import
    
    
    
    
    
    io.r2dbc
    r2dbc-h2
    
    
    

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33. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
    Getting Started with R2DBC
    33
    
    
    
    io.r2dbc
    r2dbc-bom
    Arabba-SR2
    pom
    import
    
    
    
    
    
    io.r2dbc
    r2dbc-h2
    
    
    

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34. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
    R2DBC Connection URL
    34
    r2dbc:pool:postgresql://localhost:5432/database?key=value
    ConnectionFactory connectionFactory =
    ConnectionFactories.get("r2dbc:postgresql://myhost/database?
    driver=foo");
    

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35. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
    Spring Boot Starter for R2DBC
    ● ConnectionFactory configuration
    ● R2DBC TransactionManager
    ● Embedded H2 support
    ● Actuator integration
    ● Schema.sql and Data.sql support
    ● @DataR2dbcTest
    35
    

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36. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
    36
    

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37. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
    R2DBC Ecosystem
    

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38. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
    R2DBC Ecosystem
    ● Specification document
    ● R2DBC SPI
    ● R2DBC Proxy
    ● Connection Pooling
    ● Client Implementations
    ● Spring Data R2DBC
    ● r2dbc-client
    ● Kotysa
    ● Drivers
    ● Google Cloud Spanner
    ● H2
    ● Microsoft SQL Server
    ● MySQL Driver (r2dbc-mysql,
    jasync-sql)
    ● MariaDB
    ● PostgreSQL
    ● SAP Hana
    38
    

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39. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
    Planned R2DBC Clients
    ● MyBatis (#1444)
    ● JDBI (#1454)
    ● jOOQ (#6298)
    ● Querydsl (#2468)
    ● Helidon (#581)
    ● Liquibase (CORE-3419)
    ● Flyway (#2502)
    ● Exposed (#456)
    ● Testcontainers (#1003)
    ● Go vote for a client you want to see happen.
    39
    

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40. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
    Planned R2DBC Drivers
    ● MariaDB (alpha-state by MariaDB Inc.)
    ● Firebird (Jaybird) investigating
    ● Oracle investigating
    ● DB2 foundation in the works (started with a vert.x driver first)
    ● Ask your vendor!
    40
    

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41. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
    Non-blocking SQL Database Endeavours
    ● Various individual driver projects (NDBC, Jasync, Vert.x, …)
    ● Hibernate Rx
    ● ADBA: Asynchronous Database API
    ● OJDBC 20 with Reactive Extensions
    ● Oracle looking into R2DBC
    41
    

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42. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
    Wrap up!
    

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43. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
    What Can You Do Today?
    ● End-to-end reactive non-blocking database communication
    ● Batching
    ● BLOB/CLOB
    ● Extensive Type Conversion
    ● Savepoints
    ● Transactions
    ● Leveraging Database-specific features
    ● ServiceLoader-based Driver discovery
    ● Connection URLs
    ● Categorized exceptions (Bad grammar, Data integrity violation, …)
    43
    

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44. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
    R2DBC Roadmap
    ● Started as experiment in early 2018
    ● Available as 0.8.0 SR2
    ● 0.9.0: Stored Procedures, Extended transaction spec, EventProvider
    44
    

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45. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
    Resources
    ● Website

    https://r2dbc.io
    ● Twitter

    @r2dbc
    ● GitHub

    https://github.com/r2dbc
    ● Mailing List

    https://groups.google.com/forum/
    #!forum/r2dbc
    ● Monthly Call

    1st Friday of Month 

    0630 PT/0930 ET/1530 CET
    45
    

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46. Thank you.
    r2dbc.io
    @mp911de
    

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