Under the Hood of Reactive Data Access Mark Paluch @mp911de 1

Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Spring Data Modules 2 JPA

Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Reactive Spring Data Modules 3 JPA

Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ JDBC Fully-blocking API Non-blocking API announced (JDK-8188051) 4 http://mail.openjdk.java.net/pipermail/jdbc-spec-discuss/ • JDK-8188051: http://hg.openjdk.java.net/jdk10/sandbox/jdk/rev/a31057bda7c5

Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Relational Databases Limited scalability Resource synchronization Transactions 5

Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Query by time 6 Transport

Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Synchronous Data Access 7 Data store App Data store App Data store

Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Reactive Data Access 8 Data store App Data store Data store Data store App

Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Differences to imperative Data Access Drivers require threading infrastructure Timeout handling different 9

Reactive NoSql drivers

Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Reactive drivers End-to-end nonblocking Asynchronous request-response processing Non-blocking pooling Non-blocking connect 11

Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Application Driver Application 12 Request Server selection Queueing Write Response decoding Response buffering Request completion Response

Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ MongoDB Reactive-over-async driver Cursor lifecycle Pluggable I/O Pooled connections 13

Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Query by time 14 Request Response (chunk) Response (complete) Prefetch (cont.d) Query Emit elements Result processing

Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ MongoDB Driver Fetching 15 Operator MongoDB Subscriber request(Long.MAX_VALUE) request(Long.MAX_VALUE)

Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ MongoDB Driver Fetching 16 Filter MongoDB Subscriber request(Long.MAX_VALUE) request(Long.MAX_VALUE)

Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ MongoDB Driver Fetching 17 Operator (filter) MongoDB Subscriber request(1) Dropped element request(Long.MAX_VALUE)

Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Specific Features Tailable Cursors (@Tailable) MongoDB 3.6: Change Streams 18 Cursor size derived from demand

Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Redis Reactive driver (Lettuce 5) Based on Netty and Project Reactor Singleton connection Pooled connections 19

Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Command by time 20 Request Command Command (subscription) Response (chunk) Response (complete)

Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Specifics Use ByteBuffer instead byte[] @null handling: Emission of empty buffers Suspend reading if no demand 21

Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Apache Cassandra Reactive bridge over async driver Netty-based driver (Datastax) Pooled connections 22

Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Query by time 23 Request Response (chunk) Response (complete) Query Emit elements Result processing Next page

Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Outlook Cassandra driver 4.0 in the works Likely support for reactive execution model Emit items as they are received 24 https://github.com/datastax/java-driver/tree/4.x • https://datastax-oss.atlassian.net/browse/JAVA-1505

Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Couchbase Reactive driver driver Based on Netty and RxJava 1 Multiple connection schemes 25

Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Couchbase Fetching Key-Value, DCP 1. Request 2. Response 3. Emit results
 Search, Query, View 1. Request 2. Response streaming 26

Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Command by time 27 Request Command Command (subscription) Response (chunk) Response (complete)

Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Outlook Couchbase driver likely to move to RxJava 2 • No tickets/decisions yet 28

Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Resources Slides – mp911.de/s1p-hood-slides Example Code – mp911.de/s1p-hood-code Spring Data Examples – Repository @ Github Find us on Gitter! 29

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