Jms deep dive [con4864]
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JavaOne 2016 JMS is pretty simple, right? Once you’ve mastered topics and queues, the rest can appear trivial, but that isn’t the case. The queuing system, whether ActiveMQ, OpenMQ, or WebLogic JMS, provides many more features and settings than appear in the Java EE documentation. This session looks at some of the important extended features and configuration settings. What would you need to optimize if your messages are large or you need to minimize prefetching? What is the best way to implement time-delayed messages? The presentation also looks at dangerous bugs that can be introduced via simple misconfigurations with pooled beans. The JMS APIs are deceptively simple, but getting an implementation into production and tuned correctly can be a bit trickier.
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Jms deep dive [con4864]
- 1. JMS DEEP DIVE Ryan Cuprak
- 2. About Me Ryan Cuprak • @ctjava • rcuprak@gmail.com • http://www.cuprak.info • https://www.linkedin.com/in/rcuprak Updated For • EE 7 • EJB 3.2
- 4. JMS Background • Specification Revisions • JMS 1.0.2b – June 26, 2001 • JMS 1.1 – April 12, 2002 • JMS 2.0 – May 21, 2013 • JMS 2.1 – Vote to Continue! • Mandatory in Java EE 1.4 (November 11, 2003)! • MOM pre-dates JMS & Java EE
- 6. #1 Upgrade Code to EE 7 Major changes in Java EE 7 (JMS 2.0) Introduced in Java EE 7: • JMSContext – replaces Connection and Session • JMSProducer – replaces MessageProducer • JMSConsumer – replaces MessageConsumer Best Practice
- 7. #1 Upgrade Code to EE 7… Best Practice
- 8. #1 Upgrade Code to EE 7… Best Practice
- 9. #2 ActiveMQ & Java EE 7 Gotcha
- 10. #2 Java EE 7: Stumper… What??? Gotcha
- 11. #2 Java EE 7: Stumper… http://tinyurl.com/h7cvl8b ActiveMQ supports JMS 1.1 – not JMS 2! Gotcha
- 12. #3 Exception Handling What is the impact of a RuntimeException? Bad! Best Practice
- 13. #3 Exception Handling… Runtime Exception: • Rollback and re-delivery of message • Destruction of MDB and possibly connection Best Practice
- 14. #4 Which of these are optional? 1. JMSMessageID 2. Overriding Message Header Fields 3. JMS Defined Properties 4. Provider Specific Properties 5. Distributed Transactions 6. Multiple Sessions All of them! Best Practice
- 15. #5 Pre-fetching • Message consumer (RAR) pre-fetches a set of messages to distribute to consumers (MDBs). • Poorly configured pre-fetch • Starve other consumers • Heap exhaustion • Default ActiveMQ: 1000 messages! Gotcha
- 17. #5 Large Messages What happens to a container when you send gigantic messages with large pre-fetch? Best Practice
- 18. #6 XATransactions How do you ensure that a messages is committed only if the database commits? Best Practice
- 19. #6 XATransactions XA Data Source Best Practice
- 20. #7 Wire Protocols What are the different wire protocols and what are their unique features? • Openwire • Cross language wire protocol for messaging • Native protocol for ActiveMQ • AMQP – Advanced Message Queuing Protocol • ISO 19464 – binary wire protocol with widespread adoption • Designed for high performance interoperable messaging • MQTT – Message Queue Telemetry Transport • Simple binary protocol – good for embedded/mobile • Stomp – Simple/Streaming Text Oriented Messaging Protocol • Text based protocol with simple semantics Are you using the right wire protocol? Best Practice
- 21. #7 Wire Protocols & MOM MOM OpenWire AMQP MQTT Stomp Other OpenMQ X X ActiveMQ X X X X RabbitMQ X X X HornetQ X X WebLogic X WebSphere MQ X X • MQTT – IoT/embedded/mobile • Stomp – WebSockets – not high volume Best Practice
- 22. #8 Dead Letter Queue What is the dead letter queue and why should I care? • Message that is repeatedly refused by a client. • JMS provider will retry multiple times. • Messages ultimately moved to Dead Letter Queue (DLQ) Order Queue Update Queue Update Queue Update Queue Best Practice
- 23. #8 Dead Letter Queue… • Hundreds of messages • How to recover? Best Practice
- 24. #8 Dead Letter Queue… ActiveMQ DLQ configuration – DLQ per queue. Best Practice
- 25. #9 Expiring Messages What’s wrong with the following code? 1. Message.setJMXExpiration() is for use by the container. 2. Ignored if you set it. Gotcha
- 26. #9 Expired Messages & DLQ • Expired messages dumped to DLQ • Messages build-up over time! Best Practice
- 27. #9 Expired Messages & DLQ… ActiveMQ solution HornetQ HornetQ messages are lost unless configured. Best Practice
- 28. #10 MDB Pools Do I need to configure MDB pools? Best Practice
- 29. #10 MDP Pools… • Don’t accept default MDB pool sizes. • Monitor and adjust MDB pool sizes based on load. glassfish-ejb-jar.xml Best Practice
- 30. #11 Types of JMS Messages What are the different types of messages types? StreamMessage Serialized stream of objects. MapMessage Message composed of name/value pairs. Names must be unique. TextMessage Simple message for Strings. ObjectMessage Message consisting of a serialized Java Object. BytesMessage Raw stream of bytes. WebLogic includes XMLMessage: • Optimized for XML. • Supports filtering on XML content. Best Practice
- 31. #12 Troubleshooting What’s this message? ? Best Practice
- 32. #12 Troubleshooting Set descriptive headers on the messages! Best Practice
- 33. #13 Web Socket and JMS Java EE 7 Server Web Socket Endpoint JMS Provider JMS Provider Stomp over Web Sockets Best Practice
- 34. #13 Web Socket and JMS… • Stomp protocol is a simple text-oriented messaging protocol. • Messaging server must support WebSockets • Initial handshake is HTTP • Message providers supporting STOMP & WebSockets: • ActiveMQ • RabitMQ • WebLogic • Enable for ActiveMQ: <transportConnector name="ws" uri="ws://0.0.0.0:61614"/> Best Practice
- 35. #14 Delayed Message Delivery Can I send a message but have it delayed? Extended feature in ActiveMQ. • Send delay (AMQ_SCHEDULED_DELAY) • Re-send delay (AMQ_SCHEDULED_PERIOD) • Repeat count (AMQ_SCHEDULED_REPEAT) Best Practice
- 36. #15 Priority & Messages What does message priority mean? • Message priority scale: 0-9 (0: lowest 9: highest) • Default message priority: 4 • JMS specification does not require a provider strictly implement message ordering. • Not dependable! Best Practice
- 37. #15 Priority & Messages Enforcing priority: • Apache Camel with Resequencer • http://camel.apache.org/resequencer.html • Use Selectors: • JMSPriority > 6 • JMSPriority < 6 Best Practice
- 38. #16 Protocol Framing So I need a bigger message frame? 104 MB Best Practice
- 39. #16 Protocol Framing Client exception: Server Exception WARN | Transport Connection to: tcp://127.0.0.1:54025 failed: java.io.IOException: Frame size of 404 bytes larger Best Practice
- 40. #17 Leaks & Variable Loads Load testing always at 100%? Scenario: • Message Driven Bean with a connection to a remote resource. • Standing pool size: 3 Gotcha
- 41. #17 Leaks & Variable Loads… Oops, resource only leak as bean instances fluctuate! 0 5 10 15 20 25 30 35 1 2 3 4 5 6 7 8 9 Leak Bean Gotcha
- 42. #18 Advisory Messages Extended ActiveMQ feature: • Consumers, producers and connections starting and stopping • Temporary destinations being created and destroyed • messages expiring on topics and queues • Brokers sending messages to destinations with no consumers. • Connections starting and stopping Best Practice
- 43. #18 Advisory Messages… Best Practice
- 44. #20 Know your Activation Spec Properties Property Required Default Description acknowledgeMode Auto-acknowledge Auto-acknowledge or Dups-ok- acknowledge clientId Set n RA Required for durable destinationType X null Queue or Topic Destination X null Destination name enableBatch false Transaction batching maxMessagesPerBatch 10 Message per transaction batch maxMessagesPerSessions 10 Pre-fetch size maxSessions 10 Max concurrent sessions messageSelector null Selector noLocal false Include local msg? ActiveMQ Best Practice
- 45. #20 Know your Activation Spec Properties Property Default Description password Set inRA Password for JMS connection subscriptionDurability NonDurable NonDurable or Durable subscriptionName null Name of subscription userName Set in RA Username for JMS connection useRAManagedTransaction false initialRedeliveryDelay 1000 Re-delivery delay maximumRedeliveries 5 Max re-deliveries redeliveryBackOffMultiplier 5 Multiplier for back-off. redeliveryUseExponentialBackOff false Configures exponential back-off. ActiveMQ Best Practice
- 46. #20 Know your Activation Spec Properties • ActiveMQ – only 2 properties were required • Key tuning questions: • Individual messages take a long time to process? • Many messages or few messages? • Batch processing of messages? • Ok to process duplicates? Best Practice
- 47. #21 Configuration Conflicts Default for configuration for an MDB and ActiveMQ RA: • Max MDB Pool Size (default 25) • Max Sessions (default 10) • MaxMessagesPerSessions (default 10) How many messages can we process concurrently? 10 Best Practice
- 48. #22 Configure Message Persistence • JMS message providers message persistence is often configurable and tunable • Concerns: • Available file/descriptors and disk space • I/O throughput • Flush frequencies • ActiveMQ • KahaDB – file-based transaction data store (journaled) • AMQ message store – file based store, file per destination, index must be rebuilt for non-planned termination • JDBC message store Best Practice
- 49. #22 Configure Message Persistence… API does exist for ActiveMQ KahaDB! Best Practice
- 50. #23 Deadlocked Consumer Consumer blocks! • Pre-fetched messages are stuck in limbo • App cannot be un-deployed • App container may not shutdown properlyGotcha
- 51. #24 Multiple Destinations • ActiveMQ supports sending messages to multiple queues and topics. • Targets should be a comma separated list. • Use prefix topic:// or queue:// Extended Feature
- 52. #25 Multiple Destination Consumption • ActiveMQ supports consuming messages from multiple destinations – both queues and topics • Destination naming: • ‘.’ separates elements in a destination name • ‘*’ matches one element • ‘>’ matches one or all trailing elements • Example topics: • us.ca.sfo.takeoffs • us.ca.sfo.landings • us.ca.lax.takeoffs • us.ct.bdl.takeoffs • Patterns: • *.*.*.takeoffs – receive all takeoff messages • us.ca.> - all landings and takeoffs in CA Extended Feature
- 53. #25 Multiple Destination Consumption… Extended Feature
- 54. #26 GlassFish 4 Bug Containers can have bugs! • GlassFish 3.x no message delay with MDBs and ActiveMQ. • GlassFish 4.1.1 2 minute delay with messages from ActiveMQ but NOT OpenMQ Gotcha
- 55. #26 GlassFish 4 Bug… Timeout increased to 2 minutes! Gotcha
- 56. #26 GlassFish 4 Bug… Code path was different for OpenMQ. Gotcha
- 58. #27 Transactions… To ensure item is saved: Best Practice
- 59. #28 Concurrency Following objects support concurrent access: • ConnectionFactory • Connection • Destination Following object DO NOT support concurrent access: • Session • MessageProducer • MessageConsumer Best Practice
- 60. #29 JMSX Properties Property Matched Modified Description JMSXUserID X X Id of user sending message JMSXAppID X X App sending message JMSXProducerTXID Producer transaction id JMSXConsumerTXID Transaction ID consumer JMSXRcvTimestamp Time delivered to consumer JMSXDeliveryCount X Delivery attempts JMSXState Provider specific state JMSXGroupID X X Message group id JMSXGroupSeq X X Sequence number in group No all properties are supported by all providers! Best Practice
- 61. #30 Message Groups • Message Groups: • Guaranteed ordering of the processing of related messages across a single queue • Load balancing across multiple consumers. • High availability / auto-failover • Usage: • message.setStringProperty("JMSXGroupID", ”JavaOne"); • message.setIntProperty("JMSXGroupSeq”,1); • message.setIntProperty("JMSXGroupSeq”,-1); // closes group • ActiveMQ enhancement: • JMSXGroupFirstForConsumer Best Practice
- 62. #31 Message Selectors • Message selectors used to filter messages. • Selectors use subset of SQL92 • Selectors cannot reference payload, only header properties Literals TRUE/FALSE, numbers, scientific notation Identifiers Header or property field. Operators AND, OR, LIKE, BETWEEN, =, <>, <, >, <=, =>, +, -, *, /, IS NULL, IS NOT NULL Best Practice
- 63. Best Practices • High availability (HA) for production • Protect queues/topics with passwords • Enable and configure SSL • Configure provider data store • Backup provider data store • Configure DQL policy • Monitor DLQ • Add descriptive message headers • Pick and tune messaging transport • Use Apache Camel and integration patterns
- 65. JMS 2.1 Vote for JMS 2.1! • Flexible MDBs (EE) • CDI beans as Listeners • Batch Delivery • Acknowledgment Modes • setMessageListener (EE) • create Connection factory (SE) • create Queue/Topic (SE) • Repeatable Annotations • Redelivery configuration (EE)
- 66. Q&A
Notas do Editor
- I am Ryan, this is Michael,
- We write some wonderful code that uses the Java E