[jira] [Created] (NIFI-7563) Optimize the usage of JMS sessions

["Gardella Juan Pablo (Jira)" <ji...@apache.org>]

Gardella Juan Pablo created NIFI-7563:
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             Summary: Optimize the usage of JMS sessions
                 Key: NIFI-7563
                 URL: https://issues.apache.org/jira/browse/NIFI-7563
             Project: Apache NiFi
          Issue Type: Improvement
          Components: Extensions
    Affects Versions: 1.11.4, 1.9.2, 1.10.0, 1.7.1, 1.8.0, 1.6.0
            Reporter: Gardella Juan Pablo
            Assignee: Gardella Juan Pablo


[MessageProducer|https://docs.oracle.com/javaee/7/api/javax/jms/MessageProducer.html] objects are created by [Session|https://docs.oracle.com/javaee/7/api/javax/jms/Session.html].

Below an scenario to reproduce the problem. Suppose it is required to publish 1 message to the destination {{D}} using [PublishJMS|http://nifi.apache.org/docs/nifi-docs/components/org.apache.nifi/nifi-jms-processors-nar/1.11.4/org.apache.nifi.jms.processors.PublishJMS/index.html]. The message is a flow file in the processor input queue.

It is important to know that internally the processor is using [CachingConnectionFactory|https://github.com/spring-projects/spring-framework/blob/master/spring-jms/src/main/java/org/springframework/jms/connection/CachingConnectionFactory.java] to reuse objects and a [worker|https://github.com/apache/nifi/blob/a1b245e051245bb6c65e7b5ffc6ee982669b7ab7/nifi-nar-bundles/nifi-jms-bundle/nifi-jms-processors/src/main/java/org/apache/nifi/jms/processors/AbstractJMSProcessor.java#L180] to be able to use in thread safe manner. For JMS publishers, the default configuration is to cache connections, sessions (only 1) and message producers.

*Preconditions*
 # Flowfile has either {{jms_destination}} or {{jms_replyTo}} attribute defined. Due to NIFI-7561, it should contain the word {{queue}} or {{topic}}.
 # For simplicity, the processor is the first time it processes messages.

*Scenario*
 # Processor picks the message. The [worker|https://github.com/apache/nifi/blob/a1b245e051245bb6c65e7b5ffc6ee982669b7ab7/nifi-nar-bundles/nifi-jms-bundle/nifi-jms-processors/src/main/java/org/apache/nifi/jms/processors/AbstractJMSProcessor.java#L180] is created.
 # Connection {{C1}} and session {{S1}} are created. The [Message|https://docs.oracle.com/javaee/7/api/javax/jms/Message.html] {{M1_S1}} is created and [MessageProducer|https://docs.oracle.com/javaee/7/api/javax/jms/MessageProducer.html] {{MP_S1}} created too. Required to deliver first message at [JMSPublisher#publish|https://github.com/apache/nifi/blob/master/nifi-nar-bundles/nifi-jms-bundle/nifi-jms-processors/src/main/java/org/apache/nifi/jms/processors/JMSPublisher.java#L65].
 # S1 and C1 are stored in {{CachingConnectionFactory}}. The caching connection factory is created at [AbstractJMSProcessor.java#L208|https://github.com/apache/nifi/blob/master/nifi-nar-bundles/nifi-jms-bundle/nifi-jms-processors/src/main/java/org/apache/nifi/jms/processors/AbstractJMSProcessor.java#L208].
 # An attempt to create a new connection and a new session are requested to the connection factory to create destination defined in the header {{jms_destination}} at [JMSPublisher.java#L131|https://github.com/apache/nifi/blob/master/nifi-nar-bundles/nifi-jms-bundle/nifi-jms-processors/src/main/java/org/apache/nifi/jms/processors/JMSPublisher.java#L131]. Notice the connection {{C1}} is reused although *{{S1}} is not reused* (it is required to check internal logic in CachingConnectionFactory to understand why not). A new session {{S2}} is created and stored in the {{CachingConnectionFactory}} as the new cached session.
 # Message is published and {{S1}} and {{MP_S1}} are closed. As {{S1}} is not in the cache, it is physically closed and {{MP_S1}}.
 # At this point of time, the cached objects are {{C1}}, {{S2}}. *Ideally*, all resources should be reused.

The scenario if it is applied to N consecutive messages create a lot of sessions and message producers. We found this issue by adding an [Interceptor|https://activemq.apache.org/interceptors] to detect the optimal usage of resources. For example, only one message producer per connection. In below scenario we will be created N producers for the same connection. 




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