[jira] [Created] (AMQ-6782) Document about cursorMemoryHighWaterMark is misleading

["Alvin Lin (JIRA)" <ji...@apache.org>]

Alvin Lin created AMQ-6782:
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             Summary: Document about cursorMemoryHighWaterMark is misleading
                 Key: AMQ-6782
                 URL: https://issues.apache.org/jira/browse/AMQ-6782
             Project: ActiveMQ
          Issue Type: Bug
          Components: Documentation
    Affects Versions: 5.15.0
            Reporter: Alvin Lin


In http://activemq.apache.org/per-destination-policies.html the description for "cursorMemoryHighWaterMark" is kind of misleading; the description about that the threshold will apply to "the destination's memoryLimit (when defined) " made me think that it applies to TopicSubscription as well. 

I thought if I configure a topic with memoryLimit of 100MB and system memory limit of 1GB, then TopicSubscription (or more specifically the FilePendingMessageCurosr) uses cursorMemoryHighWaterMark against 100MB. But through testing, code reading, and http://blog.christianposta.com/activemq/activemq-understanding-memory-usage I found out the hard way this is not the case; only queues will use cursorMemoryHighWaterMark against the per destination memory limit. 

My suggestion is to add additional notes that the configured cursorMemoryHighWaterMark applies only to system memory in the case of topic.



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