[jira] [Updated] (AMQ-5341) ActiveMQ documentation is inaccurate in describing Store-based Cursors for Fast Consumer

["Joe Luo (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/AMQ-5341?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Joe Luo updated AMQ-5341:
-------------------------
    Summary: ActiveMQ documentation is inaccurate in describing Store-based Cursors for Fast Consumer  (was: ActiveMQ documentation is inaccurate in describing Store-based Cursors for a Fast Consumer section)

> ActiveMQ documentation is inaccurate in describing Store-based Cursors for Fast Consumer
> ----------------------------------------------------------------------------------------
>
>                 Key: AMQ-5341
>                 URL: https://issues.apache.org/jira/browse/AMQ-5341
>             Project: ActiveMQ
>          Issue Type: Bug
>          Components: Documentation
>            Reporter: Joe Luo
>
> The ActiveMQ documentation: http://activemq.apache.org/message-cursors.html says
> {quote}
> As shown in Figure 6, store-based cursors address the fast consumer case by skipping the message cursor. When a message consumer is keeping pace with the message producers, persistent messages are written to the message store and moved directly into a dispatch queue for the consumer.
> {quote}
> Basically the statement is inaccurate since fast consumers are dealt with the same for both StoreCursor and VMCursor. It does not skip StoreCursor/Pending Cursor as the messages will be held in memory and dispatched from the memory. In fast consumers situation, StoreCursor will behave exactly the same as VMCursor but with a few differences that VMCursor will be a snapshot of entire persistent message store in memory as it needs to hold all messages in memory while StoreCursor will be a mapping of only a fraction of persistent message store in memory since it can only hold limited messages in memory.
> I'd suggest to replace the figure "Dispatching Messages for Fast Consumers" for StoreCursor (the first figure on the page) with the "VMCursor" one (The third figure on the page). And we should also replace original statement quoted above with something like below to point out the difference:
> {code}
> In fast consumers situation, StoreCursor will behave exactly the same as VMCursor but with a few differences that VMCursor will be a snapshot of entire persistent message store in memory as it needs to hold all messages in memory while StoreCursor will be a mapping of only a fraction of persistent message store in memory since it can only hold limited messages in memory.
> {code}



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