[jira] [Resolved] (AMQ-5266) Stuck Messages in Single Broker when using JDBC Persistent Store

["Gary Tully (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/AMQ-5266?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Gary Tully resolved AMQ-5266.
-----------------------------

    Resolution: Fixed

fix in http://git-wip-us.apache.org/repos/asf/activemq/commit/6348d119

scans are now limited to the last insert or the minimum pending insert, which ensures that we don't read ahead of the destination order.

> Stuck Messages in Single Broker when using JDBC Persistent Store
> ----------------------------------------------------------------
>
>                 Key: AMQ-5266
>                 URL: https://issues.apache.org/jira/browse/AMQ-5266
>             Project: ActiveMQ
>          Issue Type: Bug
>          Components: Message Store
>    Affects Versions: 5.10.0
>            Reporter: Gary Tully
>            Assignee: Gary Tully
>              Labels: Hanging, JDBC, Order
>             Fix For: 5.11.0
>
>
> With multiple concurrent producer transactions and active fast consumers it is possible to get out of order db insertions and scans resulting in a skipped dispatch. This scenario is exacerbated when the cursor cache is disabled because every dispatch will potentially result in a scan.
> the JDBC store maps jms transaction to jdbc connection transactions at the point of a commit and these can occur in parallel. The broker tracks a sequenceId to ensure ordering relative to a jms connection and  scans respect that order but there is currently nothing to stop a scan seeing a later sequence before an earlier sequence is stored. In other words, inserts can race, but the reader needs to limit a read to the lowest outstanding sequence.
> On a restart, any stuck messages will be replayed correctly, because the cursor transient state w.r.t to the last sequence id read will be reset.



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