Gary Tully created AMQ-5266:
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Summary: 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
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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