[AMQ-5266] Stuck Messages in Single Broker when using JDBC Persistent Store

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 5.10.0
• Fix Version/s: 5.11.0
• Component/s: Message Store
• Labels: Hanging JDBC Order
• Assignee: Gary Tully
• Reporter: Gary Tully
• Created: 09/Jul/14 16:03
• Updated: 09/Feb/16 12:54
• Resolved: 10/Jul/14 12:17

Description

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.

Issue Links

• relates to: AMQ-6164 queue sendLock prevents concurrent journal updates