[AMQ-3196] Speed up initial message delivery for offline durable sub with keepDurableSubsActive=true and JDBC store

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 5.4.2
• Fix Version/s: 5.5.0
• Component/s: Message Store
• Labels: DurableSubscriptions JDBC Offline Performance
• Assignee: Gary Tully
• Reporter: Gary Tully
• Created: 02/Mar/11 16:16
• Updated: 02/Mar/11 16:25
• Resolved: 02/Mar/11 16:25

Description

Follow on from https://issues.apache.org/jira/browse/AMQ-3188
Durablesubs are kept active by default, but their cursors are stopped requiring a read of the store to determine the message backlog. With a large prioritised backlog and th JDBC store, getting the store size can be costly as it requires a full table scan.
Currently there are three calls to getStoreSize, there should be only one when the sub is initially created.
The implication is that on reactivation of an offline durable sub, there is a delay of an additional potentially slow jdbc call before dispatch resumes.

Issue Links

• relates to: AMQ-3188 Full table scan for durable subs in jdbc store when priority enabled; very slow with large message backlog