[DERBY-4934] Provide automatic update and creation of index cardinality statistics (istat)

• Type: Task
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 10.8.1.2
• Fix Version/s: 10.8.1.2
• Component/s: SQL, Store
• Bug behavior facts: Performance
• Assignee: Kristian Waagan
• Reporter: Kristian Waagan
• Created: 07/Dec/10 21:02
• Updated: 26/May/11 09:52
• Resolved: 26/May/11 09:52

Description

Derby has been having problems with stale index cardinality statistics causing performance degradation because the optimizer picks a sub-optimal plan.
This master JIRA issue tracks the addition of a feature that will automatically update and create index cardinality statistics.

Note: For brevity I have decided to call the the feature istat during development

Issue Links

• incorporates: DERBY-5025 UpdateStatisticsTest fails after we enabled the automatic calculation of index statistics.
• is related to: DERBY-5132 Add tests to verify Derby behavior when automatic calculation of index statistics has been disabled
• is related to: DERBY-5086 Disable istat logging by default
• supercedes: DERBY-3788 Provide a zero-admin way of updating the statisitcs of an index
• supercedes: DERBY-4771 Continue investigation of automatic creation/update of index statistics

Sub-Tasks

• Add initial istat tests: Closed
• Add core istat daemon: Closed
• Enable explicit mode istat daemon code for UPDATE_STATISTICS: Closed
• Implement istat scheduling/triggering: Closed
• Enable istat daemon and tests: Closed