Amit Jain created OAK-2081:
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Summary: [Ordered Index] Incorrect index plan selection
Key: OAK-2081
URL: https://issues.apache.org/jira/browse/OAK-2081
Project: Jackrabbit Oak
Issue Type: Bug
Components: query
Reporter: Amit Jain
When an ordered index is defined on multiple properties the plan selection
seems to be incorrect. There are a few potential problems :
* For > or < conditions, the cost is doubled because of incorrect condition in
{{OrderedContentMirrorStoreStrategy#count}}. The condition should be {{cost >=
max}} instead of {{count > max}}
* If multiple properties are specified in the index definition, only the first
property is indexed and others ignored. IMO only the first should be used when
selecting the plan in {{OrderedPropertyIndexLookup#getIndexNode()}}, otherwise
it may happen that the property restriction that is not indexed is used for the
index plan.
* In {{QueryImpl#getBestSelectorExecutionPlan}} limit is used to damp the cost
which does not look right. E.g. limit is set to 10 and 2 plans with cost 190
and 110 are candidates, the plan ultimately selected out of the 2 after damping
with the limit will be arbitrary (the first to be processed) as the actual
estimated cost is effectively ignored.
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