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    Type:Improvement 
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    Resolution: Done
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    Priority:Major - P3 
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    Affects Version/s: None
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    Component/s: Index Maintenance, Querying
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Update:
Index intersection is on by default. The query planner currently limits itself to 2 indices at a time, though this limit may increase in the future.
Original Text:
This should support both single and multiple index intersections.
This should support queries that which want to use a covered index; then complex intersections would never need to hit the document to return the values.
A more detailed description of index intersection in a traditional RDMS can be found here:
http://www.sql-server-performance.com/2003/index-intersection/
- depends on
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                    SERVER-3414 consider using nscannedObjects in addition to nscanned when selecting a query plan -         
- Closed
 
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- is depended on by
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                    SERVER-4572 Geospatial index cannot be used in $and criteria of a query? -         
- Closed
 
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- is duplicated by
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                    SERVER-7742 Improve the way indexes are used to do a range query on one field and sort on another -         
- Closed
 
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                    SERVER-8753 Query optimizer doesn't use hashed key in a query with sorting on a different indexed value -         
- Closed
 
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                    SERVER-3118 get best intersection match via query -         
- Closed
 
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                    SERVER-8768 implement support for interleaving btree and non btree cursors in query optimizer cursor selection code -         
- Closed
 
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                    SERVER-8140 Compound Index with 2d and Text -         
- Closed
 
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- related to
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                    SERVER-1000 $all with query optimizer -         
- Closed
 
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                    SERVER-9148 In text searches with $near filter, results don't obey filter -         
- Closed
 
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                    SERVER-8790 Introduce composable "stages" in query execution -         
- Closed
 
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