Details
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Improvement
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Status: Closed
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Major - P3
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Resolution: Duplicate
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2.6.1
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None
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None
Description
Prior to 2.6, the query planner would consider plans for $or beneath an $and according to a logical rewrite to disjunctive normal form. For example, suppose we have indices {a: 1, b: 1} and {a: 1, c: 1}. For the query
db.coll.find({a: 3, $or: [{b: 4}, {c: 5}]});
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the query planner would instead plan this as
db.coll.find({$or: [{a: 3, b: 4}, {a: 3, c: 5}]});
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The first clause uses the index {a: 1, b: 1} and the second uses {a: 1, c: 1}.
In 2.6, the query planner does not consider this rewrite and therefore can miss some of the plans considered by 2.4.
Attachments
Issue Links
- duplicates
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SERVER-13732 Predicates in top-level implicit AND query not considered when generating index access plan for contained OR
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- Closed
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- is duplicated by
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- Closed
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