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    Type:Improvement 
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    Resolution: Unresolved
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    Priority:Major - P3 
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    Affects Version/s: None
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    Component/s: None
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        Query Optimization
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After discussion we decided not to do this as part of SERVER-45620 because it isn't clear which values should supersede others.
- related to
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                    SERVER-45620 Have $union introspect the sub-pipeline to allow for more liberal constraints if the sub-pipeline is not constrained -         
- Closed
 
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