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Type:
New Feature
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Resolution: Unresolved
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Priority:
Minor - P4
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None
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Affects Version/s: None
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Component/s: Aggregation Framework
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Labels:None
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Query Optimization
Currently, there is no way to share a computed expression between different fields of a $project or $addFields other than using a previous $project or $addFields. This proposes adding a let bound to precompute shared expressions. Due to the current syntax of $project and $addFields it seems we will need new pipeline stage names (or perhaps name let and projection $let and $projection?).
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{$addFieldsShared:
{
let: {var1: expr1, var2: expr2, ...},
projection: {field1: expr3, field2: expr4, ...}
}
}
Where expr3 and expr4 can reference var1 and var2.