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Type: New Feature
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Resolution: Done
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Priority: Major - P3
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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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None
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Query Optimization
postgres supports a windowing capability that allows for calculations within a window of visible data; this is for streaming data.
It's easy to imagine supporting something like a $window pipeline operator, which specifies how many documents to include in the window. Within, aggregate expressions can reference documents within the window using some kind of indexing. This can be used to calculate things like moving averages, e.g., have a window of 5 items, and create a computed field that is (doc[0] + doc[-1] + doc[-2] + doc[-3] + doc[-4])/5, or something like that.
- depends on
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SERVER-52328 Enable feature flag for Window Functions
- Closed
- is related to
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SERVER-447 new aggregation framework
- Closed
- related to
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SERVER-29161 Ability to access previous document in $group aggregation
- Closed
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SERVER-29339 allow using $reduce expression as accumulator in $group
- Backlog