Details
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Task
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Status: Closed
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Major - P3
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Resolution: Done
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KANBAN BUCKET
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true
Description
Engineering Ticket Description:
I was looking at the optimizing aggregation pipelines docs page and didn't see this one listed.
This is only possible if the subsequent $match doesn't use any computed fields, but there could be a large win with regards to index usage if you could move the $match prior to a $project.
For example:
{ $project: { a: 1, b: 1, newField: { $add: ["$a", "$b"] } } },
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{ $match: { a : { $gt: 10 } }
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is the same as
{ $match: { a : { $gt: 10 } },
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{ $project: { a: 1, b: 1, newField: { $add: ["$a", "$b"] } } }
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because the $match is only using fields that exist in the original document.
Attachments
Issue Links
- documents
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SERVER-19153 Conditionally push $match before $project
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- Closed
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- is related to
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DOCS-10960 Update Aggregation Pipeline Optimization
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- Closed
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- related to
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- Closed
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