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Type: Improvement
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Resolution: Duplicate
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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
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(copied to CRM)
The $graphLookup aggregation stage allows for graph searches across unsharded collections or to use results from a sharded collection to perform a graph search in an unsharded collection. It does not allow for the "from" collection to be sharded.
We understand this is a painful and unfortunate limit on the capabilities of the query language. We strive to make it so that the distribution of data does not impact the experience with the database, but are unable to implement this improvement to our satisfaction at this time. Implementing this feature would be subject to the same problems as SERVER-29159, where you can find a summary of the reasons we haven't implemented it. SERVER-29159 also describes some workarounds which may be applicable to your use case as well.
We plan to work towards this feature in the future, but have no specific target date or release at this time.
Original Description
In the docs it mentions that the from field in $graphLookup stage in the aggregation pipeline cannot take a sharded collection.
Wanted to know if this would be allowed in the near future. Would be a great addition.
- depends on
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SERVER-38728 Allow pipeline with $lookup into a sharded collection to run on mongod
- Closed
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SERVER-32666 Allow $graphLookup against a sharded collection to execute on mongos
- Closed
- related to
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SERVER-29159 Allow "from" collection of $lookup to be sharded
- Closed