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  1. Core Server
  2. SERVER-57579

DocumentSourceSequentialCache doesn't clone, ruining non-correlated $lookup pipeline caching in sharded deployments

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Details

    • Bug
    • Status: Closed
    • Major - P3
    • Resolution: Duplicate
    • 4.4.0, 5.0.0-rc0
    • None
    • None
    • None
    • ALL
    • Query Optimization 2021-06-28

    Description

      As outlined in SERVER-57483, the serialization code isn't appropriate as a mechanism to clone this stage. We should investigate a more robust way to distinguish the two use cases of serializing to the shards and serializing for being copied.

      The impact of this problem is quite large. It means that your performance of a non-correlated $lookup might degrade when you move from a replica set to a sharded cluster.

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              ted.tuckman@mongodb.com Ted Tuckman
              charlie.swanson@mongodb.com Charlie Swanson
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                Created:
                Updated:
                Resolved: