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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.

      Attachments

        Issue Links

          duplicates

          Bug - A problem which impairs or prevents the functions of the product. SERVER-57168 pipeline->clone() breaks on pipelines with union stage

          • Major - P3 - Major loss of function.
          • Closed
          is caused by

          Task - A task that needs to be done. SERVER-45538 Implement and test shard version retry logic for $unionWith sub-pipeline

          • Major - P3 - Major loss of function.
          • Closed
          is related to

          Bug - A problem which impairs or prevents the functions of the product. SERVER-57483 Results from $lookup stage are not cached for a resharding operation's sub-pipeline

          • Critical - P2 - Crashes, loss of data, severe memory leak.
          • Closed

          Task - A task that needs to be done. SERVER-30399 Add caching for $lookup non-correlated sub-pipeline prefix

          • Major - P3 - Major loss of function.
          • Closed
          related to

          Bug - A problem which impairs or prevents the functions of the product. SERVER-57705 DocumentSourceSequentialCache can wind up in a suboptimal location due to optimizations

          • Major - P3 - Major loss of function.
          • Backlog

          Bug - A problem which impairs or prevents the functions of the product. SERVER-57168 pipeline->clone() breaks on pipelines with union stage

          • Major - P3 - Major loss of function.
          • Closed

          Improvement - An improvement or enhancement to an existing feature or task. SERVER-57668 Cache chunk bounds as an array in resharding collection cloning pipeline

          • Major - P3 - Major loss of function.
          • Closed

          Activity

            People

              ted.tuckman@mongodb.com Ted Tuckman
              charlie.swanson@mongodb.com Charlie Swanson
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              Dates

                Created:
                Updated:
                Resolved: