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  1. Core Server
  2. SERVER-57483

Results from $lookup stage are not cached for a resharding operation's sub-pipeline

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Details

    • Fully Compatible
    • ALL
    • v5.0
    • Sharding 2021-06-14
    • 1

    Description

      DocumentSourceLookUp::buildPipeline() calls ShardServerProcessInterface::attachCursorSourceToPipeline() which calls sharded_agg_helpers::attachCursorToPipeline() and always serializes and re-parses, even when the pipeline may execute locally on the shard via ShardServerProcessInterface::attachCursorSourceToPipelineForLocalRead().

      Because the $sequentialCache stage omits itself from the serialized pipeline, the parsed pipeline which executes locally on the shard won't ever use the cache.

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          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-57168 pipeline->clone() breaks on pipelines with union stage

          • Major - P3 - Major loss of function.
          • 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

          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
          related to

          Bug - A problem which impairs or prevents the functions of the product. SERVER-57579 DocumentSourceSequentialCache doesn't clone, ruining non-correlated $lookup pipeline caching in sharded deployments

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

          Improvement - An improvement or enhancement to an existing feature or task. SERVER-57667 Improve processing speed for resharding's collection cloning pipeline

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

          Activity

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              max.hirschhorn@mongodb.com Max Hirschhorn
              max.hirschhorn@mongodb.com Max Hirschhorn
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              Dates

                Created:
                Updated:
                Resolved: