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  1. Core Server
  2. SERVER-60638

Block $group stage from being pushed down to SBE when needsMerge is requested

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    • Icon: Improvement Improvement
    • Resolution: Fixed
    • Icon: Major - P3 Major - P3
    • 5.2.0
    • None
    • None
    • None
    • Fully Compatible
    • QE 2021-10-18

    Description

      The needsMerge behavior at mongod-side has not been yet implemented. Until it's implemented, we should block $group stage from being pushed down to SBE when needsMerge is requested from the mongos. Otherwise, it may lead to incorrect results for sharded $group, especially for accumulators that need special behavior for finalization steps when needsMerge is requested.

      This is just an interim fix until we implement needsMerge behavior, which is done by SERVER-59070.

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            yoonsoo.kim@mongodb.com Yoon Soo Kim
            yoonsoo.kim@mongodb.com Yoon Soo Kim
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