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  1. Core Server
  2. SERVER-63449

Improve the decision logic for choosing HJ when lowering $lookup into SBE

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    • Icon: Task Task
    • Resolution: Fixed
    • Icon: Major - P3 Major - P3
    • 6.0.0-rc0
    • None
    • None
    • None
    • Fully Compatible
    • QE 2022-03-07, QE 2022-03-21

    Description

      1. Add a query knob for kMaxHashJoinCollectionSize. Currently, we've hardcoded the value of 100*1024*1024 in the code that selects the physical join algorithm. This should be a configurable knob (both for testing purposes and to let customers to, effectively, fully suppress HJ)
      2. Add a query knob that limits the number of records in the foreign collection to be considered for a HJ.
      3. Check the storage size of the collection.

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            yoonsoo.kim@mongodb.com Yoon Soo Kim
            irina.yatsenko@mongodb.com Irina Yatsenko (Inactive)
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              Updated:
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