[SERVER-63449] Improve the decision logic for choosing HJ when lowering $lookup into SBE Created: 08/Feb/22  Updated: 29/Oct/23  Resolved: 08/Mar/22

Status: Closed
Project: Core Server
Component/s: None
Affects Version/s: None
Fix Version/s: 6.0.0-rc0

Type: Task Priority: Major - P3
Reporter: Irina Yatsenko (Inactive) Assignee: Yoon Soo Kim
Resolution: Fixed Votes: 0
Labels: None
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified

Backwards Compatibility: Fully Compatible
Sprint: QE 2022-03-07, QE 2022-03-21
Participants:

 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.



 Comments   
Comment by Githook User [ 08/Mar/22 ]

Author:

{'name': 'Yoonsoo Kim', 'email': 'yoonsoo.kim@mongodb.com', 'username': 'yun-soo'}

Message: SERVER-63449 Add HashJoin query knobs
Branch: master
https://github.com/mongodb/mongo/commit/210df2e4169b4ff9ae074da943771b31228c0c48

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