[SERVER-82491] Avoid needless floating point calcuations in SBE std dev accumulator Created: 27/Oct/23  Updated: 30/Oct/23  Resolved: 30/Oct/23

Status: Closed
Project: Core Server
Component/s: None
Affects Version/s: None
Fix Version/s: 7.2.0-rc0

Type: Improvement Priority: Major - P3
Reporter: Ivan Fefer Assignee: Ivan Fefer
Resolution: Fixed Votes: 0
Labels: None
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified

Issue Links:
Depends
Backwards Compatibility: Fully Compatible
Sprint: QE 2023-10-30, QE 2023-11-13
Participants:
Linked BF Score: 145

 Description   

While merging std dev accumulators in SBE, we should not calculate new m2 and mean values if one of the merged accumulator values has zero data.

  



 Comments   
Comment by Githook User [ 30/Oct/23 ]

Author:

{'name': 'Ivan Fefer', 'email': 'ivan.fefer@mongodb.com', 'username': 'Fefer-Ivan'}

Message: SERVER-82491 In std dev accumulator short-circuit merging if oldCount is zero
Branch: master
https://github.com/mongodb/mongo/commit/92b41dc3f1dbcb7b3f8c38a4d9052f2c58cc03a2

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