[SERVER-77510] Reduce Bonsai sampling variability in perf variants Created: 26/May/23  Updated: 29/Oct/23  Resolved: 23/Jun/23

Status: Closed
Project: Core Server
Component/s: None
Affects Version/s: None
Fix Version/s: 7.1.0-rc0

Type: Task Priority: Major - P3
Reporter: Alya Berciu Assignee: Alya Berciu
Resolution: Fixed Votes: 0
Labels: M1
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified

Attachments: PNG File Heuristic, Micro, ops_per_sec.png     PNG File Sampling, Micro, ops_per_sec noisy.png     PNG File Screenshot 2023-06-21 at 15.17.49.png     PNG File Screenshot 2023-06-21 at 15.19.29.png     PNG File Top CoV for ops_per_sec, thread_level 1.png    
Issue Links:
Depends
depends on SERVER-85002 Investigate if Bonsai + sampling CE p... Closed
is depended on by SERVER-78073 Make bonsai sampling variants run weekly Closed
Related
Assigned Teams:
Query Optimization
Backwards Compatibility: Fully Compatible
Sprint: QO 2023-06-12, QO 2023-06-26
Participants:

 Description   

As a result of investigation work, it looks like sampling CE generates variable plans.

Svilen's suggestion on the scope was to make sampling to read only from the beginning of the collection, rather than getting a true $sample (on the performance variants). We could hide this behaviour behind an internal test-only query knob in order to increase testing stability.

If this still does not eliminate the variability, we can consider disabling the most variable workloads, or disabling the sampling variants entirely.



 Comments   
Comment by Githook User [ 23/Jun/23 ]

Author:

{'name': 'Alya Berciu', 'email': 'alya.berciu@mongodb.com', 'username': 'alyacb'}

Message: SERVER-77510 Reduce Bonsai sampling variability in perf variants
Branch: master
https://github.com/mongodb/mongo/commit/ed4bc05471a1d9fa9b9a83b3134ce6a0c15d90e4

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