Priority: Major - P3
Affects Version/s: 4.2.3, 4.0.16
Fix Version/s: None
Running YCSB it was possible to identify a performance regression around 18% for MongoDB 4.0 and 4.2 for read operations compared to 3.6.
The test used:
The tests were run on t2.xlarge machines on AWS where the conditions below were met:
3 - mongoD
1- config server
1- mongoS + YCSB
The dataset fits in memory and there was no resource contention.
Using perf(attached the flame graph) it seems that transaction features are the culprit.