Major - P3 The kWantKey and kJustExistance options for SortedDataInterface::Cursor::RequestedInfo are not really used (the one use of kJustExistance is in code that shouldn't exist), and don't have any benefits today. Moreover they are not tested, and therefore likely to be buggy.
------------------------------------------------------------------------------------------------- Benchmark Time CPU Iterations UserCounters... ------------------------------------------------------------------------------------------------- BM_Advance/AdvanceForwardWantKey 29782742 ns 29782523 ns 24 items_per_second=3.35767M/s BM_Advance/AdvanceForwardWantLoc 18325059 ns 18324732 ns 38 items_per_second=5.45711M/s BM_Advance/AdvanceForwardWantKeyAndLoc 29965805 ns 29964423 ns 23 items_per_second=3.33729M/s BM_Advance/AdvanceForwardJustExistance 18430246 ns 18429362 ns 38 items_per_second=5.42612M/s