The pattern match for finding a start point in the stress test's binary search was based on the explain output, and after memory reservations, was never updated. It had a silent failsafe path and chose the memory limit of impalad as a start point instead. This means the binary search, while known to take a long time, is certainly taking longer than it should.
The current pattern is:
Tim Armstrong can you confirm we need to match on the second line here?