Comment 1 for bug 1656022

All fractal trees share the same space within the cachetable and other common resources down in PerconaFT. It is a known issue that a drop/delete of tables/indices can take a long time and possibly hold some common locks that might cause other accessors to slow or stall https://tokutek.atlassian.net/browse/FT-715

I can't say for certain if that is what you are seeing but it sounds like a possibility. It would be helpful if we could get a PMP or similar trace when you experience these stalls. It might help point us in some direction.