@ryoqun @sakridge @jeffwashington wdyt, would this work here? the initial design had a snapshot slot that would keep the data behind that slot form being cleaned up as the index is updated. So we shouldn't need a global lock on all the keys to do the snapshot.

Why do you grow the `DataBucket` cell_size exponentially?

I guess in the future this could recycle old MMaps instead of remove_file below

Could you clarify if capacity is in units of cell_size, or bytes? Edit: I believe it’s cell_size.