  Consistent range-hashing is a technique used in distributed systems, either
directly or as a subroutine for consistent hashing, commonly to realize an even
and stable data distribution over a variable number of resources. We introduce
FlipHash, a consistent range-hashing algorithm with constant time complexity
and low memory requirements. Like Jump Consistent Hash, FlipHash is intended
for applications where resources can be indexed sequentially. Under this
condition, it ensures that keys are hashed evenly across resources and that
changing the number of resources only causes keys to be remapped from a removed
resource or to an added one, but never shuffled across persisted ones. FlipHash
differentiates itself with its low computational cost, achieving constant-time
complexity. We show that FlipHash beats Jump Consistent Hash's cost, which is
logarithmic in the number of resources, both theoretically and in experiments
over practical settings.
