| | |
Summary: Ranged Hash Functions and the Price of Churn
James Aspnes
Muli Safra
Yitong Yin§
Abstract
Ranged hash functions generalize hash tables to the set-
ting where hash buckets may come and go over time, a
typical case in distributed settings where hash buckets
may correspond to unreliable servers or network connec-
tions. Monotone ranged hash functions are a particular
class of ranged hash functions that minimize item reas-
signments in response to churn: changes in the set of
available buckets. The canonical example of a mono-
tone ranged hash function is the ring-based consistent
hashing mechanism of Karger et al. [13]. These hash
functions give a maximum load of n
m log m when n
is the number of items and m is the number of buckets.
The question of whether some better bound could be
obtained using a more sophisticated hash function has
|
