The solution is consistent hashing. Introduced as a term in 1997, consistent hashing was originally used as a means of routing requests among a large number of web servers. It's easy to see how the web could benefit from a hash mechanism that allows any node in the network to efficiently determine the location of an object, in spite of the constant shifting of nodes in and out of the network. This is the fundamental objective of consistent hashing.
With consistent hashing, the buckets are arranged in a ring with a predefined range. The exact range depends on the partitioner being used. Keys are then hashed to produce a value that lies somewhere along the ring. Nodes are assigned a range, which is computed as follows:
|
Range start |
Token value |
|
Range end |
Next token value -1 |
Tip
The following examples assume the default Murmur3Partitioner is used. For more information on this partitioner, take a look at the documentation, which can be found here: http://docs...
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