Patent ID: 8392366
Filing Date: 2013-03-05
Classification: G06F

Abstract:
1. A method of maintaining a cluster of computers, comprising: operating a distributed database that maintains a web graph across the cluster of computers; determining a first computer of the cluster of computers in which to store a first update to the web graph based on processing the first update with a first hash function, the first hash function being configured to determine an indication of n indications, wherein n is the number of computers in the cluster of computers; storing an indication of the first update on the first computer; changing the number of computers in the cluster of computers to provide a changed cluster of computers; determining a second hash function in response to changing the number of computers, the second hash function being configured to determine an indication of n+x indications, where n+x is the number of computers in the changed cluster of computers; determining a second computer of the changed cluster of computers in which to store a second update to the web graph based on processing the second update with the second hash function; storing an indication of the second update on the second computer; sending a query to a first and a second computer of the cluster of computers, the query having been processed with the first hash function; sending the query to a first and a second computer of the changed cluster of computers, the query having been processed with the second hash function; receiving a first result of sending the query to the first and the second computer of the cluster of computers; receiving a second result of sending the query to the first and the second computer of the changed cluster of computers; and in response to determining that a time at which the first result was stored in the cluster of computers is more recent than a time at which the second result was stored in the changed cluster of computers, storing the first result in the memory.