1. A method for realizing graph processing based on the MapReduce architecture, comprising: receiving an input file of a graph processing job; predicting a MapReduce task execution time distribution of the graph processing job using an obtained MapReduce task degree-execution time relationship distribution and a degree distribution of the graph processing job, wherein: for a Map task degree-execution time relationship distribution, the predicting of the a MapReduce task execution time distribution includes predicting a Map task execution time distribution of the graph processing job using the Map task degree-execution time relationship distribution and a degree distribution of the graph processing job; and for a Reduce task degree-execution time relationship distribution, the predicting of the a MapReduce task execution time distribution includes predicting a Reduce task execution time distribution of the graph processing job using the Reduce task degree-execution time relationship distribution and a degree distribution of the graph processing job; and dividing the input file of the graph processing job into input data splits of MapReduce tasks according to the predicted MapReduce task execution time distribution of the graph processing job, wherein dividing the input file of the graph processing job into input data splits of MapReduce tasks includes: detecting whether key-value pairs of nodes in the input file of the graph processing job are construed with degrees of the nodes; responsive to detecting that the key-value pairs of nodes in the input file are constructed with degrees of the nodes, sorting the key-value pairs of the nodes according to the degrees; dividing the sorted key-value pairs of the nodes into substantially equal input data splits of MapReduce tasks according to the predicted MapReduce task execution time distribution of the graph processing job; and assigning the input data splits of the Map tasks to Map Task Trackers to execute and the input data splits of the Reduce tasks to Reduce Task Trackers to execute.