Hi, I am processing an RDD of key-value pairs. The key is an user_id, and the value is an website url the user has ever visited.
Since I need to know all the urls each user has visited, I am tempted to call the groupByKey on this RDD. However, since there could be millions of users and urls, the shuffling caused by groupByKey proves to be a major bottleneck to get the job done. Is there any workaround? I want to end up with an RDD of key-value pairs, where the key is an user_id, the value is a list of all the urls visited by the user. Thanks, Jianguo
