Greenplum database is the world’s leading open-source MPP database. MPP database means a distributed system. They very first thing you have to deal with in distributed system is that how to divide data into pieces and split them around machines. Greenplum supports different kinds of data distribution policy: hash, random, replicated. Among these kinds of policy, hash-distribution is the most important one since many intermediate results are hash-distributed. Please visit https://greenplum.cn/ for more details.