Postgres-XC:
http://blog.csdn.net/huguangshanse00/article/details/9636621
http://blog.163.com/digoal@126/blog/static/1638770402013332335933/
http://blog.163.com/digoal@126/blog/static/163877040201331001855771/
http://blog.163.com/digoal@126/blog/static/16387704020133108138729/
http://francs3.blog.163.com/blog/static/4057672720125315352442/
http://francs3.blog.163.com/blog/static/405767272012532308480/