pg进程

bgwriter:

http://book.51cto.com/art/201201/313208.htm

autovacuum:

http://book.51cto.com/art/201201/313211.htm

http://www.postgresql.org/docs/9.2/static/routine-vacuuming.html#AUTOVACUUM

walwriter:

http://book.51cto.com/art/201201/313209.htm

pgarch:

http://book.51cto.com/art/201201/313210.htm

checkpoint, logger process(写csv日志)进程：

http://blog.163.com/digoal@126/blog/static/1638770402013568653116/

http://www.cnblogs.com/gaojian/archive/2012/10/24/2737068.html