查看数据库表的大小

• pg_relation_size("关系名") - 查看关系大小

   jianingy=# select pg_relation_size("contact");
    pg_relation_size 
   ------------------
              425984
   (1 row)

• pg_size_pretty - human readable的大小输入

   jianingy=# select pg_size_pretty(pg_relation_size("contact"));
    pg_size_pretty 
   ----------------
    416 kB
   (1 row)

• 查看所有public schema里面索引大小，大到小的顺序排列

  select indexrelname, pg_size_pretty(pg_relation_size(indexrelname))
    from pg_stat_user_indexes where 
         schemaname = "public" order by pg_relation_size(indexrelname) desc;

• 查看所有public schema里面表的大小，从大到小顺序排里

  select relname, pg_size_pretty(pg_relation_size(relname))
    from pg_stat_user_tables where
         schemaname = "public" order by pg_relation_size(relname) desc;

取自"http://www.pgsqldb.org/mwiki/index.php/%E6%9F%A5%E7%9C%8B%E6%95%B0%E6%8D%AE%E5%BA%93%E8%A1%A8%E7%9A%84%E5%A4%A7%E5%B0%8F"