如何查看表、索引、表空间、数据库大小？

查询一个索引大小

select pg_size_pretty(pg_relation_size('indexname))

查看一张表和它的索引总大小

select pg_size_pretty(pg_total_relation_size('tablename'));

查看所有schema里索引大小，按从大到小排列

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

查看所有schema里表大小，按从大到小排列

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

查看数据库大小

select pg_database.datname,pg_size_pretty(pg_database_size(pg_database.datname)) AS size  
from pg_database;

查看表空间大小

select pg_tablespace_size('tbs_index')/1024/1024  as  "SIZE M";