1、查看某个数据库大小：

select pg_database_size('log_analysis');

查看多个数据库大小：

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

3、按顺序查看索引

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

4、查看所有表的大小

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