环境

centos7，postgres11

查看pg中各个数据库大小

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

查看pg某个数据库中表占用的大小

先选中某个数据库

SELECT
table_name,
pg_size_pretty(table_size) AS table_size,
pg_size_pretty(indexes_size) AS indexes_size,
pg_size_pretty(total_size) AS total_size
FROM (
SELECT
table_name,
pg_table_size(table_name) AS table_size,
pg_indexes_size(table_name) AS indexes_size,
pg_total_relation_size(table_name) AS total_size
FROM (
SELECT ('"' || table_schema || '"."' || table_name || '"') AS table_name
FROM information_schema.tables
) AS all_tables

ORDER BY total_size DESC
) AS pretty_sizes