1、查询所有数据库占用空间大小

SELECT datname, pg_size_pretty(pg_database_size(datname)) AS size FROM pg_database;

2、查询数据库所有表空间占用空间大小

SELECT spcname, pg_size_pretty(pg_tablespace_size(spcname)) AS size FROM pg_tablespace;

3、查询单个数据库表占用空间大小

SELECT pg_size_pretty(pg_total_relation_size('t_audit_log')) AS size;

4、查询所有数据库表占用空间大小

SELECT
    table_schema,
    table_name,
    pg_size_pretty(pg_total_relation_size('"'||table_schema||'"."'||table_name||'"')) as size
FROM information_schema.tables
WHERE table_schema NOT IN ('pg_catalog', 'information_schema')
ORDER BY pg_total_relation_size('"'||table_schema||'"."'||table_name||'"') DESC;