Storage

Get database sizes

select pg_size_pretty(pg_database_size('<database name>'));

Get table sizes

select pg_size_pretty(pg_total_relation_size(relid)) as total_size
     , pg_size_pretty(pg_relation_size(relid, 'main')) as relation_size_main
     , pg_size_pretty(pg_relation_size(relid, 'fsm')) as relation_size_fsm
     , pg_size_pretty(pg_relation_size(relid, 'vm')) as relation_size_vm
     , pg_size_pretty(pg_relation_size(relid, 'init')) as relation_size_init
     , pg_size_pretty(pg_table_size(relid)) as table_size
     , pg_size_pretty(pg_total_relation_size(relid) - pg_relation_size(relid)) as external_size
  from pg_catalog.pg_statio_user_tables
 where schemaname = '<database name>'
   and relname like '<table name>';