This query sums total disk space used by the table including indexes and toasted data for the 20 largest tables:
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						SELECT nspname || '.' || relname AS "relation",     pg_size_pretty(pg_total_relation_size(C.oid)) AS "total_size"   FROM pg_class C   LEFT JOIN pg_namespace N ON (N.oid = C.relnamespace)   WHERE nspname NOT IN ('pg_catalog', 'information_schema')     AND C.relkind <> 'i'     AND nspname !~ '^pg_toast'   ORDER BY pg_total_relation_size(C.oid) DESC   LIMIT 20;  |