Check a size of all tables in PostgreSQL database - MUMT-IT/mis2018 GitHub Wiki
Run this command within PSQL.
select
table_name,
pg_size_pretty(pg_total_relation_size(quote_ident(table_name))),
pg_total_relation_size(quote_ident(table_name))
from information_schema.tables
where table_schema = 'public'
order by 3 desc;