Postgres: Table list ordered by table size in GB

 SELECT

    table_schema || '.' || table_name AS table_full_name,

    pg_size_pretty(pg_total_relation_size('"' || table_schema || '"."' || table_name || '"')) AS size

FROM information_schema.tables

ORDER BY

    pg_total_relation_size('"' || table_schema || '"."' || table_name || '"') DESC;

for one table:

 SELECT

    table_schema || '.' || table_name AS table_full_name,

    pg_size_pretty(pg_total_relation_size('"' || table_schema || '"."' || table_name || '"')) AS size

FROM information_schema.tables

where table_name = 'batch_job_execution_params';