Greenplum is a based on MVCC architecture that means user’s action like UPDATE will insert a new record in a database.
Greenplum Data warehouse can manage billions of data, but it doesn’t mean that user can generate or UPDATE random data set.
Periodically, The Greenplum DBA should check the size of database schemas and their appropriate usage.

In this post, I shared different scripts to check the size of Greenplum Database Schemas.

Option 1:

select *
from gp_toolkit.gp_size_of_schema_disk;

Option 2:

select
	schemaname
	,round(sum(pg_total_relation_size(schemaname||'.'||tablename))) SchemaSize
from pg_tables group by 1;

Option 3:

SELECT
	schema_name
	,pg_size_pretty(sum(table_size)::bigint)
FROM
(
	SELECT pg_catalog.pg_namespace.nspname as schema_name,
	pg_relation_size(pg_catalog.pg_class.oid) as table_size
	FROM pg_catalog.pg_class
	JOIN pg_catalog.pg_namespace ON relnamespace = pg_catalog.pg_namespace.oid
) t
GROUP BY schema_name
ORDER BY schema_name;