Size, audit and rowcount of a table in Vertica
Using below query, you will get the size of Vertica tables.

SELECT anchor_table_schema,
anchor_table_name,
SUM(used_bytes) / (1024 * 1024 * 1024) AS TABLE_SIZE_GB
FROM   v_monitor.projection_storage
GROUP  BY anchor_table_schema,
anchor_table_name
order  by sum(used_bytes) desc;


Check out the most important queries to check table size

https://www.orahow.com/2018/06/how-to-check-size-of-tables-in-vertica.html