Yes, there is way to monitor custom parameters in the database by configuring the custom queries.
For example if I want to monitor size of the particular MySQL schema in MB then configure the following query as custom query in MySQL database monitoring page for which I want to monitor. The data will start collecting along with standard MySQL parameters and can be viewed in Custom Parameters section of the database view page.
SELECT ROUND(SUM(data_length + index_length) / 1024 / 1024, 2) AS “Size (MB)” FROM information_schema.TABLES where table_schema = ‘ims’