The 24 is the storage overhead per row in a table is fixed for all tables ot it varies? I wanted to know whether the storage overhead per row in atable is fixed for all tables created irrespective of given datatypes or it varies from one table to another?
The table row layout describes a header of 23 bytes for each table row, and that is independent of the data types.
One item that is variable is the “null bitmap” that is technically part of the row data: it is only present if there is a nullable column in the table. Yet another reason to define most columns as NOT NULL!