Number of internal operations for a single DML/DDL

I wanted to know how many internal operations postgres performs for a single DML or DDL statement.

For ex: if I run an insert like insert into emp values(1,'Name'); then one operation postgres does, is it internally updates the pg_stat_*_tables to increase the count of n_tup_ins and n_live_tup for the emp table. 

Apart from these what all operations does postgres do internally, I wanted an average estimated count as I know it would be difficult to get the details for each of the DML/DDL statements

Thanks and Regards,

Nikhil