Regarding use case of epoch to generate nanoseconds precision

Postgres supports only upto microseconds (6 decimal precision).

How do we generate timestamp with nanoseconds as rds postgres not supported timestamp9 extension ?

Is there a way to generate timestamp with nanoseconds precision on pg_partman with epoch without typecasting or with typecasting  ?

p_epoch =>   (to_timestamp(control column))

Here what is the control column?

How to run it with the create_parent function of partman?

Here as per the pg_partman doc 

p_epoch - tells pg_partman that the control column is an integer type, but actually represents an epoch time value. Valid values for this option are: 'seconds', 'milliseconds', 'nanoseconds', and 'none'. The default is 'none'. All table names will be time-based. In addition to a normal index on the control column, be sure you create a functional, time-based index on the control column (to_timestamp(control column)) as well so this works efficiently.

Regards,

Durga Mahesh Manne