If your database suffers a problem at 15:22 p.m. and yet your backup was taken at 04:00 a.m. you're probably hoping there is a way to recover the changes made between those two times. What you need is known as "point-in-time recovery".
Regrettably, if you've made a backup with
pg_dump at 04:00 a.m. then you won't be able to recover to any other time than 04:00. As a result, the term point-in-time recovery (PITR) has become synonymous with the physical backup and restore technique in PostgreSQL.
If you have a backup made with
pg_dump, then give up all hope of using that as a starting point for a point in time recovery. It's a frequently asked question, but the answer is still "no"; the reason it gets asked ...