combine pgreplay with pgBadger
pgreplay, written by Laurenz Albe, reads a PostgreSQL log file, extracts the SQL statements and executes them in the same order and with the original timing against a PostgreSQL database.
While pgreplay will find out if your database application will encounter performance problems, it does not provide a lot of help in the analysis of the cause of these problems. Combine pgreplay with a specialized analysis program like pgBadger (https://github.com/dalibo/pgbadger) for that.