You can restore database from Terminal.

Steps:

1. sudo su postgres
2.createdb database_name --owner=odoo-user --encoding=utf8;

3.psql database_name < databasefile.sql ( .sql file of database backup )

I do noted this issue while restoring Database with size more than 2 GB.

So the alternative for this is just restore it from back-end using the following steps

a) Create a database from the command line ( createdb newdatabase)

b) Alter database owner from postgresql to Odoo

c) Restore DB from raw file ( cat filename | psql newdatabase )

Eg:- cat pg_dump.sql | psql newdatabase