Warning: postgresql "database_name"
Not all the data was backed up into ......... successfully. /usr/lib/postgresql/9.5/bin/pg_dump: invalid option -- 'i' Try "pg_dump --help" for more information.
Same problem here. I'm using PostgreSQL 9.5, and Plesk can manage it, but backups do not work, via Plesk Backup Manager or via phpPgAdmin. They suggested me to upgrade to Plesk Onyx, but the problem still occurs.