Gartner cites PostgreSQL as the leading open source database. This is because there are no licensing fees for PostgreSQL.

The costs for PostgreSQL are therefore not the license costs, but a migration to a new version or from another database vendor to PostgreSQL is not free. As with the migration of other databases, this involves costs for the deployment of consultants, possibly the purchase of new hardware, etc. The management and maintenance of PostgreSQL is also essential for the proper functioning of your database. This includes installing the latest patches and monitoring your environment.