The announcement was made in a by the Westford, Mass. database vendor.
Neither EnterpriseDB nor Red Hat immediately responded to requests for comment.
The move is notable because much of Red Hat's current popularity as a server platform is due to users looking to run the free MySQL on top of Red Hat as part of a LAMP (Linux Apache MySQL Python/Perl/PHP) server. EnterpriseDB sells a proprietary, Oracle-compatible database called PostgresPlus that is based around the open-source PostgreSQL technology.
The two companies had reportedly been EnterpriseDB CEO Ed Boyajian is also a former Red Hat vice president.
Boyajian said that the investment, part of a $19 million Series C round of funding, was a "significant amount of money."