After a three-month investigation by the European Commission, the EU has decided that the acquisition has the "potential to revitalize important assets and create new and innovative products." Of particular concern was Oracle's acquisition of MySQL with reportedly 11 million installations.
By buying Sun, Oracle acquires the world's most widely-used open source database MySQL, which Sun bought in 2008. The Commission concluded that Oracle and MySQL dominate different database market segments. For example, Oracle dominates in the high end, where it competes with IBM and SQL Server and where MySQL has virtually no presence. The Commission also found that there are viable alternatives to MySQL, for example, PostgreSQL (which underlies PostGIS) and which is a more competitive open source alternative to Oracle's RDBMS than MySQL.
In the spatial market, Oracle Spatial and PostGIS are probably the leading spatial database engines, but many RDBMSs now support spatial data including MySQL, SQLServer 2008, Ingres, and several IBM RDBMSs.