The PostgreSQL faithful would say that their favorite database was always a viable alternative to Oracle, but it took the European Commission to catapult the open-source project into the spotlight.

In clearing the way for Oracle’s acquisition of Sun Microsystems, the EC removed the final anti-competitive roadblock to the deal by saying that the PostgreSQL database was robust enough to offer an open-source choice to Oracle’s database offerings.

Now, a month after the close of the deal,  Oracle is promising MySQL’s future will include a larger budget and more innovation. In spite of those promises, inquiries into PostgreSQL migration have increased since the acquisition, as has interest in other open-source alternatives to Oracle and Sun products.

In January of 2009, EnterpriseDB’s MySQL-to-PostgreSQL migration tool saw 5,000 downloads. In November, as the deal was hung up by the EC, that number increased to 8,100. Ed Boyajian, CEO of EnterpriseDB, said that this increase reflects the growth in the number of customers that have approached his company to learn more about replacing MySQL.

“Q4 2009 was our largest new customer quarter in the history of the company by almost a factor of two over the next closest quarter,” said Boyajian. “The EU rightly recognized PostgreSQL as the alternative database for the open-source users.”

Despite the warnings of failure from Oracle’s competitors, there is  precedent for the company succeeding with open-source database acquisitions. Mike Olson founded Sleepycat to support the Berkeley DB embedded XML database. In February of 2006, Oracle purchased that company for an undisclosed amount. Today, Olson is CEO of Cloudera, and he said he’s one of only a few Sleepycat employees not still working at Oracle.

“The first thing I would say is that I spent a couple of really great years at Oracle,” he said. “By far, the majority of Sleepycat’s employees are still working at Oracle in engineering, sales and marketing in general, doing the same jobs they were before. It was a change to go from this scrappy, tiny company to one of the biggest enterprises on the planet, but it’s one everyone made it through.

“I liked the people I worked with at Oracle a great deal. I think the strategy Oracle’s exhibited in growing the customer base through internal investment and through mergers and acquisitions has been hugely successfully.”