Sony Online Entertainment is starting to move away from the Oracle databases that are the foundation of its online games, opting instead for a two-year-old commercial open-source database based on PostGresSQL.

San Diego-based Sony Online offers a number of popular Massively Multi-Player Online Role-Playing Games, or MMORPGs, including EverQuest, EverQuest 2, Star Wars Galaxies and others.

They have "hundreds of thousands" of subscribers, said Rick Herman, vice president of business and legal affairs at Sony Online Entertainment.

The databases store terabytes of data about the "worlds" in which game characters live, battle and fall in love.

"If you took a virtual character in EverQuest and had him start running in one direction, it would take 30 days before he would reach the end of the world," Herman said.

The games also store data on players' characters. In Star Wars Galaxies, for instance, every object -- be it light sabre, X-Wing fighter,or blaster gun -- can be heavily customized by its owner. That means the database must store each object in the game individually, rather than storing one version that it doles out to every player.

Sony Online now operates more than 150 Oracle 9i databases around the world.

But by mid-year, Sony Online expects to have three services moved to EnterpriseDB's Advanced Server 8.1 database, according to Chris Yates, Sony Online's vice president of technology.

One will be Sony's so-called "Station Exchange" service that creates an eBay-like marketplace for players of EverQuest and EverQuest 2 to buy and sell online goods such as swords, potions and spells.

The service, which debuted last year, is still small, with less than 1,000 items being auctioned at the end of last week, according to Sony. Even so, buyers pay as much as US$2,000 for digital items.

Sony also plans to move one of its smaller games, Matrix Online, which it bought last summer, to EnterpriseDB. It also plans to move a message board over to EnterpriseDB.

Yates had been looking for an alternative to Oracle for a year. "We think it's a great product, but it's so expensive," he said. "We use a lot of Oracle's advanced features: clusters, materialized views, high transactions. We knew that our alternative needed to be a real database."

Oracle's free express edition was "not a lot of use," said Yates, who also looked at open-source databases such as MySQL and PostGres. He liked the latter's "richness" and its lower price tag. But Yates balked at the costs and hassle of retraining his staff and rewriting the database applications to run on PostGres.

EnterpriseDB, on the other hand, is based on PostGres but offers Oracle compatibility. That helped overcome Yates' concerns.

"Close to 80% to 90% of our applications don't need to be rewritten to use with EnterpriseDB," said David Manifold, director of database services for Sony.

Because of the similarity of EnterpriseDB, training has been minimal so far: three days of classes for the Oracle DBAs and developers. "Most of them have found it to be fairly intuitive," Yates said.

Savings are "hard to quantify at this point in time," he said. "We need to prove it out in production first." While Sony will continue to use Oracle, it will slowly migrate other databases onto EnterpriseDB.

In a related move, Sony also became a minority shareholder in EnterpriseDB, which was founded in 2004. Sony joined in a US$7.5 round of financing along with venture capital firms Charles River Ventures and Valhalla Partners as well as some of EnterpriseDB's original angel investors.

Andy Astor, CEO of EnterpriseDB, said Sony's investment was less than US$1.5 million.