Oracle still leads Database vendors in market share, holding more than 44 percent. But Open Source alternatives may have Oracle worried.Forrester Research recently estimated that the size of the Open Source database market has now reached $850 million and is projected to go to $1.2 billion by 2010. While Open Source databases themselves can be downloaded and used freely, their makers typically earn revenues from training, technical support, and consulting.But in a market that today sees annual sales of $18.8 billion, what’s a billion dollars?It is interesting to note that it won’t be until 2010 that the entire Open Source database market will reach $1 billion — but that’s how much that Sun recently paid when they bought Open Source database maker MySQL. While Oracle leads though, Open Source vendors like Sun are eroding potential sales.Noel Yuhanna of Forrester wrote that “Open source databases have come a long way in delivering reliable, robust; and secure database platforms. Forrester estimates that 80% of application requirements can be met using only 25% of the features and functionality that closed source commercial databases offer.” Yuhanna comments that Open Source databases can meet 80 percent of the functionality most needed by businesses.Vendors creating new applications often write their applications to be able to use any of a variety of database options. It is easy for them to ship a copy of an Open Source database either embedded or as an integrated install with their application. That way installations are seamless and the customer can be up and running immediately with no dependencies on additional software. If the customer later, after test-driving the software, prefers another database, swapping it out can be easily done. The end result is that many pilot views of applications run on Open Source — and if some companies don’t have any problems with their pilots, they may decide to not bother paying the additional money for a commerical database backend.