It’s actually in the manual so this is not exactly a secret, but I managed to overlook it so perhaps I’m not the only one…

In our specific scenario, db4o was about 3 times slower than MSSQL via Linq to SQL in the past days.

Just a few minutes ago, I finally read this:

Native Query optimizer for .NET requires the following libraries to work:
Db4obects.Db4o.Instrumentation.dll
Db4objects.Db4o.NativeQueries.dll
Mono.Cecil.dll
Cecil.FlowAnalysis.dll

(see http://developer.db4o.com/Documentation/Reference/db4o-7.12/net35/reference/html/reference/tuning/native_query_optimization.html)

I added these dll’s to my solution and wooosh! Now it’s up to 50 times faster than before! That’s what I needed… Will see how this works with larger data sets…

Update: There have been some important changes in builds past 14021, see my more recent post on that topic. In short, the new kid in town is Mono.Reflection.dll, which took Cecil’s place.