MapDB is great, thank you for creating and supporting it!

But I think the most important feature of it is that it implements common Java interfaces from java.util.concurrent like ConcurrentMap. Drop-in in a best sense of the word.

I'm not very familiar with Golang ecosystem, but my impression that it lacks in this department (of common interfaces).

This tree is implemented as the record position informations indexing container for a disk-based storage engine on the bitcask model..

And the memory are expensive in that case..