If you do want a B-tree library in C that's not tied to SQL, I've had good success with lmdb[0]. As a bonus, it's also transactional and writers do not block re

If you do want a B-tree library in C that's not tied to SQL, I've had good success with lmdb[0]. As a bonus, it's also transactional and writers do not block readers (and vice versa). Crazy fast and easier to use from C than SQLite IMO. If you want B-trees that compete with LSM trees, stratified B-trees[1] are pretty sweet. There's an in-kernel GPL implementation called Castle[2] on GitHub. [0] http://symas.com/mdb/ http://symas.com/mdb/ [1] http://www.slideshare.net/acunu/20110620-stratifiedbtree http://www.slideshare.net/acunu/20110620-stratifiedbtree [2] https://github.com/acunu/castle https://github.com/acunu/castle