I wanted to love berkeley db; it was available everywhere, seemed simple, was fast when tested. In practice it never worked well though, with pretty frequent corruption under load, and license confusion from oracle. It has a lot of features you're never going to use, and if you try, you'll be disappointed

There's no shortage of embeddable key-value stores with C bindings like leveldb, rocksdb, or even gdbm, and all of them have worked better for me.