Just by looking into the code SQLite wins. Although Level DB is not fully conformant SQL database. Still there is no comparison.
Also Wikipedia Leveld DB article makes me wonder. This looks to me like Jeff and Sanjay "playground project". The worst (for me) is it is C++ and not C code.
Perhaps you need to read this before deciding on Level DB. LMDB seems the way to go. Funny thing is I have not found any Jeff or Sanjay comment on LMDB yet?
Google code with very minimal "make it run" adjustments.
For TESTING purposes, this code depends on UBUT part of the MACHINE_WIDE dbj suite.
Basically this is "counter effort" :) I "need" to prove implementing KV storage on top of SQLite as the most feasible solution. Not performant buf feasible. Mind you, currently and right now, I have very minimal knowledge about this API.
Only C API is used, as defined in leveldb/c.h
leveldb is built as static lib. Release build optimizations might come latter.