Hi! (/me being new on this board but a devoted long time Minetest player)
I've wrote a little server called mtredisalize [1] that implements a small
subset of the Redis protocol to serve your LevelDB or SQLite3 worlds directly
as a Redis backend.
The Redis backend is fast and fine but it uses by its nature a lot
of memory. The other both backends are embedded and hard to work with
if want to use them for e.g. mapping.
This software works pretty well and fast for LevelDB databases. The SQLite3
backend works well, too but leaks a bit of memory over time. I'm going to debug this.
Maybe you find the idea interesting. It also offers the oportunity to
play with backends without the need to modify the minetest server all
the time.
To see how to build and have a look at [1].
[1] https://bitbucket.org/s_l_teichmann/mtredisalize