Suggest: supports on-demand opening and closing

[stevobm]

It will be perfect if LMDB supports on-demand opening and closing: automatically opening when the database is accessed and automatically closing when it is not in use.

[kriszyp]

It actually already does this, automatically closing the DB on destruction in GC.

I am not sure if that aligns with what you mean by "accessed" and "not in use" though. I'm guessing you actually also want to have an API/function that can retrieve any currently-open db, if it exists, through a weak reference (that allows collection if "not in use"), and opening one otherwise (this can be done with a weakly-valued map).

[stevobm]

Actually, I wish the .mdb file to be unlocked once the data is writen. Now, the file is locked until the rootDB.close() is called.