The changes in v0.9.0 have broken CursorIterable for some KeyRange types and keys. I noticed the problem when using KeyRange.atLeastBackward(. The cursor was starting on the wrong key.

I think the problem is this line:

lmdbjava-0.8.3...lmdbjava-0.9.0#diff-a5dda1cdb60b45d45a5a4364768ad1f7c62ac0ec025f295f78d489cf08392bf2R206

It is using the standard java ByteBuffer.compareTo method rather than your lexographical AbstractByteBufferProxy::compareBuff method, so 150 is considered < 110.

See my branch (on the link below) where I have changed your CursorIterableTest to use 200 ... 900 instead of 2 ... 9 for the key values to demonstrate the problem. With the modified values a lot of the tests fail. Changing AbstractByteBufferProxy to use compareBuf makes them all pass again.

https://github.com/lmdbjava/lmdbjava/compare/master...at055612:backwards-at-least?expand=1

I think this is the problem is in AbstractByteBufferProxy.

    @Override
    protected Comparator<ByteBuffer> getComparator(final DbiFlags... flags) {
      final int flagInt = mask(flags);
      if (isSet(flagInt, MDB_INTEGERKEY)) {
        return this::compareCustom;
      }
      return this::compareDefault;
      // TODO Think the above line should be changed to this:
      // return AbstractByteBufferProxy::compareBuff;
    }

It may also be an issue for netty/agrona but I am not using those so have not looked.

This is a pretty serious bug for anyone using KeyRanges and it will present in subtle ways depending on the keys in the db and the keyRange type used.