Why Apache IoTDB's Internal memory in java Native Memory Tracking is too high?

The Internal memory section in java Native memory tracking takes too much memory may caused by off heap memory like DirectByteBuffer. In IoTDB, we indeed used FileChannel to do io stuff which used DirectByteBuffer in itself and we alse limit that in conf/iotdb-env.sh

-XX:MaxDirectMemorySize=${MAX_DIRECT_MEMORY_SIZE}

So it should be normal, don't worry about that.

The above statements can be verified by https://gist.github.com/prasanthj/48e7063cac88eb396bc9961fb3149b58.