After understanding more about the context, I feel https://gist.github.com/mad/df729c6a27a7ed224820cdd27209bade is not a fair comparison between iterator and iterable versions because it assumes all entries are loaded once in memory, which isn't necessarily true in real-world scenarios where the input is an AsyncResultSet that uses paging.

The benefit of the iterator version is to avoid pre-allocate a huge chunk of memory for the byte array. I found some flaws in it (reported at https://github.com/JanusGraph/janusgraph/issues/2524#issuecomment-808857502) but not sure whether that is the root cause or not.

@sergey, do you see any OOM exception when you encounter the issue (JG eats all the memory and becomes unresponsive)? If you could share a heap dump, that would be very helpful as well.

Best regards,
Boxuan