Hey, I am the author to a Clojure dataframe library, tech.ml.dataset and we are looking to upgrade our ability to handle out-of-memory datasets.
I was hoping to use Arrow for this purpose specifically to have a conversion mechanism where I could stream data into a single Arrow file with multiple record batches and then load that file and mmap each record batch.
The current loading mechanism appears quite poor for this use case; it assumes batch-at-a-time loading by mutating member variables of the root schema and file loading mechanism and it copies each batch into process memory.
It seems to me that, assuming each batch is less than 2 GB, FileChannel.map could be used for each record batch and this would allow one to access data in those batches in a random-access order as opposed to a single in-order traverse and it may allow larger-than-memory files to be operated on.
Is there any interest in this pathway? It seems like Arrow is quite close to realizing this possibility or that it is already possible from nearly all the other languages but the current Java design, unless I am misreading the code, precludes this pathway.
Thanks for any thoughts, feedback,