The Arrow Feather format is an on-disk representation of Arrow memory. To read a Feather file, Arrow just copies it byte for byte from disk into memory. Or Arrow can memory-map a Feather file so you can operate on it without reading the whole file into memory.
The advantage you describe is in the operations that can performed against the data. It would be nice to see what this API looks like and how it compares to flatbuffers / pq.
To help me understand this benefit, can you talk through what it's like to add 1 to each record and write it back to disk?
