Hi, I was reading around the rust-arrow codebase, evaluating it for potential future use. I'm particularly interested in zero-copy processing.
I could very well be wrong here, as I don't have a lot of rust experience, but it looks like the code for reading buffers out of IPC messages is copying the contents of the data. A buffer is constructed via Buffer::from(&[u8]) according to an ipc::Buffer object here: https://github.com/apache/arrow/blob/8e43f23dcc6a9e630516228f110c48b64d13cec6/rust/arrow/src/ipc/reader.rs#L39 The Buffer::from method is defined here: https://github.com/apache/arrow/blob/8e43f23dcc6a9e630516228f110c48b64d13cec6/rust/arrow/src/buffer/immutable.rs#L222 and appears to create an empty buffer, then copy data from the slice into it. As far as I'm aware, the C++ implementation of arrow does not copy buffer data out of IPC messages in this way. Is my understanding correct? Are there additional considerations in rust which means it's not possible for objects accessed by application code (e.g. record-batches, arrays) to keep their buffers in IPC messages? Thanks, Al
