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Posted to github@arrow.apache.org by GitBox <gi...@apache.org> on 2022/06/15 11:03:34 UTC
[GitHub] [arrow-rs] martin-g commented on a diff in pull request #1855: support compression for IPC
martin-g commented on code in PR #1855:
URL: https://github.com/apache/arrow-rs/pull/1855#discussion_r897835928
##########
arrow/src/ipc/reader.rs:
##########
@@ -34,13 +35,62 @@ use crate::record_batch::{RecordBatch, RecordBatchReader};
use ipc::CONTINUATION_MARKER;
use DataType::*;
+use crate::ipc::{CompressionType};
+use crate::ipc::compression::compression::CompressionCodecType;
+use crate::ipc::compression::{LENGTH_EMPTY_COMPRESSED_DATA, LENGTH_NO_COMPRESSED_DATA, LENGTH_OF_PREFIX_DATA};
+
/// Read a buffer based on offset and length
-fn read_buffer(buf: &ipc::Buffer, a_data: &[u8]) -> Buffer {
+/// From https://github.com/apache/arrow/blob/6a936c4ff5007045e86f65f1a6b6c3c955ad5103/format/Message.fbs#L58
+/// Each constituent buffer is first compressed with the indicated
+/// compressor, and then written with the uncompressed length in the first 8
+/// bytes as a 64-bit little-endian signed integer followed by the compressed
+/// buffer bytes (and then padding as required by the protocol). The
+/// uncompressed length may be set to -1 to indicate that the data that
+/// follows is not compressed, which can be useful for cases where
+/// compression does not yield appreciable savings.
+fn read_buffer(buf: &ipc::Buffer, a_data: &[u8], compression_codec: &CompressionCodecType) -> Buffer {
let start_offset = buf.offset() as usize;
let end_offset = start_offset + buf.length() as usize;
let buf_data = &a_data[start_offset..end_offset];
- Buffer::from(&buf_data)
+ match compression_codec {
+ CompressionCodecType::NoCompression => {
+ Buffer::from(buf_data)
+ }
+ CompressionCodecType::Lz4Frame | CompressionCodecType::ZSTD => {
+ // 8byte + data
+ // read the first 8 bytes
+ // if the data is compressed, decompress the data, otherwise decompress data.
+ let decompressed_length = read_uncompressed_size(buf_data);
+ if decompressed_length == LENGTH_EMPTY_COMPRESSED_DATA {
+ // emtpy
+ let empty = Vec::<u8>::new();
+ Buffer::from(empty)
+ } else if decompressed_length == LENGTH_NO_COMPRESSED_DATA {
+ // not compress
+ let data = &buf_data[(LENGTH_OF_PREFIX_DATA as usize)..(end_offset - start_offset)];
+ Buffer::from(data)
+ } else {
+ // decompress data using the codec
+ let mut uncompressed_buffer = Vec::new();
+ let input_data = &buf_data[(LENGTH_OF_PREFIX_DATA as usize)..(end_offset - start_offset)];
Review Comment:
```suggestion
let input_data = &buf_data[(LENGTH_OF_PREFIX_DATA as usize)..];
```
##########
arrow/src/ipc/reader.rs:
##########
@@ -34,13 +35,62 @@ use crate::record_batch::{RecordBatch, RecordBatchReader};
use ipc::CONTINUATION_MARKER;
use DataType::*;
+use crate::ipc::{CompressionType};
+use crate::ipc::compression::compression::CompressionCodecType;
+use crate::ipc::compression::{LENGTH_EMPTY_COMPRESSED_DATA, LENGTH_NO_COMPRESSED_DATA, LENGTH_OF_PREFIX_DATA};
+
/// Read a buffer based on offset and length
-fn read_buffer(buf: &ipc::Buffer, a_data: &[u8]) -> Buffer {
+/// From https://github.com/apache/arrow/blob/6a936c4ff5007045e86f65f1a6b6c3c955ad5103/format/Message.fbs#L58
+/// Each constituent buffer is first compressed with the indicated
+/// compressor, and then written with the uncompressed length in the first 8
+/// bytes as a 64-bit little-endian signed integer followed by the compressed
+/// buffer bytes (and then padding as required by the protocol). The
+/// uncompressed length may be set to -1 to indicate that the data that
+/// follows is not compressed, which can be useful for cases where
+/// compression does not yield appreciable savings.
+fn read_buffer(buf: &ipc::Buffer, a_data: &[u8], compression_codec: &CompressionCodecType) -> Buffer {
let start_offset = buf.offset() as usize;
let end_offset = start_offset + buf.length() as usize;
let buf_data = &a_data[start_offset..end_offset];
- Buffer::from(&buf_data)
+ match compression_codec {
+ CompressionCodecType::NoCompression => {
+ Buffer::from(buf_data)
+ }
+ CompressionCodecType::Lz4Frame | CompressionCodecType::ZSTD => {
+ // 8byte + data
+ // read the first 8 bytes
+ // if the data is compressed, decompress the data, otherwise decompress data.
Review Comment:
```suggestion
// if the data is compressed, decompress the data, otherwise return as is
```
##########
arrow/src/ipc/writer.rs:
##########
@@ -37,6 +38,9 @@ use crate::record_batch::RecordBatch;
use crate::util::bit_util;
use ipc::CONTINUATION_MARKER;
+use crate::ipc::{BodyCompressionMethod, CompressionType};
+use crate::ipc::compression::compression::CompressionCodecType;
+use crate::ipc::compression::{LENGTH_EMPTY_COMPRESSED_DATA, LENGTH_OF_PREFIX_DATA};
Review Comment:
```suggestion
use crate::ipc::compression::{LENGTH_EMPTY_COMPRESSED_DATA, LENGTH_OF_PREFIX_DATA, LENGTH_NO_COMPRESSED_DATA};
```
##########
arrow/src/ipc/writer.rs:
##########
@@ -912,19 +945,64 @@ fn write_array_data(
}
/// Write a buffer to a vector of bytes, and add its ipc::Buffer to a vector
+/// From https://github.com/apache/arrow/blob/6a936c4ff5007045e86f65f1a6b6c3c955ad5103/format/Message.fbs#L58
+/// Each constituent buffer is first compressed with the indicated
+/// compressor, and then written with the uncompressed length in the first 8
+/// bytes as a 64-bit little-endian signed integer followed by the compressed
+/// buffer bytes (and then padding as required by the protocol). The
+/// uncompressed length may be set to -1 to indicate that the data that
+/// follows is not compressed, which can be useful for cases where
+/// compression does not yield appreciable savings.
fn write_buffer(
buffer: &Buffer,
buffers: &mut Vec<ipc::Buffer>,
arrow_data: &mut Vec<u8>,
offset: i64,
+ compression_codec: &CompressionCodecType
) -> i64 {
- let len = buffer.len();
- let pad_len = pad_to_8(len as u32);
- let total_len: i64 = (len + pad_len) as i64;
+ let origin_buffer_len = buffer.len();
+ let mut compression_buffer = Vec::<u8>::new();
+ let (data, uncompression_buffer_len) = match compression_codec {
+ CompressionCodecType::NoCompression => {
+ // this buffer_len will not used in the following logic
+ // If we don't use the compression, just write the data in the array
+ (buffer.as_slice(), origin_buffer_len as i64)
+ }
+ CompressionCodecType::Lz4Frame | CompressionCodecType::ZSTD => {
+ if (origin_buffer_len as i64) == LENGTH_EMPTY_COMPRESSED_DATA {
+ (buffer.as_slice(), 0)
+ } else {
+ compression_codec.compress(buffer.as_slice(), &mut compression_buffer).unwrap();
+ if compression_buffer.len() > origin_buffer_len {
+ // the length of compressed data is larger than uncompressed data
+ // use the uncompressed data with -1
+ // -1 indicate that we don't compress the data
+ (buffer.as_slice(), -1)
Review Comment:
```suggestion
(buffer.as_slice(), LENGTH_NO_COMPRESSED_DATA)
```
##########
arrow/src/ipc/reader.rs:
##########
@@ -34,13 +35,62 @@ use crate::record_batch::{RecordBatch, RecordBatchReader};
use ipc::CONTINUATION_MARKER;
use DataType::*;
+use crate::ipc::{CompressionType};
+use crate::ipc::compression::compression::CompressionCodecType;
+use crate::ipc::compression::{LENGTH_EMPTY_COMPRESSED_DATA, LENGTH_NO_COMPRESSED_DATA, LENGTH_OF_PREFIX_DATA};
+
/// Read a buffer based on offset and length
-fn read_buffer(buf: &ipc::Buffer, a_data: &[u8]) -> Buffer {
+/// From https://github.com/apache/arrow/blob/6a936c4ff5007045e86f65f1a6b6c3c955ad5103/format/Message.fbs#L58
+/// Each constituent buffer is first compressed with the indicated
+/// compressor, and then written with the uncompressed length in the first 8
+/// bytes as a 64-bit little-endian signed integer followed by the compressed
+/// buffer bytes (and then padding as required by the protocol). The
+/// uncompressed length may be set to -1 to indicate that the data that
+/// follows is not compressed, which can be useful for cases where
+/// compression does not yield appreciable savings.
+fn read_buffer(buf: &ipc::Buffer, a_data: &[u8], compression_codec: &CompressionCodecType) -> Buffer {
let start_offset = buf.offset() as usize;
let end_offset = start_offset + buf.length() as usize;
let buf_data = &a_data[start_offset..end_offset];
- Buffer::from(&buf_data)
+ match compression_codec {
+ CompressionCodecType::NoCompression => {
+ Buffer::from(buf_data)
+ }
+ CompressionCodecType::Lz4Frame | CompressionCodecType::ZSTD => {
+ // 8byte + data
+ // read the first 8 bytes
+ // if the data is compressed, decompress the data, otherwise decompress data.
+ let decompressed_length = read_uncompressed_size(buf_data);
+ if decompressed_length == LENGTH_EMPTY_COMPRESSED_DATA {
+ // emtpy
+ let empty = Vec::<u8>::new();
+ Buffer::from(empty)
+ } else if decompressed_length == LENGTH_NO_COMPRESSED_DATA {
+ // not compress
+ let data = &buf_data[(LENGTH_OF_PREFIX_DATA as usize)..(end_offset - start_offset)];
Review Comment:
```suggestion
let data = &buf_data[(LENGTH_OF_PREFIX_DATA as usize)..];
```
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