TIP-550: P2P message snappy compression

[jwrct]

Tip: 550
Title: P2P message snappy compression
Author: allen.cheng@tron.network
Status: Final
Type: Standards Track
Category: Networking
Date: 2023-05-22

Simple Summary

This TIP proposes a small extension to the TRON protocol to enable Snappy compression on all message payloads after the initial handshake.

Abstract

The base networking protocol used by TRON currently does not employ any form of compression. This results in a massive amount of bandwidth wasted in the entire network, making both initial sync and regular operation slower and laggier. This situation can be improved by compressing network messages. After extensive benchmarks, the results show that data traffic is decreased by 40-60% for block synchronization.

Motivation

Currently, the block size of the TRON ​​network is around 80k bytes. And as the TRON ​​network continues to grow, the block size may continue to increase, the network load will also increase, and the bandwidth requirements of nodes will also increase. However, most data (blocks, transactions) are highly compressible. By enabling compression at the message payload level, we can reduce the amount of data transmitted by the message, reducing bandwidth usage and data synchronization latency.

Rationale

Enable Snappy compression on all TCP channel message payloads after the initial handshake. Compress the message before sending it through the channel. When receiving a compressed message, decompress it first and then continue the subsequent business processing. The handshake message is never compressed, since it is needed to negotiate the common version.

Specification

Pack the compressed message into CompressMessage for network transmission. The structure of CompressMessage is as follows:

message CompressMessage {
  enum CompressType {
    uncompress = 0;
    snappy = 1;
  }
  CompressType type = 1;
  bytes data = 2;
}

Implementation

Snappy dependency

implementation group: 'org.xerial.snappy', name: 'snappy-java', version: '1.1.8.4'

Compression implementation when sending messages:

public void send(Message message) {
  if (finishHandshake) {
    data = ProtoUtil.compressMessage(message.getSendData()).toByteArray();
  }
  ...
}

public static Connect.CompressMessage compressMessage(byte[] data) throws IOException {
    Connect.CompressMessage.CompressType type = Connect.CompressMessage.CompressType.uncompress;
    byte[] bytes = data;

    byte[] compressData = Snappy.compress(data);
    if (compressData.length < bytes.length) {
      type = Connect.CompressMessage.CompressType.snappy;
      bytes = compressData;
    }

    return Connect.CompressMessage.newBuilder()
            .setData(ByteString.copyFrom(bytes))
            .setType(type).build();
  }

Decompression implementation when receiving a compressed message:

@Override
protected void decode(ChannelHandlerContext ctx, ByteBuf buffer, List<Object> out) {
    byte[] data = new byte[buffer.readableBytes()];
    buffer.readBytes(data);
    if (channel.isFinishHandshake()) {
      data = ProtoUtil.uncompressMessage(Connect.CompressMessage.parseFrom(data));
    }
    ...
}

public static byte[] uncompressMessage(Connect.CompressMessage message) throws IOException {
    if (message.getType().equals(Connect.CompressMessage.CompressType.uncompress)) {
      return message.getData().toByteArray();
    } else {
      return Snappy.uncompress(message.getData().toByteArray());
    }
}

Backward Compatibility

This proposal is fully backward compatible. Clients upgrading to the proposed new version protocol should still support skipping the compression step for older version protocol connections.

Test

Download blocks with block heights from 46314350 to 46314360, and perform a compression and decompression test. The compression rate is about 51%. The specific test results are as follows:

Block size (byte)	Compressed size (byte)	Compression rate	Compression/decompression time（ms）
89803	44361	0.50	<1
104504	50926	0.51	<1
70970	35247	0.50	<1
96544	46905	0.51	<1
82820	41005	0.50	1
83987	41878	0.50	<1
82296	40566	0.51	<1
77820	39108	0.50	<1
73715	36027	0.51	<1
90632	43918	0.52	<1

[Ocea91]

wow, this will basically slash the disk space needed in half. When will this release?

[L-Reid]

wow, this will basically slash the disk space needed in half. When will this release?

This may not decrease the disk occupation, What I understand is that it is only compressed the message when the message is transmitted which reduced the bandwidth usage. Will this speed up the block synchronization?

[jwrct]

wow, this will basically slash the disk space needed in half. When will this release?

This may not decrease the disk occupation, What I understand is that it is only compressed the message when the message is transmitted which reduced the bandwidth usage. Will this speed up the block synchronization?

Yes, you are right. From a global perspective, reducing bandwidth usage will speed up block synchronization.

[jwrct]

wow, this will basically slash the disk space needed in half. When will this release?

It will be released in the next version, the exact date is not yet confirmed, but soon.

[Jamestepfoward]

Good job, just that why you suggest using Snappy compression sdk, have you compared with other similar compression method such as Zstd? I just wonder the process you decide to choose Snappy, I mean if we want to optimize it, it's better to use the best one right?

[jwrct]

Good job, just that why you suggest using Snappy compression sdk, have you compared with other similar compression method such as Zstd? I just wonder the process you decide to choose Snappy, I mean if we want to optimize it, it's better to use the best one right?

When choosing a compression method, we compared the performance of various compression methods, and in the end we decided to choose the same compression method used by Ethereum. Of course, we will continue to test different compression methods. If the advantages are obvious, we will consider supporting multiple compression methods later.

[Bellgin]

I would say thank you for the test stats, they seem convincible. Catching up Eth with the same method would shovel loads of work.

[ikirudoughnuts]

Cutting off 51% of the redundant message size, a surprisingly good one, this should be a mandatory update.

[jwrct]

Close this issue as it is implemented by GreatVoyage-v4.7.2.
Check TIP detail at TIP-550
Check implementation PR at tronprotocol/libp2p#7