Streaming Sync & Fast Sync

Fast Sync & Gossips: streaming state sync, information dispersal algorithm

We are replacing gRPC in state sync with p2p streaming with a rate limiter and downloader batch. Later we will implement RapidChain’s gossiping protocol based on an information dispersal algorithm (IDA) for sending large blocks. Both approaches, along with further performance analysis and parameter tuning, will improve our network resiliency and latency.

Current problem at hand:

1. The CPU and memory usage will grow to 100% at the light sail nodes after running for 2~3 days.
2. Some of the in-sync RPCs are redirected to gRPC sync after some iterations of code change.
3. Sometimes, the sync loop is stuck in short-range sync. Need to investigate.

After these three problems being solved, the stream sync protocol can be launched.

Harmony's Networking Story

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2021/10/08

1. Working on stream sync. First looking at the potential memory / CPU leak. Running two machines running customized code on mainnet with stream sync turned on. The customized code include:
1. Frequent discovery call (10s/discovery).
2. Unstable stream sync protocol (injected error in stream sync, occasionally fail)

The result remains to be observed.

2. Finished code revisit and RPC fix concerning stream sync.
3. Next step is to
1. Investigate the CPU / memory leak
2. Spin up stressnet for reproducing the stucking short range sync.