tendermint/spec/reactors/mempool/reactor.md

Mempool Reactor

Channels

See this issue

Mempool maintains a cache of the last 10000 transactions to prevent replaying old transactions (plus transactions coming from other validators, who are continually exchanging transactions). Read Replay Protection for details.

Sending incorrectly encoded data or data exceeding maxMsgSize will result in stopping the peer.

maxMsgSize equals MaxBatchBytes (10MB) + 4 (proto overhead). MaxBatchBytes is a mempool config parameter -> defined locally. The reactor sends transactions to the connected peers in batches. The maximum size of one batch is MaxBatchBytes.

The mempool will not send a tx back to any peer which it received it from.

The reactor assigns an uint16 number for each peer and maintains a map from p2p.ID to uint16. Each mempool transaction carries a list of all the senders ([]uint16). The list is updated every time mempool receives a transaction it is already seen. uint16 assumes that a node will never have over 65535 active peers (0 is reserved for unknown source - e.g. RPC).