BEP-404: Clear Miner History when Switching Validators Set (bnb-chain…

…#404)

BEPs/BEP-404.md

@@ -0,0 +1,54 @@
+<pre>
+  BEP: 404
+  Title: Clear Miner History when Switching Validators Set
+  Status: Candidate
+  Type: Standards
+  Created: 2024-07-01
+</pre>
+
+# BEP-404: Clear Miner History when Switching Validators Set
+
+- [BEP-404: Clear Miner History when Switching Validators Set](#bep-404-clear-miner-history-when-switching-validators-set)
+  - [1. Summary](#1-summary)
+  - [2. Motivation](#2-motivation)
+  - [3. Status](#3-status)
+  - [4. Specification](#4-specification)
+  - [5. Backwards Compatibility](#5-backwards-compatibility)
+  - [6. License](#6-license)
+
+## 1. Summary
+After switching the validator set on the BSC chain, the previous block production record is still used to restrict some validators from producing blocks for the first few blocks after the switch, leading to brief network instability. This BEP aims to resolve this issue.
+
+## 2. Motivation
+The validator set on the BSC chain switches at each epoch.
+
+Assume the number of validators in an epoch is validatorN. To ensure the consistency of the BSC chain, it is required that the chain must have at least validatorN/2+1 validators to continue advancing the chain.
+
+To achieve this constraint, a set called MinerHistory is defined, with a length of validatorN/2, recording the validators that produced the last validatorN/2 blocks. New block-producing validators are required to not be in MinerHistory.
+
+This BEP aims to enhance network stability by clearing MinerHistory when the validator set switches.
+
+## 3. Status
+This BEP is in progress.
+
+## 4. Specification
+In the previous specification, when the validator set switches at each epoch, MinerHistory is not cleared, causing some validators to be unable to produce blocks normally for the first few blocks after the switch.
+<div align="center">
+<img src=./assets/BEP-404/4-1.png width=100% />
+</div>
+This BEP clarifies that MinerHistory should be cleared when switching the validator set to solve this issue.
+
+```Go
+MinerHistory  map[uint64]Address  
+
+// The conditions for switching remain unchanged
+if BlockNum % EpochLength == (validatorN/2) {
+  MinerHistory = Address{}
+}
+```
+
+## 5. Backwards Compatibility
+There are no known backward compatibility issues.
+
+## 6. License
+The content is licensed under [CC0](https://creativecommons.org/publicdomain/zero/1.0/)

README.md

@@ -73,6 +73,7 @@ Here is the list of subjects of BEPs:
 | [BEP-362](./BEPs/BEP-362.md) | Greenfield Storage Fee Paymaster                          | Standards | Candidate |
 | [BEP-364](./BEPs/BEP-364.md) | Primary Storage Provider acts as the upload agent for object creation and update on Greenfield | Standards | Candidate |
 | [BEP-366](./BEPs/BEP-366.md) | PGreenfield Atomic Object Update                           | Standards | Candidate |
+| [BEP-404](./BEPs/BEP-404.md) | Clear Miner History when Switching Validator Set          | Standards | Candidate |