Explanation of Polygon Hard Fork Proposal | Solving Block Reorg and Soaring Gas Fee Issues
Discussion about blockchain reorg and soaring gas fees on Polygon has been ongoing since the end of December last year in the governance forum, as highlighted here. Yesterday, Harry Rook, a developer at Polygon Labs, proposed a governance proposal to address these two issues through a hard fork.
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Delhi Hard Fork: Reducing Block Reorganization
The codename for the Polygon hard fork this time is Delhi, the second-largest city in India, which is mainly divided into two parts:
The main goal of PIP-5 is to securely address the issue of block reorganization on Polygon. Block reorganization mainly occurs due to different client versions, leading to node divergence. Because different nodes reach consensus at different times, previous blocks may be overwritten. This can lead to confusion when trying to verify if a transaction has been successfully completed.
According to observations by the Polygon Labs team, the function of the reorganization length is to reduce the time validators can continuously produce blocks by lowering the Sprint Length. In this case, when validators are offline for a period and come back online, it will only affect one Sprint and the change will occur in the next Sprint.
Therefore, the team proposes to reduce the Sprint Length from 64 blocks to 16 blocks. This change will reduce the time for continuous block production from 128 seconds to around 32 seconds, which is expected to reduce the frequency and depth of reorganizations without affecting the total number of blocks produced by validators.
Note: Sprint Length refers to the number of blocks validators can continuously produce.
Delhi Hard Fork: Lowering Gas Fees
PIP-6 aims to address the issue of rapidly increasing Polygon gas fees, leading to expensive user transaction costs. The team proposes to increase the "BaseFeeChangeDenominator" from 8 to 16. BaseFeeChangeDenominator is a parameter that determines the rate of change in the base fee for transactions based on the current block space demand.
When BaseFeeChangeDenominator is 8 and the network utilization of the previous block is full, the upper limit of the base fee for the next block will be 1.125 times the original fee. If the BaseFeeChangeDenominator is changed to 16, the upper limit of the base fee will be changed to 1.0625 times the original fee.
Therefore, in the case of full block network utilization, with BaseFeeChangeDenominator set at 8, it only takes 20 blocks for the upper limit of the base fee to become 10 times the original fee. On a PoS chain like Polygon, with a block time of just 2 seconds every 40 seconds, the gas fee increases too rapidly. However, by changing the BaseFeeChangeDenominator to 16, under the same conditions, the upper limit of the base fee will only be 3.36 times the original fee, effectively slowing down the rise in gas fees.
Through the above two changes, it is expected to help address the main issues in Polygon's operation. If the proposal is approved by the community, the hard fork upgrade is expected to take place on 1/17.