Polygon Pos Hard Fork

Polygon finished the hard fork on January 17th, 2023, Tuesday to address the issue with gas spikes and chain reorganisation.

What is it?
Need for Hard Fork
Conclusion

What is it?

The Polygon validators Team is of 15 voters, which recently participated in voting to change the BaseFeeChangeDenominator and SprintLength functions in reducing instances of spiking gas fees and disruptive chain reorganisations.

Out of these 15 validator voters, 87 % were in favour of increasing the BaseFeeChangeDenominator from 8 to 16 and decreasing the SprintLength from 64 blocks to 16.

There were two proposals made in this Hard Fork.

The first proposal works on a mechanism that sets gas fees. The goal of this mechanism is to keep gas prices low when there is a lot of activity on the network.

The second proposal aims to lower the time it takes to complete a block, which occurs when a validator node receives information that temporarily creates a new version of the blockchain.

Need for Hard Fork

To include a transaction in a block, gas fees are required. There is a "base fee" according to EIP-1559 which is the minimum fee for including blocks. When the chain is busy, gas fees experience exponential spikes. These spikes are often referred to as gas spikes. The number of blocks a validator produces contiguous blocks on the Bor chain is known as "Sprint Length".

In the second proposal when a validator node receives data that creates a new version of the blockchain then due to such a process it is difficult to properly verify if a transaction has been successful since nodes will need to reconcile which chain is the correct one.

Chain reorganisations occur when a validator node receives new data that shows a longer chain, or higher version of the chain. The chain with the highest data is referred to as the “canonical” chain. The old chain should be discarded if a longer version of the chain arrives with more blocks, also called the canonical chain. This Chain reorganisation impacts transaction finality and disrupts the ability of an application to be confident that its transactions are part of the canonical version of the chain.

Conclusion

Through this, the base gas fee rate will fall to 6.25% (100/16) from the current 12.5% (100/8). In the first proposal, although the gas price will still increase when there is high demand, the goal is to smooth severe fluctuations in gas spikes.

To improve transaction finality, the hard fork will decrease the sprint length. This will allow single-block validators to continuously add blocks at a frequency of 32 seconds in place of 128 seconds. However, the chain reorganisation process must be done as effectively as possible to reduce the risk of a 51 percent attack.