Published on: 2017-06-12T16:27:14+00:00
The discussion on the bitcoin-dev mailing list revolves around the need for a transaction size limit to address the quadratic hashing problem. Various proposals have been made, including adding a transaction-size limit of 10kb or 100kb, reducing the block size limit to 1MB initially and then dropping it to 500kb or 100kb at a later block height, and implementing a real 2MB block size hardfork following Segwit BIP148 activation.One proposed change suggests enforcing a block size limit of 2,000,000 bytes upon activation, while keeping the block weight limit at 4,000,000 WU. The proposal eliminates the witness commitment in the generation transaction and replaces it with a hash of the witness reserved value, the witness merkle root hash, and the transaction ID merkle root hash. Additionally, the maximum size of a transaction without witness data is limited to 1 MB.Although this proposal is considered risky and is not endorsed by the author, it provides a possible option for a 2 MB block size hardfork following Segwit BIP148 activation. However, deploying this proposal would require consensus from the entire Bitcoin community and is scheduled for 18 months after the creation date of the BIP.The proposed change enforces a block size limit of 2 MB for legacy Bitcoin transactions, with a corresponding block weight limit of 4000000 WU. The calculation of block weight is modified, assigning a weight of 1 WU to all witness data and 4 WU to all other data. As a result, the witness commitment in the generation transaction is no longer required. Instead, the txid merkle root in the block header is replaced with a hash of the witness reserved value, the witness merkle root hash, and the transaction ID merkle root hash.This proposal is set to be deployed on a flag day, which is the block where the median-past time surpasses 1543503872 (2018 Nov 29 at 15:04:32 UTC). It assumes that Segwit has already been activated through BIP141 and/or BIP148. It's important to note that this change represents a hardfork and is not backward compatible. Therefore, it should not be deployed without the consent of the entire Bitcoin community.Activation of this proposal is scheduled for 18 months from the creation date of this BIP. The intention behind this timeline is to provide 6 months to establish consensus and 12 months for deployment. The author has left the motivation and rationale sections blank, urging whoever champions this proposal to complete them.
Updated on: 2023-08-01T20:46:29.371616+00:00