rich1.0npub1g6vxlp4e0nyhs2dqxxcryztyf5f5hyuaq93nw4r87zcnv0sdsa0qqsl5wdhttps://nostr.ae/npub1g6vxlp4e0nyhs2dqxxcryztyf5f5hyuaq93nw4r87zcnv0sdsa0qqsl5wdnjumphttps://nostr.ae📅 Original date posted:2015-07-10 📝 Original message:On Fri, Jul 10, 2015 at 5:09 PM, Richard Moore <me at ricmoo.com> wrote: > I was also wondering, with CPFP, should the transaction fee be based on > total transactions size, or the sum of each transaction’s required fee? For > example, a third transaction C whose unconfirmed utxo from transaction B > has an unconfirmed utxo in transaction A (all of A’s inputs are confirmed), > with each A, B and C being ~300bytes, should C’s transaction fee be 0.0001 > btc for the ~1kb it is about to commit to the blockchain, or 0.0003 btc for > the 3 transactions it is going to commit. > It should be whatever gives the highest fee. In effect, child pays for parent creates compound transactions. A: 250 bytes, 0 fee B: 300 bytes: 0.0005 fee C: 400 bytes: 0.0001 fee There are 3 combinations to consider A: 0 fee for 250 bytes = 0 per byte A&B: 0.0005 fee for 550 bytes = 0.91 uBTC per byte A&B&C: 0.0006 fee for 950 bytes = 0.63uBTC per byte This means that the A&B combination has the best fee per byte value. A&B should be added to the memory pool (if 0.91 uBTC per byte is above the threshold). Once A&B are added, then C can be reconsidered on its own. C: 0.0001 for 400 bytes = 0.25 BTC per byte If that is above the threshold, then C should be added. In practice, it isn't possible to check every combination. If there are N transactions, then checking all triple combinations costs around N cubed. A 2 pass system could get a reasonably efficient result. B is 0.0005 fee for 300 bytes = 1.67 uBTC per byte and is assumed to be a high value transaction. The algorithm would be Pass 1: Process all transactions in order of BTC per byte, until block is full If the transaction's parents are either already in the pool or a previous block, add the transaction. Pass 1: Process all non-included transactions in order of BTC per byte, until block is full If the transaction's parents are either already in the pool or a previous block, add the transaction. Otherwise, consider the transaction plus all non-included ancestors as a single transaction If this combined transaction has a higher BTC per byte than the lowest transaction(s), add the combined transaction drop the other transaction(s) -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.linuxfoundation.org/pipermail/bitcoin-dev/attachments/20150710/68d6acca/attachment.html>