{"type":"rich","version":"1.0","title":"James O'Beirne [ARCHIVE] wrote","author_name":"James O'Beirne [ARCHIVE] (npub1dp…ymz3t)","author_url":"https://yabu.me/npub1dpdfw74plzm03mzglkdegp3hqn6qs9yffqefa5kh98mru49nrg7szymz3t","provider_name":"njump","provider_url":"https://yabu.me","html":"📅 Original date posted:2022-02-17\n📝 Original message:\u003e Is it really true that miners do/should care about that?\n\nDe facto, any miner running an unmodified version of bitcoind doesn't\ncare about anything aside from ancestor fee rate, given that the\nBlockAssembler as-written orders transactions for inclusion by\ndescending ancestor fee-rate and then greedily adds them to the block\ntemplate. [0]\n\nIf anyone has any indication that there are miners running forks of\nbitcoind that change this behavior, I'd be curious to know it.\n\nAlong the lines of what AJ wrote, optimal transaction selection is\nNP-hard (knapsack problem). Any time that a miner spends deciding how\nto assemble the next block is time not spent grinding on the nonce, and\nso I'm skeptical that miners in practice are currently doing anything\nthat isn't fast and simple like the default implementation: sorting\nfee-rate in descending order and then greedily packing.\n\nBut it would be interesting to hear evidence to the contrary.\n\n---\n\nYou can make the argument that transaction selection is just a function\nof mempool contents, and so mempool maintenance criteria might be the\nthing to look at. Mempool acceptance is gated based on a minimum\nfeerate[1].  Mempool eviction (when running low on space) happens on\nthe basis of max(self_feerate, descendant_feerate) [2]. So even in the\nmempool we're still talking in terms of fee rates, not absolute fees.\n\nThat presents us with the \"is/ought\" problem: just because the mempool\n*is* currently gating only on fee rate doesn't mean that's optimal. But\nif the whole point of the mempool is to hold transactions that will be\nmined, and if there's good reason that txns are chosen for mining based\non fee rate (it's quick and good enough), then it seems like fee rate\nis the approximation that should ultimately prevail for txn\nreplacement.\n\n\n[0]:\nhttps://github.com/bitcoin/bitcoin/blob/master/src/node/miner.cpp#L310-L320\n[1]:\nhttps://github.com/bitcoin/bitcoin/blob/master/src/txmempool.cpp#L1106\n[2]:\nhttps://github.com/bitcoin/bitcoin/blob/master/src/txmempool.cpp#L1138-L1144\n-------------- next part --------------\nAn HTML attachment was scrubbed...\nURL: \u003chttp://lists.linuxfoundation.org/pipermail/bitcoin-dev/attachments/20220217/178b279c/attachment.html\u003e"}