#!/usr/bin/env python3 # Copyright (c) 2014-2022 The Bitcoin Core developers # Distributed under the MIT software license, see the accompanying # file COPYING or http://www.opensource.org/licenses/mit-license.php. """Test mempool limiting together/eviction with the wallet.""" from decimal import Decimal from test_framework.blocktools import COINBASE_MATURITY from test_framework.p2p import P2PTxInvStore from test_framework.test_framework import BitcoinTestFramework from test_framework.util import ( assert_equal, assert_fee_amount, assert_greater_than, assert_raises_rpc_error, create_lots_of_big_transactions, gen_return_txouts, ) from test_framework.wallet import ( COIN, DEFAULT_FEE, MiniWallet, ) class MempoolLimitTest(BitcoinTestFramework): def set_test_params(self): self.setup_clean_chain = True self.num_nodes = 1 self.extra_args = [[ "-datacarriersize=100000", "-maxmempool=5", ]] self.supports_cli = False def run_test(self): txouts = gen_return_txouts() node = self.nodes[0] miniwallet = MiniWallet(node) relayfee = node.getnetworkinfo()['relayfee'] self.log.info('Check that mempoolminfee is minrelaytxfee') assert_equal(node.getmempoolinfo()['minrelaytxfee'], Decimal('0.00001000')) assert_equal(node.getmempoolinfo()['mempoolminfee'], Decimal('0.00001000')) tx_batch_size = 1 num_of_batches = 75 # Generate UTXOs to flood the mempool # 1 to create a tx initially that will be evicted from the mempool later # 3 batches of multiple transactions with a fee rate much higher than the previous UTXO # And 1 more to verify that this tx does not get added to the mempool with a fee rate less than the mempoolminfee # And 2 more for the package cpfp test self.generate(miniwallet, 1 + (num_of_batches * tx_batch_size) + 1 + 2) # Mine 99 blocks so that the UTXOs are allowed to be spent self.generate(node, COINBASE_MATURITY - 1) self.log.info('Create a mempool tx that will be evicted') tx_to_be_evicted_id = miniwallet.send_self_transfer(from_node=node, fee_rate=relayfee)["txid"] # Increase the tx fee rate to give the subsequent transactions a higher priority in the mempool # The tx has an approx. vsize of 65k, i.e. multiplying the previous fee rate (in sats/kvB) # by 130 should result in a fee that corresponds to 2x of that fee rate base_fee = relayfee * 130 self.log.info("Fill up the mempool with txs with higher fee rate") for batch_of_txid in range(num_of_batches): fee = (batch_of_txid + 1) * base_fee create_lots_of_big_transactions(miniwallet, node, fee, tx_batch_size, txouts) self.log.info('The tx should be evicted by now') # The number of transactions created should be greater than the ones present in the mempool assert_greater_than(tx_batch_size * num_of_batches, len(node.getrawmempool())) # Initial tx created should not be present in the mempool anymore as it had a lower fee rate assert tx_to_be_evicted_id not in node.getrawmempool() self.log.info('Check that mempoolminfee is larger than minrelaytxfee') assert_equal(node.getmempoolinfo()['minrelaytxfee'], Decimal('0.00001000')) assert_greater_than(node.getmempoolinfo()['mempoolminfee'], Decimal('0.00001000')) # Deliberately try to create a tx with a fee less than the minimum mempool fee to assert that it does not get added to the mempool self.log.info('Create a mempool tx that will not pass mempoolminfee') assert_raises_rpc_error(-26, "mempool min fee not met", miniwallet.send_self_transfer, from_node=node, fee_rate=relayfee) self.log.info("Check that submitpackage allows cpfp of a parent below mempool min feerate") node = self.nodes[0] peer = node.add_p2p_connection(P2PTxInvStore()) # Package with 2 parents and 1 child. One parent has a high feerate due to modified fees, # another is below the mempool minimum feerate but bumped by the child. tx_poor = miniwallet.create_self_transfer(fee_rate=relayfee) tx_rich = miniwallet.create_self_transfer(fee=0, fee_rate=0) node.prioritisetransaction(tx_rich["txid"], 0, int(DEFAULT_FEE * COIN)) package_txns = [tx_rich, tx_poor] coins = [tx["new_utxo"] for tx in package_txns] tx_child = miniwallet.create_self_transfer_multi(utxos_to_spend=coins, fee_per_output=10000) #DEFAULT_FEE package_txns.append(tx_child) submitpackage_result = node.submitpackage([tx["hex"] for tx in package_txns]) rich_parent_result = submitpackage_result["tx-results"][tx_rich["wtxid"]] poor_parent_result = submitpackage_result["tx-results"][tx_poor["wtxid"]] child_result = submitpackage_result["tx-results"][tx_child["tx"].getwtxid()] assert_fee_amount(poor_parent_result["fees"]["base"], tx_poor["tx"].get_vsize(), relayfee) assert_equal(rich_parent_result["fees"]["base"], 0) assert_equal(child_result["fees"]["base"], DEFAULT_FEE) # The "rich" parent does not require CPFP so its effective feerate is just its individual feerate. assert_fee_amount(DEFAULT_FEE, tx_rich["tx"].get_vsize(), rich_parent_result["fees"]["effective-feerate"]) assert_equal(rich_parent_result["fees"]["effective-includes"], [tx_rich["wtxid"]]) # The "poor" parent and child's effective feerates are the same, composed of their total # fees divided by their combined vsize. package_fees = poor_parent_result["fees"]["base"] + child_result["fees"]["base"] package_vsize = tx_poor["tx"].get_vsize() + tx_child["tx"].get_vsize() assert_fee_amount(package_fees, package_vsize, poor_parent_result["fees"]["effective-feerate"]) assert_fee_amount(package_fees, package_vsize, child_result["fees"]["effective-feerate"]) assert_equal([tx_poor["wtxid"], tx_child["tx"].getwtxid()], poor_parent_result["fees"]["effective-includes"]) assert_equal([tx_poor["wtxid"], tx_child["tx"].getwtxid()], child_result["fees"]["effective-includes"]) # The node will broadcast each transaction, still abiding by its peer's fee filter peer.wait_for_broadcast([tx["tx"].getwtxid() for tx in package_txns]) self.log.info("Check a package that passes mempoolminfee but is evicted immediately after submission") mempoolmin_feerate = node.getmempoolinfo()["mempoolminfee"] current_mempool = node.getrawmempool(verbose=False) worst_feerate_btcvb = Decimal("21000000") for txid in current_mempool: entry = node.getmempoolentry(txid) worst_feerate_btcvb = min(worst_feerate_btcvb, entry["fees"]["descendant"] / entry["descendantsize"]) # Needs to be large enough to trigger eviction target_weight_each = 200000 assert_greater_than(target_weight_each * 2, node.getmempoolinfo()["maxmempool"] - node.getmempoolinfo()["bytes"]) # Should be a true CPFP: parent's feerate is just below mempool min feerate parent_fee = (mempoolmin_feerate / 1000) * (target_weight_each // 4) - Decimal("0.00001") # Parent + child is above mempool minimum feerate child_fee = (worst_feerate_btcvb) * (target_weight_each // 4) - Decimal("0.00001") # However, when eviction is triggered, these transactions should be at the bottom. # This assertion assumes parent and child are the same size. miniwallet.rescan_utxos() tx_parent_just_below = miniwallet.create_self_transfer(fee=parent_fee, target_weight=target_weight_each) tx_child_just_above = miniwallet.create_self_transfer(utxo_to_spend=tx_parent_just_below["new_utxo"], fee=child_fee, target_weight=target_weight_each) # This package ranks below the lowest descendant package in the mempool assert_greater_than(worst_feerate_btcvb, (parent_fee + child_fee) / (tx_parent_just_below["tx"].get_vsize() + tx_child_just_above["tx"].get_vsize())) assert_greater_than(mempoolmin_feerate, (parent_fee) / (tx_parent_just_below["tx"].get_vsize())) assert_greater_than((parent_fee + child_fee) / (tx_parent_just_below["tx"].get_vsize() + tx_child_just_above["tx"].get_vsize()), mempoolmin_feerate / 1000) assert_raises_rpc_error(-26, "mempool full", node.submitpackage, [tx_parent_just_below["hex"], tx_child_just_above["hex"]]) self.log.info('Test passing a value below the minimum (5 MB) to -maxmempool throws an error') self.stop_node(0) self.nodes[0].assert_start_raises_init_error(["-maxmempool=4"], "Error: -maxmempool must be at least 5 MB") if __name__ == '__main__': MempoolLimitTest().main()