1 #!/usr/bin/env python3
2 # Copyright (c) 2014-present The Bitcoin Core developers
3 # Distributed under the MIT software license, see the accompanying
4 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
5 """Test mempool limiting together/eviction with the wallet."""
6 7 from decimal import Decimal
8 9 from test_framework.mempool_util import (
10 fill_mempool,
11 )
12 from test_framework.p2p import P2PTxInvStore
13 from test_framework.test_framework import BitcoinTestFramework
14 from test_framework.util import (
15 assert_equal,
16 assert_fee_amount,
17 assert_greater_than,
18 assert_raises_rpc_error,
19 )
20 from test_framework.wallet import (
21 COIN,
22 DEFAULT_FEE,
23 MiniWallet,
24 )
25 26 27 class MempoolLimitTest(BitcoinTestFramework):
28 def set_test_params(self):
29 self.setup_clean_chain = True
30 self.num_nodes = 1
31 self.extra_args = [[
32 "-maxmempool=5",
33 ]]
34 35 def test_mid_package_eviction_success(self):
36 node = self.nodes[0]
37 self.log.info("Check a package where each parent passes the current mempoolminfee but a parent could be evicted before getting child's descendant feerate")
38 39 # Clear mempool so it can be filled with minrelay txns
40 self.restart_node(0, extra_args=self.extra_args[0] + ["-persistmempool=0"])
41 assert_equal(node.getrawmempool(), [])
42 43 # Restarting the node resets mempool minimum feerate
44 assert_equal(node.getmempoolinfo()['minrelaytxfee'], node.getmempoolinfo()["mempoolminfee"])
45 46 fill_mempool(self, node)
47 current_info = node.getmempoolinfo()
48 mempoolmin_feerate = current_info["mempoolminfee"]
49 50 mempool_txids = node.getrawmempool()
51 mempool_entries = [node.getmempoolentry(entry) for entry in mempool_txids]
52 fees_btc_per_kvb = [entry["fees"]["base"] / (Decimal(entry["vsize"]) / 1000) for entry in mempool_entries]
53 mempool_entry_minrate = min(fees_btc_per_kvb)
54 mempool_entry_minrate = mempool_entry_minrate.quantize(Decimal("0.00000000"))
55 56 # There is a gap, our parents will be minrate, with child bringing up descendant fee sufficiently to avoid
57 # eviction even though parents cause eviction on their own
58 assert_greater_than(mempool_entry_minrate, mempoolmin_feerate)
59 60 package_hex = []
61 # UTXOs to be spent by the ultimate child transaction
62 parent_utxos = []
63 64 # Series of parents that don't need CPFP and are submitted individually. Each one is large
65 # which means in aggregate they could trigger eviction, but child submission should result
66 # in them not being evicted
67 parent_vsize = 25000
68 num_big_parents = 3
69 # Need to be large enough to trigger eviction
70 # (note that the mempool usage of a tx is about three times its vsize)
71 assert_greater_than(parent_vsize * num_big_parents * 3, current_info["maxmempool"] - current_info["bytes"])
72 73 big_parent_txids = []
74 big_parent_wtxids = []
75 for i in range(num_big_parents):
76 # Last parent is higher feerate causing other parents to possibly
77 # be evicted if trimming was allowed, which would cause the package to end up failing
78 parent_feerate = mempoolmin_feerate + Decimal("0.00000001") if i == num_big_parents - 1 else mempoolmin_feerate
79 parent = self.wallet.create_self_transfer(fee_rate=parent_feerate, target_vsize=parent_vsize, confirmed_only=True)
80 parent_utxos.append(parent["new_utxo"])
81 package_hex.append(parent["hex"])
82 big_parent_txids.append(parent["txid"])
83 big_parent_wtxids.append(parent["wtxid"])
84 # There is room for each of these transactions independently
85 assert node.testmempoolaccept([parent["hex"]])[0]["allowed"]
86 87 # Create a child spending everything with an insane fee, bumping the package above mempool_entry_minrate
88 child = self.wallet.create_self_transfer_multi(utxos_to_spend=parent_utxos, fee_per_output=10000000)
89 package_hex.append(child["hex"])
90 91 # Package should be submitted, temporarily exceeding maxmempool, but not evicted.
92 package_res = None
93 with node.assert_debug_log(expected_msgs=["rolling minimum fee bumped"]):
94 package_res = node.submitpackage(package=package_hex, maxfeerate=0)
95 96 assert_equal(package_res["package_msg"], "success")
97 98 # Ensure that intra-package trimming is not happening.
99 # Each transaction separately satisfies the current
100 # minfee and shouldn't need package evaluation to
101 # be included. If trimming of a parent were to happen,
102 # package evaluation would happen to reintrodce the evicted
103 # parent.
104 assert_equal(len(package_res["tx-results"]), len(big_parent_wtxids) + 1)
105 for wtxid in big_parent_wtxids + [child["wtxid"]]:
106 assert_equal(len(package_res["tx-results"][wtxid]["fees"]["effective-includes"]), 1)
107 108 # Maximum size must never be exceeded.
109 assert_greater_than(node.getmempoolinfo()["maxmempool"], node.getmempoolinfo()["bytes"])
110 111 # Package found in mempool still
112 resulting_mempool_txids = node.getrawmempool()
113 assert child["txid"] in resulting_mempool_txids
114 for txid in big_parent_txids:
115 assert txid in resulting_mempool_txids
116 117 # Check every evicted tx was higher feerate than parents which evicted it
118 eviction_set = set(mempool_txids) - set(resulting_mempool_txids) - set(big_parent_txids)
119 parent_entries = [node.getmempoolentry(entry) for entry in big_parent_txids]
120 max_parent_feerate = max([entry["fees"]["modified"] / (Decimal(entry["vsize"]) / 1000) for entry in parent_entries])
121 for eviction in eviction_set:
122 assert eviction in mempool_txids
123 for txid, entry in zip(mempool_txids, mempool_entries):
124 if txid == eviction:
125 evicted_feerate_btc_per_kvb = entry["fees"]["modified"] / (Decimal(entry["vsize"]) / 1000)
126 assert_greater_than(evicted_feerate_btc_per_kvb, max_parent_feerate)
127 128 def test_mid_package_replacement(self):
129 node = self.nodes[0]
130 self.log.info("Check a package where an early tx depends on a later-replaced mempool tx")
131 132 self.restart_node(0, extra_args=self.extra_args[0])
133 134 # Restarting the node resets mempool minimum feerate
135 assert_equal(node.getmempoolinfo()['minrelaytxfee'], node.getmempoolinfo()["mempoolminfee"])
136 137 fill_mempool(self, node)
138 current_info = node.getmempoolinfo()
139 mempoolmin_feerate = current_info["mempoolminfee"]
140 141 # Mempool transaction is replaced by a package transaction.
142 double_spent_utxo = self.wallet.get_utxo(confirmed_only=True)
143 replaced_tx = self.wallet.send_self_transfer(
144 from_node=node,
145 utxo_to_spend=double_spent_utxo,
146 fee_rate=mempoolmin_feerate,
147 confirmed_only=True
148 )
149 # Already in mempool when package is submitted.
150 assert replaced_tx["txid"] in node.getrawmempool()
151 152 # This parent spends the above mempool transaction that exists when its inputs are first
153 # looked up, but will disappear if the replacement occurs. It is rejected for being too low fee (but eligible for
154 # reconsideration), and its inputs are cached. When the mempool transaction is replaced, its
155 # coin is no longer available, but the cache could still contain the tx.
156 cpfp_parent = self.wallet.create_self_transfer(
157 utxo_to_spend=replaced_tx["new_utxo"],
158 fee_rate=mempoolmin_feerate - Decimal('0.000001'),
159 confirmed_only=True)
160 161 self.wallet.rescan_utxos()
162 163 # Parent that replaces the parent of cpfp_parent.
164 replacement_tx = self.wallet.create_self_transfer(
165 utxo_to_spend=double_spent_utxo,
166 fee_rate=10*mempoolmin_feerate,
167 confirmed_only=True
168 )
169 parent_utxos = [cpfp_parent["new_utxo"], replacement_tx["new_utxo"]]
170 171 # Create a child spending everything, CPFPing the low-feerate parent.
172 approx_child_vsize = self.wallet.create_self_transfer_multi(utxos_to_spend=parent_utxos)["tx"].get_vsize()
173 cpfp_fee = (2 * mempoolmin_feerate / 1000) * (cpfp_parent["tx"].get_vsize() + approx_child_vsize) - cpfp_parent["fee"]
174 child = self.wallet.create_self_transfer_multi(utxos_to_spend=parent_utxos, fee_per_output=int(cpfp_fee * COIN))
175 # It's very important that the cpfp_parent is before replacement_tx so that its input (from
176 # replaced_tx) is first looked up *before* replacement_tx is submitted.
177 package_hex = [cpfp_parent["hex"], replacement_tx["hex"], child["hex"]]
178 179 # Package should be submitted, temporarily exceeding maxmempool, and then evicted.
180 res = node.submitpackage(package_hex)
181 assert_equal(res["package_msg"], "transaction failed")
182 assert "bad-txns-inputs-missingorspent" in [tx_res["error"] for _, tx_res in res["tx-results"].items() if "error" in tx_res]
183 184 # Maximum size must never be exceeded.
185 assert_greater_than(node.getmempoolinfo()["maxmempool"], node.getmempoolinfo()["bytes"])
186 187 resulting_mempool_txids = node.getrawmempool()
188 # The replacement should be successful.
189 assert replacement_tx["txid"] in resulting_mempool_txids
190 # The replaced tx and all of its descendants must not be in mempool.
191 assert replaced_tx["txid"] not in resulting_mempool_txids
192 assert cpfp_parent["txid"] not in resulting_mempool_txids
193 assert child["txid"] not in resulting_mempool_txids
194 195 196 def run_test(self):
197 node = self.nodes[0]
198 self.wallet = MiniWallet(node)
199 miniwallet = self.wallet
200 201 # Generate coins needed to create transactions in the subtests (excluding coins used in fill_mempool).
202 self.generate(miniwallet, 20)
203 204 relayfee = node.getnetworkinfo()['relayfee']
205 self.log.info('Check that mempoolminfee is minrelaytxfee')
206 assert_equal(node.getmempoolinfo()['minrelaytxfee'], node.getmempoolinfo()["mempoolminfee"])
207 208 fill_mempool(self, node)
209 210 # 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
211 self.log.info('Create a mempool tx that will not pass mempoolminfee')
212 assert_raises_rpc_error(-26, "mempool min fee not met", miniwallet.send_self_transfer, from_node=node, fee_rate=relayfee)
213 214 self.log.info("Check that submitpackage allows cpfp of a parent below mempool min feerate")
215 node = self.nodes[0]
216 peer = node.add_p2p_connection(P2PTxInvStore())
217 218 # Package with 2 parents and 1 child. One parent has a high feerate due to modified fees,
219 # another is below the mempool minimum feerate but bumped by the child.
220 tx_poor = miniwallet.create_self_transfer(fee_rate=relayfee)
221 tx_rich = miniwallet.create_self_transfer(fee=0, fee_rate=0)
222 node.prioritisetransaction(tx_rich["txid"], 0, int(DEFAULT_FEE * COIN))
223 package_txns = [tx_rich, tx_poor]
224 coins = [tx["new_utxo"] for tx in package_txns]
225 tx_child = miniwallet.create_self_transfer_multi(utxos_to_spend=coins, fee_per_output=10000) #DEFAULT_FEE
226 package_txns.append(tx_child)
227 228 submitpackage_result = node.submitpackage([tx["hex"] for tx in package_txns])
229 assert_equal(submitpackage_result["package_msg"], "success")
230 231 rich_parent_result = submitpackage_result["tx-results"][tx_rich["wtxid"]]
232 poor_parent_result = submitpackage_result["tx-results"][tx_poor["wtxid"]]
233 child_result = submitpackage_result["tx-results"][tx_child["tx"].wtxid_hex]
234 assert_fee_amount(poor_parent_result["fees"]["base"], tx_poor["tx"].get_vsize(), relayfee)
235 assert_equal(rich_parent_result["fees"]["base"], 0)
236 assert_equal(child_result["fees"]["base"], DEFAULT_FEE)
237 # The "rich" parent does not require CPFP so its effective feerate is just its individual feerate.
238 assert_fee_amount(DEFAULT_FEE, tx_rich["tx"].get_vsize(), rich_parent_result["fees"]["effective-feerate"])
239 assert_equal(rich_parent_result["fees"]["effective-includes"], [tx_rich["wtxid"]])
240 # The "poor" parent and child's effective feerates are the same, composed of their total
241 # fees divided by their combined vsize.
242 package_fees = poor_parent_result["fees"]["base"] + child_result["fees"]["base"]
243 package_vsize = tx_poor["tx"].get_vsize() + tx_child["tx"].get_vsize()
244 assert_fee_amount(package_fees, package_vsize, poor_parent_result["fees"]["effective-feerate"])
245 assert_fee_amount(package_fees, package_vsize, child_result["fees"]["effective-feerate"])
246 assert_equal([tx_poor["wtxid"], tx_child["tx"].wtxid_hex], poor_parent_result["fees"]["effective-includes"])
247 assert_equal([tx_poor["wtxid"], tx_child["tx"].wtxid_hex], child_result["fees"]["effective-includes"])
248 249 # The node will broadcast each transaction, still abiding by its peer's fee filter
250 peer.wait_for_broadcast([tx["tx"].wtxid_hex for tx in package_txns])
251 252 self.log.info("Check a package that passes mempoolminfee but is evicted immediately after submission")
253 mempoolmin_feerate = node.getmempoolinfo()["mempoolminfee"]
254 current_mempool = node.getrawmempool(verbose=False)
255 worst_feerate_btcvb = Decimal("21000000")
256 for txid in current_mempool:
257 entry = node.getmempoolentry(txid)
258 worst_feerate_btcvb = min(worst_feerate_btcvb, entry["fees"]["descendant"] / entry["descendantsize"])
259 # Needs to be large enough to trigger eviction
260 # (note that the mempool usage of a tx is about three times its vsize)
261 target_vsize_each = 50000
262 assert_greater_than(target_vsize_each * 2 * 3, node.getmempoolinfo()["maxmempool"] - node.getmempoolinfo()["bytes"])
263 # Should be a true CPFP: parent's feerate is just below mempool min feerate
264 parent_feerate = mempoolmin_feerate - Decimal("0.0000001") # 0.01 sats/vbyte below min feerate
265 # Parent + child is above mempool minimum feerate
266 child_feerate = (worst_feerate_btcvb * 1000) - Decimal("0.0000001") # 0.01 sats/vbyte below worst feerate
267 # However, when eviction is triggered, these transactions should be at the bottom.
268 # This assertion assumes parent and child are the same size.
269 miniwallet.rescan_utxos()
270 tx_parent_just_below = miniwallet.create_self_transfer(fee_rate=parent_feerate, target_vsize=target_vsize_each)
271 tx_child_just_above = miniwallet.create_self_transfer(utxo_to_spend=tx_parent_just_below["new_utxo"], fee_rate=child_feerate, target_vsize=target_vsize_each)
272 # This package ranks below the lowest descendant package in the mempool
273 package_fee = tx_parent_just_below["fee"] + tx_child_just_above["fee"]
274 package_vsize = tx_parent_just_below["tx"].get_vsize() + tx_child_just_above["tx"].get_vsize()
275 assert_greater_than(worst_feerate_btcvb, package_fee / package_vsize)
276 assert_greater_than(mempoolmin_feerate, tx_parent_just_below["fee"] / (tx_parent_just_below["tx"].get_vsize()))
277 assert_greater_than(package_fee / package_vsize, mempoolmin_feerate / 1000)
278 res = node.submitpackage([tx_parent_just_below["hex"], tx_child_just_above["hex"]])
279 for wtxid in [tx_parent_just_below["wtxid"], tx_child_just_above["wtxid"]]:
280 assert_equal(res["tx-results"][wtxid]["error"], "mempool full")
281 282 self.log.info('Test passing a value below the minimum (5 MB) to -maxmempool throws an error')
283 self.stop_node(0)
284 self.nodes[0].assert_start_raises_init_error(["-maxmempool=4"], "Error: -maxmempool must be at least 5 MB")
285 286 self.test_mid_package_eviction_success()
287 self.test_mid_package_replacement()
288 289 290 if __name__ == '__main__':
291 MempoolLimitTest(__file__).main()
292