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diff --git a/test/functional/dbcrash.py b/test/functional/dbcrash.py
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+#!/usr/bin/env python3
+# Copyright (c) 2017 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 recovery from a crash during chainstate writing."""
+
+from test_framework.test_framework import BitcoinTestFramework
+from test_framework.util import *
+from test_framework.script import *
+from test_framework.mininode import *
+import random
+try:
+ import http.client as httplib
+except ImportError:
+ import httplib
+import errno
+
+'''
+Test structure:
+
+- 4 nodes
+ * node0, node1, and node2 will have different dbcrash ratios, and different
+ dbcache sizes
+ * node3 will be a regular node, with no crashing.
+ * The nodes will not connect to each other.
+
+- use default test framework starting chain. initialize starting_tip_height to
+ tip height.
+
+- Main loop:
+ * generate lots of transactions on node3, enough to fill up a block.
+ * uniformly randomly pick a tip height from starting_tip_height to
+ tip_height; with probability 1/(height_difference+4), invalidate this block.
+ * mine enough blocks to overtake tip_height at start of loop.
+ * for each node in [node0,node1,node2]:
+ - for each mined block:
+ * submit block to node
+ * if node crashed on/after submitting:
+ - restart until recovery succeeds
+ - check that utxo matches node3 using gettxoutsetinfo
+'''
+
+class ChainstateWriteCrashTest(BitcoinTestFramework):
+
+ def __init__(self):
+ super().__init__()
+ self.num_nodes = 4
+ self.setup_clean_chain = False
+
+ # Set -maxmempool=0 to turn off mempool memory sharing with dbcache
+ # Set -rpcservertimeout=900 to reduce socket disconnects in this
+ # long-running test
+ self.base_args = ["-limitdescendantsize=0", "-maxmempool=0", "-rpcservertimeout=900"]
+
+ # Set different crash ratios and cache sizes. Note that not all of
+ # -dbcache goes to pcoinsTip.
+ self.node0_args = ["-dbcrashratio=8", "-dbcache=4", "-dbbatchsize=200000"] + self.base_args
+ self.node1_args = ["-dbcrashratio=16", "-dbcache=8", "-dbbatchsize=200000"] + self.base_args
+ self.node2_args = ["-dbcrashratio=24", "-dbcache=16", "-dbbatchsize=200000"] + self.base_args
+
+ # Node3 is a normal node with default args, except will mine full blocks
+ self.node3_args = ["-blockmaxweight=4000000"]
+ self.extra_args = [self.node0_args, self.node1_args, self.node2_args, self.node3_args]
+
+ # We'll track some test coverage statistics
+ self.restart_counts = [0, 0, 0] # Track the restarts for nodes 0-2
+ self.crashed_on_restart = 0 # Track count of crashes during recovery
+
+ def setup_network(self):
+ self.setup_nodes()
+ # Leave them unconnected, we'll use submitblock directly in this test
+
+ # Starts up a given node id, waits for the tip to reach the given block
+ # hash, and calculates the utxo hash. Exceptions on startup should
+ # indicate node crash (due to -dbcrashratio), in which case we try again.
+ # Give up after 60 seconds.
+ # Returns the utxo hash of the given node.
+ def restart_node(self, node_index, expected_tip):
+ time_start = time.time()
+ while time.time() - time_start < 60:
+ try:
+ # Any of these RPC calls could throw due to node crash
+ self.nodes[node_index] = self.start_node(node_index, self.options.tmpdir, self.extra_args[node_index])
+ self.nodes[node_index].waitforblock(expected_tip)
+ utxo_hash = self.nodes[node_index].gettxoutsetinfo()['hash_serialized_2']
+ return utxo_hash
+ except:
+ # An exception here should mean the node is about to crash.
+ # If bitcoind exits, then try again. wait_for_node_exit()
+ # should raise an exception if bitcoind doesn't exit.
+ wait_for_node_exit(node_index, timeout=10)
+ self.crashed_on_restart += 1
+ time.sleep(1)
+
+ # If we got here, bitcoind isn't coming back up on restart. Could be a
+ # bug in bitcoind, or we've gotten unlucky with our dbcrash ratio --
+ # perhaps we generated a test case that blew up our cache?
+ # TODO: If this happens a lot, we should try to restart without -dbcrashratio
+ # and make sure that recovery happens.
+ raise AssertionError("Unable to successfully restart node %d in allotted time", node_index)
+
+ # Try submitting a block to the given node.
+ # Catch any exceptions that indicate the node has crashed.
+ # Returns true if the block was submitted successfully; false otherwise.
+ def submit_block_catch_error(self, node_index, block):
+ try:
+ self.nodes[node_index].submitblock(block)
+ return True
+ except (httplib.CannotSendRequest, httplib.RemoteDisconnected) as e:
+ self.log.debug("node %d submitblock raised exception: %s", node_index, e)
+ return False
+ except OSError as e:
+ self.log.debug("node %d submitblock raised OSError exception: errno=%s", node_index, e.errno)
+ if e.errno in [errno.EPIPE, errno.ECONNREFUSED, errno.ECONNRESET]:
+ # The node has likely crashed
+ return False
+ else:
+ # Unexpected exception, raise
+ raise
+
+ # Use submitblock to sync node3's chain with the other nodes
+ # If submitblock fails, restart the node and get the new utxo hash.
+ def sync_node3blocks(self, block_hashes):
+ # If any nodes crash while updating, we'll compare utxo hashes to
+ # ensure recovery was successful.
+ node3_utxo_hash = self.nodes[3].gettxoutsetinfo()['hash_serialized_2']
+
+ # Retrieve all the blocks from node3
+ blocks = []
+ for block_hash in block_hashes:
+ blocks.append([block_hash, self.nodes[3].getblock(block_hash, 0)])
+
+ # Deliver each block to each other node
+ for i in range(3):
+ nodei_utxo_hash = None
+ self.log.debug("Syncing blocks to node %d", i)
+ for (block_hash, block) in blocks:
+ # Get the block from node3, and submit to node_i
+ self.log.debug("submitting block %s", block_hash)
+ if not self.submit_block_catch_error(i, block):
+ # TODO: more carefully check that the crash is due to -dbcrashratio
+ # (change the exit code perhaps, and check that here?)
+ wait_for_node_exit(i, timeout=30)
+ self.log.debug("Restarting node %d after block hash %s", i, block_hash)
+ nodei_utxo_hash = self.restart_node(i, block_hash)
+ assert nodei_utxo_hash is not None
+ self.restart_counts[i] += 1
+ else:
+ # Clear it out after successful submitblock calls -- the cached
+ # utxo hash will no longer be correct
+ nodei_utxo_hash = None
+
+ # Check that the utxo hash matches node3's utxo set
+ # NOTE: we only check the utxo set if we had to restart the node
+ # after the last block submitted:
+ # - checking the utxo hash causes a cache flush, which we don't
+ # want to do every time; so
+ # - we only update the utxo cache after a node restart, since flushing
+ # the cache is a no-op at that point
+ if nodei_utxo_hash is not None:
+ self.log.debug("Checking txoutsetinfo matches for node %d", i)
+ assert_equal(nodei_utxo_hash, node3_utxo_hash)
+
+ # Verify that the utxo hash of each node matches node3.
+ # Restart any nodes that crash while querying.
+ def verify_utxo_hash(self):
+ node3_utxo_hash = self.nodes[3].gettxoutsetinfo()['hash_serialized_2']
+ self.log.info("Verifying utxo hash matches for all nodes")
+
+ for i in range(3):
+ try:
+ nodei_utxo_hash = self.nodes[i].gettxoutsetinfo()['hash_serialized_2']
+ except OSError:
+ # probably a crash on db flushing
+ nodei_utxo_hash = self.restart_node(i, self.nodes[3].getbestblockhash())
+ assert_equal(nodei_utxo_hash, node3_utxo_hash)
+
+
+ def generate_small_transactions(self, node, count, utxo_list):
+ FEE = 1000 # TODO: replace this with node relay fee based calculation
+ num_transactions = 0
+ random.shuffle(utxo_list)
+ while len(utxo_list) >= 2 and num_transactions < count:
+ tx = CTransaction()
+ input_amount = 0
+ for i in range(2):
+ utxo = utxo_list.pop()
+ tx.vin.append(CTxIn(COutPoint(int(utxo['txid'], 16), utxo['vout'])))
+ input_amount += int(utxo['amount']*COIN)
+ output_amount = (input_amount - FEE)//3
+
+ if output_amount <= 0:
+ # Sanity check -- if we chose inputs that are too small, skip
+ continue
+
+ for i in range(3):
+ tx.vout.append(CTxOut(output_amount, hex_str_to_bytes(utxo['scriptPubKey'])))
+
+ # Sign and send the transaction to get into the mempool
+ tx_signed_hex = node.signrawtransaction(ToHex(tx))['hex']
+ node.sendrawtransaction(tx_signed_hex)
+ num_transactions += 1
+
+ def run_test(self):
+
+ # Start by creating a lot of utxos on node3
+ initial_height = self.nodes[3].getblockcount()
+ utxo_list = create_confirmed_utxos(self.nodes[3].getnetworkinfo()['relayfee'], self.nodes[3], 5000)
+ self.log.info("Prepped %d utxo entries", len(utxo_list))
+
+ # Sync these blocks with the other nodes
+ block_hashes_to_sync = []
+ for height in range(initial_height+1, self.nodes[3].getblockcount()+1):
+ block_hashes_to_sync.append(self.nodes[3].getblockhash(height))
+
+ self.log.debug("Syncing %d blocks with other nodes", len(block_hashes_to_sync))
+ # Syncing the blocks could cause nodes to crash, so the test begins here.
+ self.sync_node3blocks(block_hashes_to_sync)
+
+ starting_tip_height = self.nodes[3].getblockcount()
+
+ # Main test loop:
+ # each time through the loop, generate a bunch of transactions,
+ # and then either mine a single new block on the tip, or some-sized reorg.
+ for i in range(40):
+ self.log.info("Iteration %d, generating 2500 transactions %s", i, self.restart_counts)
+ # Generate a bunch of small-ish transactions
+ self.generate_small_transactions(self.nodes[3], 2500, utxo_list)
+ # Pick a random block between current tip, and starting tip
+ current_height = self.nodes[3].getblockcount()
+ random_height = random.randint(starting_tip_height, current_height)
+ self.log.debug("At height %d, considering height %d", current_height, random_height)
+ if random_height > starting_tip_height:
+ # Randomly reorg from this point with some probability (1/4 for
+ # tip, 1/5 for tip-1, ...)
+ if random.random() < 1.0/(current_height + 4 - random_height):
+ self.log.debug("Invalidating block at height %d", random_height)
+ self.nodes[3].invalidateblock(self.nodes[3].getblockhash(random_height))
+
+ # Now generate new blocks until we pass the old tip height
+ self.log.debug("Mining longer tip")
+ block_hashes = self.nodes[3].generate(current_height+1-self.nodes[3].getblockcount())
+ self.log.debug("Syncing %d new blocks...", len(block_hashes))
+ self.sync_node3blocks(block_hashes)
+ utxo_list = self.nodes[3].listunspent()
+ self.log.debug("Node3 utxo count: %d", len(utxo_list))
+
+ # Check that the utxo hashes agree with node3
+ # Useful side effect: each utxo cache gets flushed here, so that we
+ # won't get crashes on shutdown at the end of the test.
+ self.verify_utxo_hash()
+
+ # Check the test coverage
+ self.log.info("Restarted nodes: %s; crashes on restart: %d", self.restart_counts, self.crashed_on_restart)
+
+ # If no nodes were restarted, we didn't test anything.
+ assert self.restart_counts != [0, 0, 0]
+
+ # Make sure we tested the case of crash-during-recovery.
+ assert self.crashed_on_restart > 0
+
+ # Warn if any of the nodes escaped restart.
+ for i in range(3):
+ if self.restart_counts[i] == 0:
+ self.log.warn("Node %d never crashed during utxo flush!", i)
+
+if __name__ == "__main__":
+ ChainstateWriteCrashTest().main()