ClickHouse/tests/integration/test_hedged_requests/test.py

import os
import sys
import time

import pytest

sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))

from helpers.cluster import ClickHouseCluster
from helpers.network import PartitionManager
from helpers.test_tools import TSV

cluster = ClickHouseCluster(__file__)
NODES = {'node_' + str(i): None for i in (1, 2, 3)}

NODES['node'] = None

# Sleep time in milliseconds.
sleep_time = 30000

@pytest.fixture(scope="module")
def started_cluster():
    NODES['node'] = cluster.add_instance(
    'node', stay_alive=True, main_configs=['configs/remote_servers.xml'], user_configs=['configs/users.xml'])

    for name in NODES:
        if name != 'node':
            NODES[name] = cluster.add_instance(name, user_configs=['configs/users1.xml'])

    try:
        cluster.start()

        for node_id, node in list(NODES.items()):
            node.query('''CREATE TABLE test_hedged (id UInt32, date Date) ENGINE =
            MergeTree()  ORDER BY id PARTITION BY toYYYYMM(date)''')

            node.query("INSERT INTO test_hedged select number, toDate(number) from numbers(100);")


        NODES['node'].query('''CREATE TABLE distributed (id UInt32, date Date) ENGINE =
            Distributed('test_cluster', 'default', 'test_hedged')''')

        yield cluster

    finally:
        cluster.shutdown()


config = '''<yandex>
    <profiles>
        <default>
            <sleep_in_send_tables_status_ms>{sleep_in_send_tables_status_ms}</sleep_in_send_tables_status_ms>
            <sleep_in_send_data_ms>{sleep_in_send_data_ms}</sleep_in_send_data_ms>
        </default>
    </profiles>
</yandex>'''


def check_query(expected_replica, receive_timeout=300):
    NODES['node'].restart_clickhouse()
    
    # Without hedged requests select query will last more than 30 seconds,
    # with hedged requests it will last just around 1-2 second

    start = time.time()
    result = NODES['node'].query("SELECT hostName(), id FROM distributed ORDER BY id LIMIT 1 SETTINGS receive_timeout={}".format(receive_timeout));
    query_time = time.time() - start

    assert TSV(result) == TSV(expected_replica + "\t0")

    print("Query time:", query_time)
    assert query_time < 10


def check_settings(node_name, sleep_in_send_tables_status_ms, sleep_in_send_data_ms):
    attempts = 0
    while attempts < 1000:
        setting1 = NODES[node_name].http_query("SELECT value FROM system.settings WHERE name='sleep_in_send_tables_status_ms'")
        setting2 = NODES[node_name].http_query("SELECT value FROM system.settings WHERE name='sleep_in_send_data_ms'")
        if int(setting1) == sleep_in_send_tables_status_ms and int(setting2) == sleep_in_send_data_ms:
            return
        time.sleep(0.1)
        attempts += 1

    assert attempts < 1000


def check_changing_replica_events(expected_count):
    result = NODES['node'].query("SELECT value FROM system.events WHERE event='HedgedRequestsChangeReplica'")

    # If server load is high we can see more than expected
    # replica change events, but never less than expected
    assert int(result) >= expected_count


def update_configs(node_1_sleep_in_send_tables_status=0, node_1_sleep_in_send_data=0,
                    node_2_sleep_in_send_tables_status=0, node_2_sleep_in_send_data=0,
                    node_3_sleep_in_send_tables_status=0, node_3_sleep_in_send_data=0):
    NODES['node_1'].replace_config(
        '/etc/clickhouse-server/users.d/users1.xml',
        config.format(sleep_in_send_tables_status_ms=node_1_sleep_in_send_tables_status, sleep_in_send_data_ms=node_1_sleep_in_send_data))

    NODES['node_2'].replace_config(
        '/etc/clickhouse-server/users.d/users1.xml',
        config.format(sleep_in_send_tables_status_ms=node_2_sleep_in_send_tables_status, sleep_in_send_data_ms=node_2_sleep_in_send_data))

    NODES['node_3'].replace_config(
        '/etc/clickhouse-server/users.d/users1.xml',
        config.format(sleep_in_send_tables_status_ms=node_3_sleep_in_send_tables_status, sleep_in_send_data_ms=node_3_sleep_in_send_data))

    check_settings('node_1', node_1_sleep_in_send_tables_status, node_1_sleep_in_send_data)
    check_settings('node_2', node_2_sleep_in_send_tables_status, node_2_sleep_in_send_data)
    check_settings('node_3', node_3_sleep_in_send_tables_status, node_3_sleep_in_send_data)


def test_stuck_replica(started_cluster):
    update_configs()

    cluster.pause_container("node_1")

    check_query(expected_replica="node_2")
    check_changing_replica_events(1)

    result = NODES['node'].query("SELECT slowdowns_count FROM system.clusters WHERE cluster='test_cluster' and host_name='node_1'")

    assert TSV(result) == TSV("1")

    result = NODES['node'].query("SELECT hostName(), id FROM distributed ORDER BY id LIMIT 1");

    assert TSV(result) == TSV("node_2\t0")

    # Check that we didn't choose node_1 first again and slowdowns_count didn't increase.
    result = NODES['node'].query("SELECT slowdowns_count FROM system.clusters WHERE cluster='test_cluster' and host_name='node_1'")

    assert TSV(result) == TSV("1")

    cluster.unpause_container("node_1")


def test_long_query(started_cluster):
    update_configs()

    # Restart to reset pool states.
    NODES['node'].restart_clickhouse()

    result = NODES['node'].query("select hostName(), max(id + sleep(1.5)) from distributed settings max_block_size = 1, max_threads = 1;")
    assert TSV(result) == TSV("node_1\t99")

    NODES['node'].query("INSERT INTO distributed select number, toDate(number) from numbers(100);")


def test_send_table_status_sleep(started_cluster):
    update_configs(node_1_sleep_in_send_tables_status=sleep_time)
    check_query(expected_replica="node_2")
    check_changing_replica_events(1)


def test_send_table_status_sleep2(started_cluster):
    update_configs(node_1_sleep_in_send_tables_status=sleep_time, node_2_sleep_in_send_tables_status=sleep_time)
    check_query(expected_replica="node_3")
    check_changing_replica_events(2)


def test_send_data(started_cluster):
    update_configs(node_1_sleep_in_send_data=sleep_time)
    check_query(expected_replica="node_2")
    check_changing_replica_events(1)


def test_send_data2(started_cluster):
    update_configs(node_1_sleep_in_send_data=sleep_time, node_2_sleep_in_send_data=sleep_time)
    check_query(expected_replica="node_3")
    check_changing_replica_events(2)


def test_combination1(started_cluster):
    update_configs(node_1_sleep_in_send_tables_status=sleep_time, node_2_sleep_in_send_data=sleep_time)
    check_query(expected_replica="node_3")
    check_changing_replica_events(2)


def test_combination2(started_cluster):
    update_configs(node_1_sleep_in_send_data=sleep_time, node_2_sleep_in_send_tables_status=sleep_time)
    check_query(expected_replica="node_3")
    check_changing_replica_events(2)


def test_combination3(started_cluster):
    update_configs(node_1_sleep_in_send_data=sleep_time,
                    node_2_sleep_in_send_tables_status=1000,
                    node_3_sleep_in_send_data=sleep_time)
    check_query(expected_replica="node_2")
    check_changing_replica_events(3)


def test_combination4(started_cluster):
    update_configs(node_1_sleep_in_send_tables_status=1000,
                    node_1_sleep_in_send_data=sleep_time,
                    node_2_sleep_in_send_tables_status=1000,
                    node_3_sleep_in_send_tables_status=1000)
    check_query(expected_replica="node_2")
    check_changing_replica_events(4)


def test_receive_timeout1(started_cluster):
    # Check the situation when first two replicas get receive timeout
    # in establishing connection, but the third replica is ok.
    update_configs(node_1_sleep_in_send_tables_status=3000,
                    node_2_sleep_in_send_tables_status=3000,
                    node_3_sleep_in_send_data=1000)
    check_query(expected_replica="node_3", receive_timeout=2)
    check_changing_replica_events(2)


def test_receive_timeout2(started_cluster):
    # Check the situation when first replica get receive timeout
    # in packet receiving but there are replicas in process of
    # connection establishing.
    update_configs(node_1_sleep_in_send_data=4000,
                    node_2_sleep_in_send_tables_status=2000,
                    node_3_sleep_in_send_tables_status=2000)
    check_query(expected_replica="node_2", receive_timeout=3)
    check_changing_replica_events(3)