ClickHouse/tests/integration/test_hedged_requests_parallel/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

cluster = ClickHouseCluster(__file__)

NODES = {'node_' + str(i): None for i in (1, 2, 3, 4)}
NODES['node'] = None

# Cleep time in milliseconds.
sleep_time = 30000

@pytest.fixture(scope="module")
def started_cluster():
    cluster = ClickHouseCluster(__file__)
    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, toDateTime(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>'''


QUERY_1 = "SELECT count() FROM distributed"
QUERY_2 = "SELECT * FROM distributed"


def check_query(query=QUERY_1):
    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()
    NODES['node'].query(query);
    query_time = time.time() - start
    print("Query time:", query_time)

    assert query_time < 5


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,
                    node_4_sleep_in_send_tables_status=0, node_4_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))

    NODES['node_4'].replace_config(
        '/etc/clickhouse-server/users.d/users1.xml',
        config.format(sleep_in_send_tables_status_ms=node_4_sleep_in_send_tables_status, sleep_in_send_data_ms=node_4_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)
    check_settings('node_4', node_4_sleep_in_send_tables_status, node_4_sleep_in_send_data)


def test_send_table_status_sleep(started_cluster):
    update_configs(node_1_sleep_in_send_tables_status=sleep_time, node_2_sleep_in_send_tables_status=sleep_time)
    check_query()
    check_changing_replica_events(2)


def test_send_data(started_cluster):
    update_configs(node_1_sleep_in_send_data=sleep_time, node_2_sleep_in_send_data=sleep_time)
    check_query()
    check_changing_replica_events(2)


def test_combination1(started_cluster):
    update_configs(node_1_sleep_in_send_tables_status=1000,
                    node_2_sleep_in_send_tables_status=1000,
                    node_3_sleep_in_send_data=sleep_time)
    check_query()
    check_changing_replica_events(3)


def test_combination2(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,
                    node_4_sleep_in_send_tables_status=1000)
    check_query()
    check_changing_replica_events(4)


def test_query_with_no_data_to_sample(started_cluster):
    update_configs(node_1_sleep_in_send_data=sleep_time,
                    node_2_sleep_in_send_data=sleep_time)

    # When there is no way to sample data, the whole query will be performed by
    # the first replica and the second replica will just send EndOfStream,
    # so we will change only the first replica here.
    check_query(query=QUERY_2)
    check_changing_replica_events(1)