ClickHouse/tests/performance/parallel_insert.xml

<test>

    <preconditions>
        <table_exists>default.hits_10m_single</table_exists>
    </preconditions>

    <create_query>
        CREATE TABLE hits2 ENGINE MergeTree
        PARTITION BY toYYYYMM(EventDate)
        ORDER BY (CounterID, EventDate, intHash32(UserID))
        SAMPLE BY intHash32(UserID)
        SETTINGS
            parts_to_delay_insert = 5000,
            parts_to_throw_insert = 5000
        AS
            -- don't select all columns to keep the run time down
            SELECT CounterID, EventDate, UserID, Title
            FROM hits_10m_single
            -- do not select anything because we only need column types
            LIMIT 0
    </create_query>
    <fill_query>SET max_insert_threads=8</fill_query>
    <fill_query>SYSTEM STOP MERGES</fill_query>

    <query>
        INSERT INTO hits2
        SELECT CounterID, EventDate, UserID, Title
        FROM hits_10m_single
    </query>

    <drop_query>SYSTEM START MERGES</drop_query>
    <drop_query>DROP TABLE IF EXISTS hits2</drop_query>
</test>