Check running queries

List longest running queries in the system

clickhouse-client -q 'SELECT query_id, elapsed, query FROM system.processes ORDER BY elapsed DESC LIMIT 10'
tool
clickhouse17 commands
tags
clickhousedebugmonitoring

More clickhouse commands

  • Kill a running query
    clickhouse-client -q "KILL QUERY WHERE query_id = 'abc-123'"

    Force-stop a specific query by its query_id

  • Table disk usage
    clickhouse-client -q 'SELECT database, table, formatReadableSize(sum(bytes_on_disk)) AS size FROM system.parts GROUP BY database, table ORDER BY sum(bytes_on_disk) DESC LIMIT 20'

    Top 20 tables by on-disk size

  • Optimize table (force merge)
    clickhouse-client -q 'OPTIMIZE TABLE mydb.mytable FINAL'

    Force merging of all parts (use with caution on large tables)

  • Ingest CSV from file
    clickhouse-client --query 'INSERT INTO mydb.events FORMAT CSVWithNames' < events.csv

    Bulk-load a CSV file into a ClickHouse table

  • Check replication status
    clickhouse-client -q 'SELECT database, table, is_leader, queue_size, absolute_delay FROM system.replicas WHERE absolute_delay > 0'

    Show replication lag on delayed replicas

all 17 clickhouse commands