Table disk usage

Top 20 tables by on-disk size

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'
tool
clickhouse17 commands
tags
clickhousemonitoring

More clickhouse commands

  • 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

  • Slowest recent queries
    clickhouse-client -q "SELECT query_duration_ms, formatReadableSize(memory_usage) mem, substring(query,1,80) FROM system.query_log WHERE type=2 AND event_time>now()-3600 ORDER BY query_duration_ms DESC LIMIT 10"

    Top slow finished queries last hour with memory; type=2 = QueryFinish

  • Pending mutations
    clickhouse-client -q "SELECT database, table, mutation_id, latest_fail_reason FROM system.mutations WHERE is_done=0"

    Find stuck ALTER/DELETE mutations with failure reason; blocks schema changes

all 17 clickhouse commands