Show databases

List all databases in ClickHouse

clickhouse-client -q 'SHOW DATABASES'
tool
clickhouse17 commands
tags
clickhouse

More clickhouse commands

  • Show tables
    clickhouse-client -q 'SHOW TABLES FROM mydb'

    List all tables in a database

  • Table size
    clickhouse-client -q "SELECT table, formatReadableSize(sum(bytes)) AS size FROM system.parts WHERE active AND database='mydb' GROUP BY table ORDER BY sum(bytes) DESC"

    Show disk usage per table in a database

  • Running queries
    clickhouse-client -q 'SELECT query_id, user, elapsed, query FROM system.processes ORDER BY elapsed DESC'

    List all currently running queries with elapsed time

  • Kill query
    clickhouse-client -q "KILL QUERY WHERE query_id='<id>'"

    Terminate a long-running or stuck query

  • Drop caches
    clickhouse-client -q 'SYSTEM DROP MARK CACHE; SYSTEM DROP UNCOMPRESSED CACHE'

    Flush ClickHouse caches to free memory

all 17 clickhouse commands