query_metric_log

Querying in ClickHouse Cloud

The data in this system table is held locally on each node in ClickHouse Cloud. Obtaining a complete view of all data, therefore, requires the clusterAllReplicas function. See here for further details.

Contains a history of memory and metric values from table system.events for individual queries, periodically flushed to disk.

Once a query starts, data is collected at periodic intervals of query_metric_log_interval milliseconds (which is set to 1000 by default). The data is also collected when the query finishes if the query takes longer than query_metric_log_interval.

Columns:

• query_id (String) — ID of the query.
• hostname (LowCardinality(String)) — Hostname of the server executing the query.
• event_date (Date) — Event date.
• event_time (DateTime) — Event time.
• event_time_microseconds (DateTime64) — Event time with microseconds resolution.

Example

See also

• query_metric_log setting — Enabling and disabling the setting.
• query_metric_log_interval
• system.asynchronous_metrics — Contains periodically calculated metrics.
• system.events — Contains a number of events that occurred.
• system.metrics — Contains instantly calculated metrics.
• Monitoring — Base concepts of ClickHouse monitoring.