histogram_metrics

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.

This table contains histogram metrics that can be calculated instantly and exported in the Prometheus format. It is always up to date. Replaces the deprecated system.latency_log.

Columns:

• metric (String) — Metric name.
• value (Int64) — Metric value.
• description (String) — Metric description.
• labels (Map(String, String)) — Metric labels.

Example

You can use a query like this to export all the histogram metrics in the Prometheus format.

SELECT
  metric AS name,
  toFloat64(value) AS value,
  description AS help,
  labels,
  'histogram' AS type
FROM system.histogram_metrics
FORMAT Prometheus

Metric descriptions

keeper_response_time_ms_bucket

The response time of Keeper, in milliseconds.

keeper_client_queue_duration_milliseconds_bucket

Time requests spend waiting to be enqueued and waiting in the queue before being processed by the Keeper client, in milliseconds.

keeper_receive_request_time_milliseconds_bucket

Time to receive and parse a request from the client in the Keeper TCP handler, in milliseconds.

keeper_dispatcher_requests_queue_time_milliseconds_bucket

Time a request spends in the Keeper dispatcher requests queue, in milliseconds.

keeper_write_pre_commit_time_milliseconds_bucket

Time to preprocess a write request before Raft commit, in milliseconds.

keeper_write_commit_time_milliseconds_bucket

Time to process a write request after Raft commit, in milliseconds.

keeper_dispatcher_responses_queue_time_milliseconds_bucket

Time a response spends in the Keeper dispatcher responses queue, in milliseconds.

keeper_send_response_time_milliseconds_bucket

Time to send a response to the client in the Keeper TCP handler (includes queueing and writing to socket), in milliseconds.

keeper_read_wait_for_write_time_milliseconds_bucket

Time a read request waits for the write request it depends on to complete, in milliseconds.

keeper_read_process_time_milliseconds_bucket

Time to process a read request in Keeper, in milliseconds.

keeper_batch_size_elements_bucket

Batch size sent to Raft, in elements.

keeper_batch_size_bytes_bucket

Batch size sent to Raft, in bytes.

See Also

• system.asynchronous_metrics — Contains periodically calculated metrics.
• system.events — Contains a number of events that occurred.
• system.metric_log — Contains a history of metrics values from tables system.metrics and system.events.
• Monitoring — Base concepts of ClickHouse monitoring.