system.asynchronous_metric_log

import SystemTableCloud from '@site/docs/_snippets/_system_table_cloud.md';

Contains the historical values for system.asynchronous_metrics, which are saved once per time interval (one second by default). Enabled by default.

Columns:

• hostname (LowCardinality(String)) — Hostname of the server executing the query.
• event_date (Date) — Event date.
• event_time (DateTime) — Event time.
• metric (String) — Metric name.
• value (Float64) — Metric value.

Example

SELECT * FROM system.asynchronous_metric_log LIMIT 3 \G

Row 1:
──────
hostname:   clickhouse.eu-central1.internal
event_date: 2023-11-14
event_time: 2023-11-14 14:39:07
metric:     AsynchronousHeavyMetricsCalculationTimeSpent
value:      0.001

Row 2:
──────
hostname:   clickhouse.eu-central1.internal
event_date: 2023-11-14
event_time: 2023-11-14 14:39:08
metric:     AsynchronousHeavyMetricsCalculationTimeSpent
value:      0

Row 3:
──────
hostname:   clickhouse.eu-central1.internal
event_date: 2023-11-14
event_time: 2023-11-14 14:39:09
metric:     AsynchronousHeavyMetricsCalculationTimeSpent
value:      0

See Also

• asynchronous_metric_log setting — Enabling and disabling the setting.
• system.asynchronous_metrics — Contains metrics, calculated periodically in the background.
• system.metric_log — Contains history of metrics values from tables system.metrics and system.events, periodically flushed to disk.