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> System table containing historical values for `system.asynchronous_metrics`, which are saved once per time interval (one second by default)

# system.asynchronous_metric_log

<Info>
  **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](/reference/system-tables/overview#system-tables-in-clickhouse-cloud) for further details.
</Info>

<h2 id="description">
  Description
</h2>

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

<h2 id="columns">
  Columns
</h2>

* `hostname` ([LowCardinality(String)](/reference/data-types/lowcardinality)) — Hostname of the server executing the query.
* `event_date` ([Date](/reference/data-types/date)) — Event date.
* `event_time` ([DateTime](/reference/data-types/datetime)) — Event time.
* `metric` ([LowCardinality(String)](/reference/data-types/lowcardinality)) — Metric name.
* `value` ([Float64](/reference/data-types/float)) — Metric value.

<h2 id="example">
  Example
</h2>

```sql theme={null}
SELECT * FROM system.asynchronous_metric_log LIMIT 3 \G
```

```text theme={null}
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](/reference/settings/server-settings/settings#asynchronous_metric_log) — Enabling and disabling the setting.
* [system.asynchronous\_metrics](/reference/system-tables/asynchronous_metrics) — Contains metrics, calculated periodically in the background.
* [system.metric\_log](/reference/system-tables/metric_log) — Contains history of metrics values from tables `system.metrics` and `system.events`, periodically flushed to disk.