ClickHouse/docs/en/operations/system-tables/metric_log.md
2021-06-24 20:47:02 +08:00

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# system.metric_log {#system_tables-metric_log}
Contains history of metrics values from tables `system.metrics` and `system.events`, periodically flushed to disk.
Columns:
- `event_date` ([Date](../../sql-reference/data-types/date.md)) — Event date.
- `event_time` ([DateTime](../../sql-reference/data-types/datetime.md)) — Event time.
- `event_time_microseconds` ([DateTime64](../../sql-reference/data-types/datetime64.md)) — Event time with microseconds resolution.
**Example**
``` sql
SELECT * FROM system.metric_log LIMIT 1 FORMAT Vertical;
```
``` text
Row 1:
──────
event_date: 2020-09-05
event_time: 2020-09-05 16:22:33
event_time_microseconds: 2020-09-05 16:22:33.196807
milliseconds: 196
ProfileEvent_Query: 0
ProfileEvent_SelectQuery: 0
ProfileEvent_InsertQuery: 0
ProfileEvent_FailedQuery: 0
ProfileEvent_FailedSelectQuery: 0
...
...
CurrentMetric_Revision: 54439
CurrentMetric_VersionInteger: 20009001
CurrentMetric_RWLockWaitingReaders: 0
CurrentMetric_RWLockWaitingWriters: 0
CurrentMetric_RWLockActiveReaders: 0
CurrentMetric_RWLockActiveWriters: 0
CurrentMetric_GlobalThread: 74
CurrentMetric_GlobalThreadActive: 26
CurrentMetric_LocalThread: 0
CurrentMetric_LocalThreadActive: 0
CurrentMetric_DistributedFilesToInsert: 0
```
**See also**
- [metric_log setting](../../operations/server-configuration-parameters/settings.md#metric_log) — Enabling and disabling the setting.
- [system.asynchronous_metrics](../../operations/system-tables/asynchronous_metrics.md) — Contains periodically calculated metrics.
- [system.events](../../operations/system-tables/events.md#system_tables-events) — Contains a number of events that occurred.
- [system.metrics](../../operations/system-tables/metrics.md) — Contains instantly calculated metrics.
- [Monitoring](../../operations/monitoring.md) — Base concepts of ClickHouse monitoring.
[Original article](https://clickhouse.tech/docs/en/operations/system-tables/metric_log) <!--hide-->