metric_log
Contains history of metrics values from tables system.metrics
and system.events
, periodically flushed to disk.
Columns:
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
SELECT * FROM system.metric_log LIMIT 1 FORMAT Vertical;
Row 1:
──────
hostname: clickhouse.eu-central1.internal
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 — Enabling and disabling the setting.
- 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.