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55 lines
2.8 KiB
Markdown
55 lines
2.8 KiB
Markdown
---
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slug: /en/operations/system-tables/metric_log
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---
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# metric_log
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Contains history of metrics values from tables `system.metrics` and `system.events`, periodically flushed to disk.
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Columns:
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- `hostname` ([LowCardinality(String)](../../sql-reference/data-types/string.md)) — Hostname of the server executing the query.
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- `event_date` ([Date](../../sql-reference/data-types/date.md)) — Event date.
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- `event_time` ([DateTime](../../sql-reference/data-types/datetime.md)) — Event time.
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- `event_time_microseconds` ([DateTime64](../../sql-reference/data-types/datetime64.md)) — Event time with microseconds resolution.
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**Example**
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``` sql
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SELECT * FROM system.metric_log LIMIT 1 FORMAT Vertical;
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```
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``` text
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Row 1:
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──────
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hostname: clickhouse.eu-central1.internal
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event_date: 2020-09-05
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event_time: 2020-09-05 16:22:33
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event_time_microseconds: 2020-09-05 16:22:33.196807
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milliseconds: 196
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ProfileEvent_Query: 0
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ProfileEvent_SelectQuery: 0
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ProfileEvent_InsertQuery: 0
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ProfileEvent_FailedQuery: 0
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ProfileEvent_FailedSelectQuery: 0
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...
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...
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CurrentMetric_Revision: 54439
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CurrentMetric_VersionInteger: 20009001
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CurrentMetric_RWLockWaitingReaders: 0
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CurrentMetric_RWLockWaitingWriters: 0
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CurrentMetric_RWLockActiveReaders: 0
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CurrentMetric_RWLockActiveWriters: 0
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CurrentMetric_GlobalThread: 74
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CurrentMetric_GlobalThreadActive: 26
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CurrentMetric_LocalThread: 0
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CurrentMetric_LocalThreadActive: 0
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CurrentMetric_DistributedFilesToInsert: 0
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```
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**See also**
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- [metric_log setting](../../operations/server-configuration-parameters/settings.md#metric_log) — Enabling and disabling the setting.
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- [system.asynchronous_metrics](../../operations/system-tables/asynchronous_metrics.md) — Contains periodically calculated metrics.
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- [system.events](../../operations/system-tables/events.md#system_tables-events) — Contains a number of events that occurred.
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- [system.metrics](../../operations/system-tables/metrics.md) — Contains instantly calculated metrics.
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- [Monitoring](../../operations/monitoring.md) — Base concepts of ClickHouse monitoring.
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