64 lines
2.5 KiB
Markdown
64 lines
2.5 KiB
Markdown
---
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title: InfluxDB system tables
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description: >
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InfluxDB system measurements contain time series data used by and generated from the
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InfluxDB internal monitoring system.
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menu:
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influxdb_clustered:
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name: System tables
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parent: InfluxDB internals
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weight: 103
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influxdb/clustered/tags: [tables, information schema]
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related:
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- /influxdb/clustered/reference/sql/information-schema/
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---
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{{% warn %}}
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Queries of InfluxDB system tables may affect production performance while
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system tables are accessed.
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System tables are not currently part of the stable API and the schema may change
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in subsequent releases.
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{{% /warn %}}
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InfluxDB system measurements contain time series data used by and generated from the
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InfluxDB internal monitoring system.
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Each InfluxDB Clustered namespace includes the following system measurements:
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- [queries](#_queries-system-measurement)
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## queries system measurement
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The `system.queries` measurement stores log entries for queries executed for the provided namespace (database) on the node that is currently handling queries.
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The following example shows how to list queries recorded in the `system.queries` measurement:
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```sql
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SELECT issue_time, query_type, query_text, success FROM system.queries;
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```
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_When listing measurements (tables) available within a namespace, some clients and query tools may include the `queries` table in the list of namespace tables._
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`system.queries` reflects a process-local, in-memory, namespace-scoped query log.
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While this table may be useful for debugging and monitoring queries, keep the following in mind:
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- Records stored in `system.queries` are volatile.
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- Records are lost on pod restarts.
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- Queries for one namespace can evict records from another namespace.
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- Data reflects the state of a specific pod answering queries for the namespace.
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- A query for records in `system.queries` can return different results depending on the pod the request was routed to.
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**Data retention:** System data can be transient and is deleted on pod restarts.
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### queries measurement schema
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- **system.queries** _(measurement)_
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- **fields**:
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- **issue_time**: timestamp when the query was issued
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- **query_type**: type (syntax: `sql`, `flightsql`, or `influxql`) of the query
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- **query_text**: query statement text
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- **success**: execution status (boolean) of the query
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- **completed_duration**: time (duration) that the query took to complete
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- **trace_id**: trace ID for debugging and monitoring events
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