174 lines
5.6 KiB
Markdown
174 lines
5.6 KiB
Markdown
---
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title: InfluxDB query management
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menu:
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influxdb_1_5:
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name: Query management
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weight: 20
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parent: Troubleshooting
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---
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With InfluxDB's query management features, users are able to
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identify currently-running queries,
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kill queries that are overloading their system,
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and prevent and halt the execution of inefficient queries with several configuration settings.
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<table style="width:100%">
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<tr>
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<td><a href="#list-currently-running-queries-with-show-queries">SHOW QUERIES</a></td>
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<td><a href="#stop-currently-running-queries-with-kill-query">KILL QUERY</a></td>
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<td><a href="#configuration-settings-for-query-management">Configuration Settings</a></td>
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</tr>
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</table>
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## List currently-running queries with `SHOW QUERIES`
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`SHOW QUERIES` lists the query id, query text, relevant database, and duration
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of all currently-running queries on your InfluxDB instance.
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#### Syntax:
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```
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SHOW QUERIES
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```
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#### Example:
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```
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> SHOW QUERIES
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qid query database duration
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37 SHOW QUERIES 100368u
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36 SELECT mean(myfield) FROM mymeas mydb 3s
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```
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##### Explanation of the output:
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<br>
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- `qid`    The id number of the query. Use this value with [`KILL - QUERY`](/influxdb/v1.5/troubleshooting/query_management/#stop-currently-running-queries-with-kill-query).
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- `query`    The query text.
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- `database` The database targeted by the query.
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- `duration` The length of time that the query has been running.
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See [Query Language Reference](/influxdb/v1.5/query_language/spec/#durations)
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for an explanation of InfluxDB's time units.
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## Stop currently-running queries with `KILL QUERY`
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`KILL QUERY` tells InfluxDB to stop running the relevant query.
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#### Syntax:
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Where `qid` is the query ID, displayed in the [`SHOW QUERIES`](/influxdb/v1.3/troubleshooting/query_management/#list-currently-running-queries-with-show-queries) output:
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```
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KILL QUERY <qid>
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```
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***InfluxDB Enterprise clusters:*** To kill queries on a cluster, you need to specify the query ID (qid) and the TCP host (for example, `myhost:8088`),
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available in the `SHOW QUERIES` output.
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```
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KILL QUERY <qid> ON "<host>"
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```
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A successful `KILL QUERY` query returns no results.
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#### Examples:
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```
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-- kill query with qid of 36 on the local host
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> KILL QUERY 36
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>
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```
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```
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-- kill query on InfluxDB Enterprise cluster
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> KILL QUERY 53 ON "myhost:8088"
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>
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```
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## Configuration settings for query management
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The following configuration settings are in the
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[[coordinator]](/influxdb/v1.5/administration/config/#query-management-settings-coordinator) section of the
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configuration file.
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### max-concurrent-queries
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The maximum number of running queries allowed on your instance.
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The default setting (`0`) allows for an unlimited number of queries.
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If you exceed `max-concurrent-queries`, InfluxDB does not execute the query and
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outputs the following error:
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```
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ERR: max concurrent queries reached
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```
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### query-timeout
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The maximum time for which a query can run on your instance before InfluxDB
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kills the query.
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The default setting (`"0"`) allows queries to run with no time restrictions.
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This setting is a [duration literal](/influxdb/v1.5/query_language/spec/#durations).
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If your query exceeds the query timeout, InfluxDB kills the query and outputs
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the following error:
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```
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ERR: query timeout reached
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```
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### log-queries-after
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The maximum time a query can run after which InfluxDB logs the query with a
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`Detected slow query` message.
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The default setting (`"0"`) will never tell InfluxDB to log the query.
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This setting is a [duration literal](/influxdb/v1.5/query_language/spec/#durations).
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Example log output with `log-queries-after` set to `"1s"`:
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```
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[query] 2016/04/28 14:11:31 Detected slow query: SELECT mean(usage_idle) FROM cpu WHERE time >= 0 GROUP BY time(20s) (qid: 3, database: telegraf, threshold: 1s)
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```
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`qid` is the id number of the query.
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Use this value with [`KILL QUERY`](/influxdb/v1.5/troubleshooting/query_management/#stop-currently-running-queries-with-kill-query).
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The default location for the log output file is `/var/log/influxdb/influxdb.log`. However on systems that use systemd (most modern Linux distributions) those logs are output to `journalctl`. You should be able to view the InfluxDB logs using the following command: `journalctl -u influxdb`
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### max-select-point
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The maximum number of [points](/influxdb/v1.5/concepts/glossary/#point) that a
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`SELECT` statement can process.
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The default setting (`0`) allows the `SELECT` statement to process an unlimited
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number of points.
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If your query exceeds `max-select-point`, InfluxDB kills the query and outputs
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the following error:
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```
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ERR: max number of points reached
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```
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InfluxDB checks the point count every second (so queries exceeding the maximum aren’t immediately aborted).
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### max-select-series
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The maximum number of [series](/influxdb/v1.5/concepts/glossary/#series) that a
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`SELECT` statement can process.
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The default setting (`0`) allows the `SELECT` statement to process an unlimited
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number of series.
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If your query exceeds `max-select-series`, InfluxDB does not execute the query
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and outputs the following error:
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```
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ERR: max select series count exceeded: <query_series_count> series
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```
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### max-select-buckets
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The maximum number of `GROUP BY time()` buckets that a query can process.
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The default setting (`0`) allows a query to process an unlimited number of
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buckets.
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If your query exceeds `max-select-buckets`, InfluxDB does not execute the query
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and outputs the following error:
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```
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ERR: max select bucket count exceeded: <query_bucket_count> buckets
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```
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