Query Management

With InfluxDB’s query management features, users are able to identify currently-running queries, kill queries that are overloading their system, and prevent and halt the execution of inefficient queries with several configuration settings.

SHOW QUERIES KILL QUERY Configuration Settings

List currently-running queries with SHOW QUERIES

SHOW QUERIES lists the query id, query text, relevant database, and duration of all currently-running queries on your InfluxDB instance.

Syntax:

SHOW QUERIES

Example:

> SHOW QUERIES
qid	  query															               database		  duration
37	   SHOW QUERIES																                	  100368u
36	   SELECT mean(myfield) FROM mymeas   mydb        3s
Explanation of the output:


qid    The id number of the query. Use this value with KILL QUERY.
query    The query text.
database The database targeted by the query.
duration The length of time that the query has been running. See Query Language Reference for an explanation of InfluxDB’s time units.

Stop currently-running queries with KILL QUERY

KILL QUERY tells InfluxDB to stop running the relevant query.

Syntax:

Where qid is the id of the query from the SHOW QUERIES output:

KILL QUERY <qid>

Example:


> KILL QUERY 36
>

A successful KILL QUERY query returns no results.

Configuration settings for query management

The following configuration settings are in the [coordinator] section of the configuration file.

max-concurrent-queries

The maximum number of running queries allowed on your instance. The default setting (0) allows for an unlimited number of queries.

If you exceed max-concurrent-queries, InfluxDB does not execute the query and outputs the following error:

ERR: max concurrent queries reached

query-timeout

The maximum time for which a query can run on your instance before InfluxDB kills the query. The default setting ("0") allows queries to run with no time restrictions. This setting is a duration literal.

If your query exceeds the query timeout, InfluxDB kills the query and outputs the following error:

ERR: query timeout reached

log-queries-after

The maximum time a query can run after which InfluxDB logs the query with a Detected slow query message. The default setting ("0") will never tell InfluxDB to log the query. This setting is a duration literal.

Example log output with log-queries-after set to "1s":

[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)

qid is the id number of the query. Use this value with KILL QUERY.

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

max-select-point

The maximum number of points that a SELECT statement can process. The default setting (0) allows the SELECT statement to process an unlimited number of points.

If your query exceeds max-select-point, InfluxDB kills the query and outputs the following error:

ERR: max number of points reached

max-select-series

The maximum number of series that a SELECT statement can process. The default setting (0) allows the SELECT statement to process an unlimited number of series.

If your query exceeds max-select-series, InfluxDB does not execute the query and outputs the following error:

ERR: max select series count exceeded: <query_series_count> series

max-select-buckets

The maximum number of GROUP BY time() buckets that a query can process. The default setting (0) allows a query to process an unlimited number of buckets.

If your query exceeds max-select-buckets, InfluxDB does not execute the query and outputs the following error:

ERR: max select bucket count exceeded: <query_bucket_count> buckets

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