This is archived documentation for InfluxData product versions that are no longer maintained. For newer documentation, see the latest InfluxData documentation.
With InfluxDB’s query management features, users are able to identify currently-running queries and have the ability to kill queries that are overloading their system. Additionally, users can prevent and halt the execution of inefficient queries with several configuration settings.
- List currently-running queries with
SHOW QUERIES - Stop currently-running queries with
KILL QUERY - Configuration settings for query management
- Limit the number of running queries with
max-concurrent-queries - Set a query timeout with
query-timeout - Log queries if they run longer than specified time with
log-queries-after - Limit the number of points that a
SELECTstatement can process withmax-select-point - Limit the number of series that a
SELECTstatement can process withmax-select-series - Limit the number of
GROUP BY time()buckets a query can process withmax-select-buckets
- Limit the number of running queries with
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 [cluster] 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.
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