--- title: QueryNode description: > QueryNode defines a source and a schedule for processing batch data. The data is queried from an InfluxDB database and then passed into the data pipeline. note: Auto generated by tickdoc menu: kapacitor_1_5_ref: name: QueryNode identifier: query_node weight: 220 parent: nodes --- The `query` node defines a source and a schedule for processing batch data. Data is queried from InfluxDB, computed by the `query` node, and then passed into the data pipeline. Example: ```js batch |query(''' SELECT mean("value") FROM "telegraf"."default".cpu_usage_idle WHERE "host" = 'serverA' ''') .period(1m) .every(20s) .groupBy(time(10s), 'cpu') ... ``` In the example above, InfluxDB is queried every 20 seconds; the window of time returned spans 1 minute and is grouped into 10 second buckets. To use InfluxQL advanced syntax for functions in the `query` node, you must express part of the InfluxQL query in the TICKScript. Advanced syntax computes the nested aggregation over time buckets, and then applies the outer aggregate on the results. For example, the following InfluxQL script, which calculates the non-negative difference of the 10-second mean of cpu usage for every cpu, isn't valid for the `query` node: ```js SELECT non_negative_difference(mean("value")) FROM "telegraf"."default"."cpu_usage_idle" WHERE "host" = 'serverA' GROUP BY time(10s), "cpu" ... ``` To calculate the result above for the `query` node, you must specify grouping and the outer aggregate using TICKScript: ```js batch |query(''' SELECT mean("value") FROM "telegraf"."default".cpu_usage_idle WHERE "host" = 'serverA' ''') .period(1m) .every(1m) .groupBy(time(10s), 'cpu') | difference('max_usage') | where(lambda: "difference" >= 0) ... ``` ### Constructor | Chaining Method | Description | |:---------|:---------| | **query ( `q` `string`)** | The query to execute. Must not contain a time condition in the `WHERE` clause or contain a `GROUP BY` clause. The time conditions are added dynamically according to the period, offset and schedule. The `GROUP BY` clause is added dynamically according to the dimensions passed to the `groupBy` method. | ### Property Methods | Setters | Description | |:---|:---| | **[align](#align) ( )** | Align start and stop times for queries with even boundaries of the QueryNode.Every property. Does not apply if using the QueryNode.Cron property. | | **[alignGroup](#aligngroup) ( )** | Align the group by time intervals with the start time of the query | | **[cluster](#cluster) ( `value` `string`)** | The name of a configured InfluxDB cluster. If empty the default cluster will be used. | | **[cron](#cron) ( `value` `string`)** | Define a schedule using a cron syntax. | | **[every](#every) ( `value` `time.Duration`)** | How often to query InfluxDB. | | **[fill](#fill) ( `value` `interface{}`)** | Fill the data. Options are: | | **[groupBy](#groupby) ( `d` `...interface{}`)** | Group the data by a set of dimensions. Can specify one time dimension. | | **[groupByMeasurement](#groupbymeasurement) ( )** | If set will include the measurement name in the group ID. Along with any other group by dimensions. | | **[offset](#offset) ( `value` `time.Duration`)** | How far back in time to query from the current time | | **[period](#period) ( `value` `time.Duration`)** | The period or length of time that will be queried from InfluxDB | | **[quiet](#quiet) ( )** | Suppress all error logging events from this node. | ### Chaining Methods [Alert](#alert), [Barrier](#barrier), [Bottom](#bottom), [ChangeDetect](#changedetect), [Combine](#combine), [Count](#count), [CumulativeSum](#cumulativesum), [Deadman](#deadman), [Default](#default), [Delete](#delete), [Derivative](#derivative), [Difference](#difference), [Distinct](#distinct), [Ec2Autoscale](#ec2autoscale), [Elapsed](#elapsed), [Eval](#eval), [First](#first), [Flatten](#flatten), [HoltWinters](#holtwinters), [HoltWintersWithFit](#holtwinterswithfit), [HttpOut](#httpout), [HttpPost](#httppost), [InfluxDBOut](#influxdbout), [Join](#join), [K8sAutoscale](#k8sautoscale), [KapacitorLoopback](#kapacitorloopback), [Last](#last), [Log](#log), [Max](#max), [Mean](#mean), [Median](#median), [Min](#min), [Mode](#mode), [MovingAverage](#movingaverage), [Percentile](#percentile), [Sample](#sample), [Shift](#shift), [Sideload](#sideload), [Spread](#spread), [StateCount](#statecount), [StateDuration](#stateduration), [Stats](#stats), [Stddev](#stddev), [Sum](#sum), [SwarmAutoscale](#swarmautoscale), [Top](#top), [Union](#union), [Where](#where), [Window](#window) --- ## Properties Property methods modify state on the calling node. They do not add another node to the pipeline, and always return a reference to the calling node. Property methods are marked using the `.` operator. ### Align Align start and stop times for queries with even boundaries of the [QueryNode.Every](/kapacitor/v1.5/nodes/query_node/#every) property. Does not apply if using the [QueryNode.Cron](/kapacitor/v1.5/nodes/query_node/#cron) property. ```js query.align() ``` ### AlignGroup Align the group by time intervals with the start time of the query ```js query.alignGroup() ``` ### Cluster The name of a configured InfluxDB cluster. If empty the default cluster will be used. ```js query.cluster(value string) ``` ### Cron Define a schedule using a cron syntax. The specific cron implementation is documented here: https://github.com/gorhill/cronexpr#implementation The Cron property is mutually exclusive with the Every property. ```js query.cron(value string) ``` ### Every How often to query InfluxDB. The Every property is mutually exclusive with the Cron property. ```js query.every(value time.Duration) ``` ### Fill Fill the data. Options are: - Any numerical value - null - exhibits the same behavior as the default - previous - reports the value of the previous window - none - suppresses timestamps and values where the value is null - linear - reports the results of linear interpolation ```js query.fill(value interface{}) ``` ### GroupBy Group the data by a set of dimensions. Can specify one time dimension. This property adds a `GROUP BY` clause to the query so all the normal behaviors when quering InfluxDB with a `GROUP BY` apply. Use group by time when your period is longer than your group by time interval. Example: ```js batch |query(...) .period(1m) .every(1m) .groupBy(time(10s), 'tag1', 'tag2')) .align() ``` A group by time offset is also possible. Example: ```js batch |query(...) .period(1m) .every(1m) .groupBy(time(10s, -5s), 'tag1', 'tag2')) .align() .offset(5s) ``` It is recommended to use [QueryNode.Align](/kapacitor/v1.5/nodes/query_node/#align) and [QueryNode.Offset](/kapacitor/v1.5/nodes/query_node/#offset) in conjunction with group by time dimensions so that the time bounds match up with the group by intervals. To automatically align the group by intervals to the start of the query time, use [QueryNode.AlignGroup.](/kapacitor/v1.5/nodes/query_node/#aligngroup) This is useful in more complex situations, such as when the groupBy time period is longer than the query frequency. Example: ```js batch |query(...) .period(5m) .every(30s) .groupBy(time(1m), 'tag1', 'tag2') .align() .alignGroup() ``` For the above example, without [QueryNode.AlignGroup,](/kapacitor/v1.5/nodes/query_node/#aligngroup) every other query issued by Kapacitor (at :30 past the minute) will align to :00 seconds instead of the desired :30 seconds, which would create 6 group by intervals instead of 5, the first and last of which would only have 30 seconds of data instead of a full minute. If the group by time offset (i.e. time(t, offset)) is used in conjunction with [QueryNode.AlignGroup,](/kapacitor/v1.5/nodes/query_node/#aligngroup) the alignment will occur first, and will be offset the specified amount after. NOTE: Since [QueryNode.Offset](/kapacitor/v1.5/nodes/query_node/#offset) is inherently a negative property the second "offset" argument to the "time" function is negative to match. ```js query.groupBy(d ...interface{}) ``` ### GroupByMeasurement If set will include the measurement name in the group ID. Along with any other group by dimensions. Example: ```js batch |query('SELECT sum("value") FROM "telegraf"."autogen"./process_.*/') .groupByMeasurement() .groupBy('host') ``` The above example selects data from several measurements matching `/process_.*/ and then each point is grouped by the host tag and measurement name. Thus keeping measurements in their own groups. ```js query.groupByMeasurement() ``` ### Offset How far back in time to query from the current time For example an Offset of 2 hours and an Every of 5m, Kapacitor will query InfluxDB every 5 minutes for the window of data 2 hours ago. This applies to Cron schedules as well. If the cron specifies to run every Sunday at 1 AM and the Offset is 1 hour. Then at 1 AM on Sunday the data from 12 AM will be queried. ```js query.offset(value time.Duration) ``` ### Period The period or length of time that will be queried from InfluxDB ```js query.period(value time.Duration) ``` ### Quiet Suppress all error logging events from this node. ```js query.quiet() ``` ## Chaining Methods Chaining methods create a new node in the pipeline as a child of the calling node. They do not modify the calling node. Chaining methods are marked using the `|` operator. ### Alert Create an alert node, which can trigger alerts. ```js query|alert() ``` Returns: [AlertNode](/kapacitor/v1.5/nodes/alert_node/) ### Barrier Create a new Barrier node that emits a BarrierMessage periodically. One BarrierMessage will be emitted every period duration. ```js query|barrier() ``` Returns: [BarrierNode](/kapacitor/v1.5/nodes/barrier_node/) ### Bottom Select the bottom `num` points for `field` and sort by any extra tags or fields. ```js query|bottom(num int64, field string, fieldsAndTags ...string) ``` Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/) ### ChangeDetect Create a new node that only emits new points if different from the previous point. ```js query|changeDetect(field string) ``` Returns: [ChangeDetectNode](/kapacitor/v1.5/nodes/change_detect_node/) ### Combine Combine this node with itself. The data is combined on timestamp. ```js query|combine(expressions ...ast.LambdaNode) ``` Returns: [CombineNode](/kapacitor/v1.5/nodes/combine_node/) ### Count Count the number of points. ```js query|count(field string) ``` Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/) ### CumulativeSum Compute a cumulative sum of each point that is received. A point is emitted for every point collected. ```js query|cumulativeSum(field string) ``` Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/) ### Deadman Helper function for creating an alert on low throughput, a.k.a. deadman's switch. - Threshold: trigger alert if throughput drops below threshold in points/interval. - Interval: how often to check the throughput. - Expressions: optional list of expressions to also evaluate. Useful for time of day alerting. Example: ```js var data = batch |query()... // Trigger critical alert if the throughput drops below 100 points per 10s and checked every 10s. data |deadman(100.0, 10s) //Do normal processing of data data... ``` The above is equivalent to this example: ```js var data = batch |query()... // Trigger critical alert if the throughput drops below 100 points per 10s and checked every 10s. data |stats(10s) .align() |derivative('emitted') .unit(10s) .nonNegative() |alert() .id('node \'stream0\' in task \'{{ .TaskName }}\'') .message('{{ .ID }} is {{ if eq .Level "OK" }}alive{{ else }}dead{{ end }}: {{ index .Fields "emitted" | printf "%0.3f" }} points/10s.') .crit(lambda: "emitted" <= 100.0) //Do normal processing of data data... ``` The `id` and `message` alert properties can be configured globally via the 'deadman' configuration section. Since the [AlertNode](/kapacitor/v1.5/nodes/alert_node/) is the last piece it can be further modified as usual. Example: ```js var data = batch |query()... // Trigger critical alert if the throughput drops below 100 points per 10s and checked every 10s. data |deadman(100.0, 10s) .slack() .channel('#dead_tasks') //Do normal processing of data data... ``` You can specify additional lambda expressions to further constrain when the deadman's switch is triggered. Example: ```js var data = batch |query()... // Trigger critical alert if the throughput drops below 100 points per 10s and checked every 10s. // Only trigger the alert if the time of day is between 8am-5pm. data |deadman(100.0, 10s, lambda: hour("time") >= 8 AND hour("time") <= 17) //Do normal processing of data data... ``` ```js query|deadman(threshold float64, interval time.Duration, expr ...ast.LambdaNode) ``` Returns: [AlertNode](/kapacitor/v1.5/nodes/alert_node/) ### Default Create a node that can set defaults for missing tags or fields. ```js query|default() ``` Returns: [DefaultNode](/kapacitor/v1.5/nodes/default_node/) ### Delete Create a node that can delete tags or fields. ```js query|delete() ``` Returns: [DeleteNode](/kapacitor/v1.5/nodes/delete_node/) ### Derivative Create a new node that computes the derivative of adjacent points. ```js query|derivative(field string) ``` Returns: [DerivativeNode](/kapacitor/v1.5/nodes/derivative_node/) ### Difference Compute the difference between points independent of elapsed time. ```js query|difference(field string) ``` Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/) ### Distinct Produce batch of only the distinct points. ```js query|distinct(field string) ``` Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/) ### Ec2Autoscale Create a node that can trigger autoscale events for a ec2 autoscalegroup. ```js query|ec2Autoscale() ``` Returns: [Ec2AutoscaleNode](/kapacitor/v1.5/nodes/ec2_autoscale_node/) ### Elapsed Compute the elapsed time between points. ```js query|elapsed(field string, unit time.Duration) ``` Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/) ### Eval Create an eval node that will evaluate the given transformation function to each data point. A list of expressions may be provided and will be evaluated in the order they are given. The results are available to later expressions. ```js query|eval(expressions ...ast.LambdaNode) ``` Returns: [EvalNode](/kapacitor/v1.5/nodes/eval_node/) ### First Select the first point. ```js query|first(field string) ``` Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/) ### Flatten Flatten points with similar times into a single point. ```js query|flatten() ``` Returns: [FlattenNode](/kapacitor/v1.5/nodes/flatten_node/) ### HoltWinters Compute the Holt-Winters (/{{< latest "influxdb" "v1" >}}/query_language/functions/#holt-winters) forecast of a data set. ```js query|holtWinters(field string, h int64, m int64, interval time.Duration) ``` Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/) ### HoltWintersWithFit Compute the Holt-Winters (/{{< latest "influxdb" "v1" >}}/query_language/functions/#holt-winters) forecast of a data set. This method also outputs all the points used to fit the data in addition to the forecasted data. ```js query|holtWintersWithFit(field string, h int64, m int64, interval time.Duration) ``` Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/) ### HttpOut Create an HTTP output node that caches the most recent data it has received. The cached data is available at the given endpoint. The endpoint is the relative path from the API endpoint of the running task. For example, if the task endpoint is at `/kapacitor/v1/tasks/` and endpoint is `top10`, then the data can be requested from `/kapacitor/v1/tasks//top10`. ```js query|httpOut(endpoint string) ``` Returns: [HTTPOutNode](/kapacitor/v1.5/nodes/http_out_node/) ### HttpPost Creates an HTTP Post node that POSTS received data to the provided HTTP endpoint. HttpPost expects 0 or 1 arguments. If 0 arguments are provided, you must specify an endpoint property method. ```js query|httpPost(url ...string) ``` Returns: [HTTPPostNode](/kapacitor/v1.5/nodes/http_post_node/) ### InfluxDBOut Create an influxdb output node that will store the incoming data into InfluxDB. ```js query|influxDBOut() ``` Returns: [InfluxDBOutNode](/kapacitor/v1.5/nodes/influx_d_b_out_node/) ### Join Join this node with other nodes. The data is joined on timestamp. ```js query|join(others ...Node) ``` Returns: [JoinNode](/kapacitor/v1.5/nodes/join_node/) ### K8sAutoscale Create a node that can trigger autoscale events for a kubernetes cluster. ```js query|k8sAutoscale() ``` Returns: [K8sAutoscaleNode](/kapacitor/v1.5/nodes/k8s_autoscale_node/) ### KapacitorLoopback Create an kapacitor loopback node that will send data back into Kapacitor as a stream. ```js query|kapacitorLoopback() ``` Returns: [KapacitorLoopbackNode](/kapacitor/v1.5/nodes/kapacitor_loopback_node/) ### Last Select the last point. ```js query|last(field string) ``` Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/) ### Log Create a node that logs all data it receives. ```js query|log() ``` Returns: [LogNode](/kapacitor/v1.5/nodes/log_node/) ### Max Select the maximum point. ```js query|max(field string) ``` Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/) ### Mean Compute the mean of the data. ```js query|mean(field string) ``` Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/) ### Median Compute the median of the data. > **Note:** This method is not a selector. If you want the median point, use `.percentile(field, 50.0)`. ```js query|median(field string) ``` Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/) ### Min Select the minimum point. ```js query|min(field string) ``` Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/) ### Mode Compute the mode of the data. ```js query|mode(field string) ``` Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/) ### MovingAverage Compute a moving average of the last window points. No points are emitted until the window is full. ```js query|movingAverage(field string, window int64) ``` Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/) ### Percentile Select a point at the given percentile. This is a selector function, no interpolation between points is performed. ```js query|percentile(field string, percentile float64) ``` Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/) ### Sample Create a new node that samples the incoming points or batches. One point will be emitted every count or duration specified. ```js query|sample(rate interface{}) ``` Returns: [SampleNode](/kapacitor/v1.5/nodes/sample_node/) ### Shift Create a new node that shifts the incoming points or batches in time. ```js query|shift(shift time.Duration) ``` Returns: [ShiftNode](/kapacitor/v1.5/nodes/shift_node/) ### Sideload Create a node that can load data from external sources. ```js query|sideload() ``` Returns: [SideloadNode](/kapacitor/v1.5/nodes/sideload_node/) ### Spread Compute the difference between `min` and `max` points. ```js query|spread(field string) ``` Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/) ### StateCount Create a node that tracks number of consecutive points in a given state. ```js query|stateCount(expression ast.LambdaNode) ``` Returns: [StateCountNode](/kapacitor/v1.5/nodes/state_count_node/) ### StateDuration Create a node that tracks duration in a given state. ```js query|stateDuration(expression ast.LambdaNode) ``` Returns: [StateDurationNode](/kapacitor/v1.5/nodes/state_duration_node/) ### Stats Create a new stream of data that contains the internal statistics of the node. The interval represents how often to emit the statistics based on real time. This means the interval time is independent of the times of the data points the source node is receiving. ```js query|stats(interval time.Duration) ``` Returns: [StatsNode](/kapacitor/v1.5/nodes/stats_node/) ### Stddev Compute the standard deviation. ```js query|stddev(field string) ``` Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/) ### Sum Compute the sum of all values. ```js query|sum(field string) ``` Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/) ### SwarmAutoscale Create a node that can trigger autoscale events for a Docker swarm cluster. ```js query|swarmAutoscale() ``` Returns: [SwarmAutoscaleNode](/kapacitor/v1.5/nodes/swarm_autoscale_node/) ### Top Select the top `num` points for `field` and sort by any extra tags or fields. ```js query|top(num int64, field string, fieldsAndTags ...string) ``` Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/) ### Union Perform the union of this node and all other given nodes. ```js query|union(node ...Node) ``` Returns: [UnionNode](/kapacitor/v1.5/nodes/union_node/) ### Where Create a new node that filters the data stream by a given expression. ```js query|where(expression ast.LambdaNode) ``` Returns: [WhereNode](/kapacitor/v1.5/nodes/where_node/) ### Window Create a new node that windows the stream by time. NOTE: Window can only be applied to stream edges. ```js query|window() ``` Returns: [WindowNode](/kapacitor/v1.5/nodes/window_node/)