---
title: CombineNode (Kapacitor TICKscript node)
description: CombineNode combines data from a single node with itself. Points with the same time are grouped and then combinations are created. The size of the combinations is defined by how many expressions are given.
note: Auto generated by tickdoc
menu:
kapacitor_1_4:
name: CombineNode
identifier: combine_node
weight: 40
parent: TICKscript nodes
---
### Constructor
| Chaining Method | Description |
|:---------|:---------|
| **[combine](#descr) ( `expressions` `...ast.LambdaNode`)** | Combine this node with itself. The data is combined on timestamp. |
### Property Methods
| Setters | Description |
|:---|:---|
| **[as](#as) ( `names` `...string`)** | Prefix names for all fields from the respective nodes. Each field from the parent nodes will be prefixed with the provided name and a '.'. See the example above. |
| **[delimiter](#delimiter) ( `value` `string`)** | The delimiter between the As names and existing field an tag keys. Can be the empty string, but you are responsible for ensuring conflicts are not possible if you use the empty string. |
| **[max](#max) ( `value` `int64`)** | Maximum number of possible combinations. Since the number of possible combinations can grow very rapidly you can set a maximum number of combinations allowed. If the max is crossed, an error is logged and the combinations are not calculated. Default: 10,000 |
| **[tolerance](#tolerance) ( `value` `time.Duration`)** | The maximum duration of time that two incoming points can be apart and still be considered to be equal in time. The joined data point's time will be rounded to the nearest multiple of the tolerance duration. |
### Chaining Methods
[Alert](/kapacitor/v1.4/nodes/combine_node/#alert), [Barrier](/kapacitor/v1.4/nodes/combine_node/#barrier), [Bottom](/kapacitor/v1.4/nodes/combine_node/#bottom), [Combine](/kapacitor/v1.4/nodes/combine_node/#combine), [Count](/kapacitor/v1.4/nodes/combine_node/#count), [CumulativeSum](/kapacitor/v1.4/nodes/combine_node/#cumulativesum), [Deadman](/kapacitor/v1.4/nodes/combine_node/#deadman), [Default](/kapacitor/v1.4/nodes/combine_node/#default), [Delete](/kapacitor/v1.4/nodes/combine_node/#delete), [Derivative](/kapacitor/v1.4/nodes/combine_node/#derivative), [Difference](/kapacitor/v1.4/nodes/combine_node/#difference), [Distinct](/kapacitor/v1.4/nodes/combine_node/#distinct), [Ec2Autoscale](/kapacitor/v1.4/nodes/combine_node/#ec2autoscale), [Elapsed](/kapacitor/v1.4/nodes/combine_node/#elapsed), [Eval](/kapacitor/v1.4/nodes/combine_node/#eval), [First](/kapacitor/v1.4/nodes/combine_node/#first), [Flatten](/kapacitor/v1.4/nodes/combine_node/#flatten), [GroupBy](/kapacitor/v1.4/nodes/combine_node/#groupby), [HoltWinters](/kapacitor/v1.4/nodes/combine_node/#holtwinters), [HoltWintersWithFit](/kapacitor/v1.4/nodes/combine_node/#holtwinterswithfit), [HttpOut](/kapacitor/v1.4/nodes/combine_node/#httpout), [HttpPost](/kapacitor/v1.4/nodes/combine_node/#httppost), [InfluxDBOut](/kapacitor/v1.4/nodes/combine_node/#influxdbout), [Join](/kapacitor/v1.4/nodes/combine_node/#join), [K8sAutoscale](/kapacitor/v1.4/nodes/combine_node/#k8sautoscale), [KapacitorLoopback](/kapacitor/v1.4/nodes/combine_node/#kapacitorloopback), [Last](/kapacitor/v1.4/nodes/combine_node/#last), [Log](/kapacitor/v1.4/nodes/combine_node/#log), [Mean](/kapacitor/v1.4/nodes/combine_node/#mean), [Median](/kapacitor/v1.4/nodes/combine_node/#median), [Min](/kapacitor/v1.4/nodes/combine_node/#min), [Mode](/kapacitor/v1.4/nodes/combine_node/#mode), [MovingAverage](/kapacitor/v1.4/nodes/combine_node/#movingaverage), [Percentile](/kapacitor/v1.4/nodes/combine_node/#percentile), [Sample](/kapacitor/v1.4/nodes/combine_node/#sample), [Shift](/kapacitor/v1.4/nodes/combine_node/#shift), [Sideload](/kapacitor/v1.4/nodes/combine_node/#sideload), [Spread](/kapacitor/v1.4/nodes/combine_node/#spread), [StateCount](/kapacitor/v1.4/nodes/combine_node/#statecount), [StateDuration](/kapacitor/v1.4/nodes/combine_node/#stateduration), [Stats](/kapacitor/v1.4/nodes/combine_node/#stats), [Stddev](/kapacitor/v1.4/nodes/combine_node/#stddev), [Sum](/kapacitor/v1.4/nodes/combine_node/#sum), [SwarmAutoscale](/kapacitor/v1.4/nodes/combine_node/#swarmautoscale), [Top](/kapacitor/v1.4/nodes/combine_node/#top), [Union](/kapacitor/v1.4/nodes/combine_node/#union), [Where](/kapacitor/v1.4/nodes/combine_node/#where), [Window](/kapacitor/v1.4/nodes/combine_node/#window)
### Description
Combine the data from a single node with itself.
Points with the same time are grouped and then combinations are created.
The size of the combinations is defined by how many expressions are given.
Combinations are order independent and never include the same point multiple times.
Example:
```javascript
stream
|from()
.measurement('request_latency')
|combine(lambda: "service" == 'login', lambda: TRUE)
.as('login', 'other')
// points that are within 1 second are considered the same time.
.tolerance(1s)
// delimiter for new field and tag names
.delimiter('.')
// Change group by to be new other.service tag
|groupBy('other.service')
// Both the "value" fields from each data point have been prefixed
// with the respective names 'login' and 'other'.
|eval(lambda: "login.value" / "other.value")
.as('ratio')
...
```
In the example above, the data points for the `login` service are combined with the data points from all other services.
Example:
```javascript
|combine(lambda: TRUE, lambda: TRUE)
.as('login', 'other')
```
In the example above, all combination pairs are created.
Example:
```javascript
|combine(lambda: TRUE, lambda: TRUE, lambda: TRUE)
.as('login', 'other', 'another')
```
In the example above, all combinations triples are created.
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.
### As
Prefix names for all fields from the respective nodes.
Each field from the parent nodes will be prefixed with the provided name and a `.`.
See the example above.
The names cannot have a dot `.` character.
```javascript
combine.as(names ...string)
```
### Delimiter
The delimiter between the As names and existing field an tag keys.
Can be the empty string, but you are responsible for ensuring conflicts are not possible if you use the empty string.
```javascript
combine.delimiter(value string)
```
### Max
Maximum number of possible combinations.
Since the number of possible combinations can grow very rapidly,
you can set a maximum number of combinations allowed.
If the max is exceeded, an error is logged and the combinations are not calculated.
Default: 10,000
```javascript
combine.max(value int64)
```
### Tolerance
The maximum duration of time that two incoming points
can be apart and still be considered to be equal in time.
The joined data point's time will be rounded to the nearest
multiple of the tolerance duration.
```javascript
combine.tolerance(value time.Duration)
```
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.
```javascript
combine|alert()
```
Returns: [AlertNode](/kapacitor/v1.4/nodes/alert_node/)
### Barrier
Create a new Barrier node that emits a BarrierMessage periodically.
One Barrier message will be emitted every period duration.
```javascript
combine|barrier()
```
Returns: [BarrierNode](/kapacitor/v1.4/nodes/barrier_node/)
### Bottom
Select the bottom `num` points for `field` and sort by any extra tags or fields.
```javascript
combine|bottom(num int64, field string, fieldsAndTags ...string)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/nodes/influx_q_l_node/)
### Combine
Combine this node with itself. The data is combined on timestamp.
```javascript
combine|combine(expressions ...ast.LambdaNode)
```
Returns: [CombineNode](/kapacitor/v1.4/nodes/combine_node/)
### Count
Count the number of points.
```javascript
combine|count(field string)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/nodes/influx_q_l_node/)
### CumulativeSum
Compute a cumulative sum of each point that is received.
A point is emitted for every point collected.
```javascript
combine|cumulativeSum(field string)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/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:
```javascript
var data = stream
|from()...
// 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:
```javascript
var data = stream
|from()...
// 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/v1.4/nodes/alert_node/) is the last piece it can be further modified as usual.
Example:
```javascript
var data = stream
|from()...
// 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:
```javascript
var data = stream
|from()...
// 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...
```
```javascript
combine|deadman(threshold float64, interval time.Duration, expr ...ast.LambdaNode)
```
Returns: [AlertNode](/kapacitor/v1.4/nodes/alert_node/)
### Default
Create a node that can set defaults for missing tags or fields.
```javascript
combine|default()
```
Returns: [DefaultNode](/kapacitor/v1.4/nodes/default_node/)
### Delete
Create a node that can delete tags or fields.
```javascript
combine|delete()
```
Returns: [DeleteNode](/kapacitor/v1.4/nodes/delete_node/)
### Derivative
Create a node that computes the derivative of adjacent points.
```javascript
combine|derivative(field string)
```
Returns: [DerivativeNode](/kapacitor/v1.4/nodes/derivative_node/)
### Difference
Compute the difference between points independent of elapsed time.
```javascript
combine|difference(field string)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/nodes/influx_q_l_node/)
### Distinct
Produce batch of only the distinct points.
```javascript
combine|distinct(field string)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/nodes/influx_q_l_node/)
### Ec2Autoscale
Create a node that can trigger autoscale events for a ec2 autoscalegroup.
```javascript
combine|ec2Autoscale()
```
Returns: [Ec2AutoscaleNode](/kapacitor/v1.4/nodes/ec2_autoscale_node/)
### Elapsed
Compute the elapsed time between points.
```javascript
combine|elapsed(field string, unit time.Duration)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/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.
```javascript
combine|eval(expressions ...ast.LambdaNode)
```
Returns: [EvalNode](/kapacitor/v1.4/nodes/eval_node/)
### First
Select the first point.
```javascript
combine|first(field string)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/nodes/influx_q_l_node/)
### Flatten
Flatten points with similar times into a single point.
```javascript
combine|flatten()
```
Returns: [FlattenNode](/kapacitor/v1.4/nodes/flatten_node/)
### GroupBy
Group the data by a set of tags.
Can pass literal * to group by all dimensions.
Example:
```javascript
|groupBy(*)
```
```javascript
combine|groupBy(tag ...interface{})
```
Returns: [GroupByNode](/kapacitor/v1.4/nodes/group_by_node/)
### HoltWinters
Compute the Holt-Winters (/{{< latest "influxdb" "v1" >}}/query_language/functions/#holt-winters) forecast of a data set.
```javascript
combine|holtWinters(field string, h int64, m int64, interval time.Duration)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/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.
```javascript
combine|holtWintersWithFit(field string, h int64, m int64, interval time.Duration)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/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`.
```javascript
combine|httpOut(endpoint string)
```
Returns: [HTTPOutNode](/kapacitor/v1.4/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.
```javascript
combine|httpPost(url ...string)
```
Returns: [HTTPPostNode](/kapacitor/v1.4/nodes/http_post_node/)
### InfluxDBOut
Create an InfluxDB output node that will store the incoming data into InfluxDB.
```javascript
combine|influxDBOut()
```
Returns: [InfluxDBOutNode](/kapacitor/v1.4/nodes/influx_d_b_out_node/)
### Join
Join this node with other nodes. The data is joined on timestamp.
```javascript
combine|join(others ...Node)
```
Returns: [JoinNode](/kapacitor/v1.4/nodes/join_node/)
### K8sAutoscale
Create a node that can trigger autoscale events for a Kubernetes cluster.
```javascript
combine|k8sAutoscale()
```
Returns: [K8sAutoscaleNode](/kapacitor/v1.4/nodes/k8s_autoscale_node/)
### KapacitorLoopback
Create a Kapacitor loopback node that will send data back into Kapacitor as a stream.
```javascript
combine|kapacitorLoopback()
```
Returns: [KapacitorLoopbackNode](/kapacitor/v1.4/nodes/kapacitor_loopback_node/)
### Last
Select the last point.
```javascript
combine|last(field string)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/nodes/influx_q_l_node/)
### Log
Create a node that logs all data it receives.
```javascript
combine|log()
```
Returns: [LogNode](/kapacitor/v1.4/nodes/log_node/)
### Mean
Compute the mean of the data.
```javascript
combine|mean(field string)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/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)`.
```javascript
combine|median(field string)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/nodes/influx_q_l_node/)
### Min
Select the minimum point.
```javascript
combine|min(field string)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/nodes/influx_q_l_node/)
### Mode
Compute the mode of the data.
```javascript
combine|mode(field string)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/nodes/influx_q_l_node/)
### MovingAverage
Compute a moving average of the last window points.
No points are emitted until the window is full.
```javascript
combine|movingAverage(field string, window int64)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/nodes/influx_q_l_node/)
### Percentile
Select a point at the given percentile. This is a selector function, no interpolation between points is performed.
```javascript
combine|percentile(field string, percentile float64)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/nodes/influx_q_l_node/)
### Sample
Create a node that samples the incoming points or batches.
One point will be emitted every count or duration specified.
```javascript
combine|sample(rate interface{})
```
Returns: [SampleNode](/kapacitor/v1.4/nodes/sample_node/)
### Shift
Create a node that shifts the incoming points or batches in time.
```javascript
combine|shift(shift time.Duration)
```
Returns: [ShiftNode](/kapacitor/v1.4/nodes/shift_node/)
### Sideload
Create a node that can load data from external sources.
```javascript
combine|sideload()
```
Returns: [SideloadNode](/kapacitor/v1.4/nodes/sideload_node/)
### Spread
Compute the difference between `min` and `max` points.
```javascript
combine|spread(field string)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/nodes/influx_q_l_node/)
### StateCount
Create a node that tracks number of consecutive points in a given state.
```javascript
combine|stateCount(expression ast.LambdaNode)
```
Returns: [StateCountNode](/kapacitor/v1.4/nodes/state_count_node/)
### StateDuration
Create a node that tracks duration in a given state.
```javascript
combine|stateDuration(expression ast.LambdaNode)
```
Returns: [StateDurationNode](/kapacitor/v1.4/nodes/state_duration_node/)
### Stats
Create a 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.
```javascript
combine|stats(interval time.Duration)
```
Returns: [StatsNode](/kapacitor/v1.4/nodes/stats_node/)
### Stddev
Compute the standard deviation.
```javascript
combine|stddev(field string)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/nodes/influx_q_l_node/)
### Sum
Compute the sum of all values.
```javascript
combine|sum(field string)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/nodes/influx_q_l_node/)
### SwarmAutoscale
Create a node that can trigger autoscale events for a Docker swarm cluster.
```javascript
combine|swarmAutoscale()
```
Returns: [SwarmAutoscaleNode](/kapacitor/v1.4/nodes/swarm_autoscale_node/)
### Top
Select the top `num` points for `field` and sort by any extra tags or fields.
```javascript
combine|top(num int64, field string, fieldsAndTags ...string)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/nodes/influx_q_l_node/)
### Union
Perform the union of this node and all other given nodes.
```javascript
combine|union(node ...Node)
```
Returns: [UnionNode](/kapacitor/v1.4/nodes/union_node/)
### Where
Create a node that filters the data stream by a given expression.
```javascript
combine|where(expression ast.LambdaNode)
```
Returns: [WhereNode](/kapacitor/v1.4/nodes/where_node/)
### Window
Create a node that windows the stream by time.
NOTE: Window can only be applied to stream edges.
```javascript
combine|window()
```
Returns: [WindowNode](/kapacitor/v1.4/nodes/window_node/)