Splunk® Data Stream Processor

Function Reference

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DSP 1.2.0 is impacted by the CVE-2021-44228 and CVE-2021-45046 security vulnerabilities from Apache Log4j. To fix these vulnerabilities, you must upgrade to DSP 1.2.4. See Upgrade the Splunk Data Stream Processor to 1.2.4 for upgrade instructions.

On October 30, 2022, all 1.2.x versions of the Splunk Data Stream Processor will reach its end of support date. See the Splunk Software Support Policy for details.
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MV Expand

This topic describes how to use the function in the .

Description

Use the mvexpand function to expand the values in a multivalue field into separate events, one event for each value in the multivalue field.

Function Input/Output

Function Input
collection<record<R>>
This function takes in collections of records with schema R.
Function Output
collection<record<S>>
This function outputs the same collection of records but with a different schema S.

Syntax

mvexpand
[limit=<int>]
<field>

Required arguments

field
Syntax: <field>
Description: The name of the multivalue field that you want to expand. You can only specify one field to expand.

Optional arguments

limit
Syntax: <int>
Description: Specifies the number of values to expand in the multivalue field array. If there are any remaining values in the array those values are dropped. If omitted limit defaults to 0, which means there is no limit and all values are expanded.
Example in Canvas View: 5

Usage

Suppose your streaming data has fields a, b, and c. Each field has the following corresponding values:

Field a Field b Field c
1 x V1, V2, V3
2 y V4, V5

Pass in the c field to the mvexpand function:

Field Description Example
Field This is the name of the multivalue field. c
Limit This is the limit you want to set. 0

This example takes each row from the incoming streaming data and then creates a new row with each value in the c field. The other fields will have duplicate values, while the c field will have each value from the multivalue field in a separate row.

Field a Field b Field c
1 x V1
1 x V2
1 x V3
2 y V4
2 y V5

SPL2 example

Examples of common use cases follow. The following examples in this section assume that you are in the SPL View.

When working in the SPL View you can write the function by providing the arguments in the exact order shown in each use case.

Create a new record for each value of the multivalue field, "foo".

... | mvexpand foo |...

Limit the number of values from the multivalue field to expand

Create new records for the first 5 values of multivalue field, "foo". Any remaining values are dropped.

...| mvexpand limit=5 foo |...
Last modified on 17 March, 2022
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This documentation applies to the following versions of Splunk® Data Stream Processor: 1.1.0, 1.2.0, 1.2.1-patch02, 1.2.1, 1.2.2-patch02, 1.2.4, 1.2.5, 1.3.0, 1.3.1, 1.4.0, 1.4.1, 1.4.2, 1.4.3


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