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 |...