Batch Merger


This stage generates a group tag for each record in the current batch based on the specified condition. The records are then merged with the same tag and output in a single record. The function of this stage includes:

  • Supporting 2 methods for generating group keys: by record field value or EL expression.

Configuration

The configuration tabs for this stage are General, Basic, Input/Output, and Group Key.

General

Name

Required?

Description

Name

Yes

The name of the stage.

Description

No

The description of the stage.

Stage Library

Yes

The streaming operator library to which the stage belongs.

Required Fields

No

The fields that the data records must contain. If the specified fields are not included, the record will be filtered out.

Preconditions

No

The conditions that must be satisfied by the data records. Records that do not meet the conditions will be filtered out. For example, ${record:value('/value') > 0}. For the syntax of EL expressions, see Expression Language.

On Record Error

Yes

The processing method for error data.

  • Discard: Error data will be discarded and ignored

  • Send to Error: Error messages will be reported

  • Stop Pipeline: The pipeline will be stopped

Basic

Name

Required?

Description

Quality Filter

No

Filter the data according to the data quality. Only records that meet the quality conditions will be processed by this stage.

Input/Output

Name

Required?

Description

Input Point

Yes

Specify the input point of the records, using the format {modelId}::{pointId}.

Output Point

Yes

Specify the output point of the records, using the format {modelId}::{pointId}.

Group Key

Name

Required?

Description

Key Generate Method

Yes

Select the method for generating group tags. The options are By Record Field Value and By EL Expression.

Fields

No

When By Record Field Value is selected, select or specify the field name.

EL Expression

No

When By EL Expression is selected, type the expression for generating the group keys.

Output Results

The output results of this stage are included in the attr struct. The description of the fields are as follows:

Name

Data Type

Description

crossBatch

Map

The collection of records with the same group key.

Output Example

../../../_images/cross_batch_merger1.png