Simplified Time Window Aggregator¶

This stage aggregates records arriving in a specified time window and output the sum of all records. The arrival of a record will trigger the calculation. This stage is used for calculating electric energy data. This stage cannot guarantee idempotence of the calculation results due to failure retries caused by any reasons, such as cluster node exceptions.

Configuration¶

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

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 https://docs.streamsets.com/portal/datacollector/latest/help/datacollector/UserGuide/Expression_Language/ExpressionLanguage_overview.html>`__.
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}. For the same configuration row, the modelId must be the same, and the input point and the output point must be different.
Aggregate Window	Yes	Select the duration of the time window, that is, the time interval for the aggregated result output.
Output Point	Yes	Specify the output point of records, using the format {modelId}::{pointId}. For a same configuration row, the modelId must be the same, and the input point and the output point must be different.

CacheConfig¶

Name

Required?

Description

Cache Type

Yes

Select the storage type for cache data. Options are Redis and Local storage.

Redis: The advantage is that the cached data will not be lost after the stream processing pipeline is paused, restarted, or retried. The disadvantage is that the data processing speed is slow and that it is sensitive to network performance. It is recommended that the network delay should be less than 1ms. Otherwise, the data processing performance will be affected.
Local: The advantage is that the data processing speed is fast. The disadvantage is that the cached data will be lost after the stream processing pipeline is paused, restarted, or retried.

Output Results¶

The aggregated output results of this stage are included in the attr struct.

Output Example¶

../../../_images/delta_down_sampler_result1.png