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.
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