Sliding Time Window Aggregator


This stage aggregates the data of a single point by the sliding time window. The settings for this stage are as per the below.

  • Window type: Sliding window.

  • Supported aggregators: max/min/avg/count/sum/first/last.

  • 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, ExtraConfig, 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}.

Fixed Window Size

Yes

Specify the duration for the fixed time window, which is equal to the step length of the sliding window.

Fixed Window Unit

Yes

Select the unit for the fixed time window.

Sliding Window Size

Yes

Specify the step length of the sliding window.

Sliding Window Unit

Yes

Select the unit for the sliding window.

Aggregator Policy

Yes

Select the aggregator for data aggregation: max/min/avg/count/sum/first/last.

Output Point

Yes

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

ExtraConfig

Name

Required?

Description

Output Data Type

Yes

Select the output data type. Options are Double and From TSL Model Service.

  • Double: You can select this option if the output points are all for intermediate calculation results (the output points are not defined on the model), or the data type of all the output points is Double.

  • From TSL Model Service: You must select this option if the output points are defined on the model and the data type of the points is not Double. Otherwise, the output data cannot be stored in TSDB correctly.

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

Name

Data Type

Description

lastOutput

Integer/Double/Float

The last output of the point (NaN for no output).

calMode

String

The output mode, which is the final output.

calType

String

The selected aggregator: max/min/avg/count/sum/first/last.

calDetail

Map

The calculation details. For example, when calType=avg, output the sum and count value of value and lastValue.

Output Example

../../../_images/sliding_window_aggregator3.png