Last Changed Record Appender¶
This stage caches the latest data of each point and appends the latest data to each record.
For a single point of a single device:
- If there is no existing record of the point
- Cache the data of the point
- Append the cached data to the
/attr/lastChangedRecordAppender
field of the record
- If there is an existing record of the point
- Append the current cached data to the
/attr/lastChangedRecordAppender
field of the record - Compare the data with the cached data. If there are differences, refresh the cached data with the arrived data.
- Append the current cached data to the
Configuration¶
The configuration tabs for this stage are General, Basic, and Input/Output.
General¶
Name | Required? | Description |
---|---|---|
Name | Yes | The name of the stage. |
Description | No | The description of the stage. |
Stage Library | Yes | The streaming calculator 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. |
On Record Error | Yes | The processing method for error data.
|
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/Output | Yes | The last changed data is attached to each record. Specify the input points that hold the last changed data, and the output points that receive the output results. |
Input Point | Yes | Specify the input point that holds the last changed data, using the format {modelId}::{pointId}. |
Output Point | Yes | Specify the output point that receives the output results, using the format {modelId}::{pointId}. |
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 |
lastChangedRecordAppender | Map | The point attribute data object. |
lastChangedTs | Long | The timestamp of the last changed record. |
lastChangedValue | Object | The value of the last changed record. |
lastChangedRecord | Map | The complete information of the last changed record. |