(Engine-Level Function)
| Description: | Conditionally deletes full sequences of records from the data store identified by the ConnectionHandle |
| Warning: |
This function should be used only by advanced programmers. The functions, WriteHistory and GetTagHistory and GetLog are recommended for most uses. |
| Returns: | An array of SequenceID values, indicating which sequences were deleted |
Usage:  |
Script Only. |
| Threaded: | Yes |
| Related to: | HistorianConnect | HistorianGetData | HistorianGetInfo | HistorianReadRecords | HistorianWriteRecords |
| Format: |
HistorianDeleteRecords (ConnectionHandle, TagName, Schema, MinGroupValue, NumRecordsToKeep) |
| Parameters: |
| ConnectionHandle |
| As returned by an HistorianConnect call. |
| TagName |
| A text string identifying the tag whose records are to be deleted. |
| Schema |
| This is a textual representation of a schema structure. |
| MinGroupValue |
| All sequences with a Group Value (the last 4 bytes of the 12-byte SequenceID) less than this value will be deleted, provided that the NumRecordsToKeep condition is also met. |
| NumRecordsToKeep |
| A numeric expression, specifying a minimum number of records that are to be kept for the tag. |
| Comments: |
This function will delete as many entire sequences from storage for a tag as it can so that at least NumRecordsToKeep records are kept, and only sequences with a lower group value than MinGroupValue are deleted. While considered to be threaded, this function has no lifetime after it passes the records to another thread for deletion. |
Example:
No example provided. This function is not recommended for most use.
