Process only the most recent values

Frequently you want to retrieve only rows that have been added to the table after the last scan was performed. Typically you select timestamps greater than the TS placeholder (the interface's cached value for time of last scan). This works nicely for single and group strategies. For distribution, however, the distributor tag is timestamped with current time, so the comparison does not work with the TS placeholder. If you are using the distribution approach and need to determine whether a row has been processed, you can use one of the approaches shown in the Learn about SQL examples for PI Interface for RDBMS section of this document.