Data retention

Data retention is the period for which individual click events are kept before storage removes them. That makes it different from the depth a plan allows you to look back over, and confusing the two is expensive. A commercial limit hides older rows from the report while they sit intact in the table, so a larger plan reveals them again. Retention that has elapsed reveals nothing, because there is nothing left to reveal.

Two details decide whether a retention setting is honest. Deletion has to be carried out by the storage layer on the rows themselves rather than by a filter applied while reading, and the value has to travel with each row. A click written while the setting stood at thirty days is deleted after thirty days even if the workspace later raises the figure to two years: the rule in force when the row was written is the one that runs, and nothing rewrites history in either direction.

Aggregated counts, which identify nobody, normally outlive the detailed events behind them.