What parameter sets the maximum amount of time that a persistent derived table may be used before it is regenerated?

The parameter that sets the maximum amount of time a persistent derived table (PDT) can be used before it must be regenerated is "persist_for." This setting defines a specific time period during which the results of the derived table will remain valid and available for queries. By establishing a limit on how long the data can persist, it ensures that users are not working with outdated or stale data, thereby maintaining the accuracy and relevancy of the information being accessed. The "persist_for" parameter is crucial for managing resources and ensuring optimal performance within Looker because it automates the regeneration process as needed based on the defined timeframe, thus balancing data freshness with performance.