What is a hung PDT regenerator?

[adina_katz]

Knowledge Drop

Last tested: Oct 15, 2020
 

The PDT Regenerator is the process responsible for checking sql triggers and rebuilding derived tables that are persisted using a sql trigger (either via a datagroup or a sql_trigger_value).

The regenerator is considered hung when:
1. It reports that it is executing sql for a PDT build/ trigger check and that sql is not executing on the database.
2. The regenerator process has not begun since the previous regenerator process has completed within the timeframe dictated by the "PDT And Datagroup Maintenance Schedule".

If you suspect a hung regenerator, see How to determine if the regenerator is hung.

Why do hung regenerators happen?

The source of a hung regenerator is usually difficult to track down, as it typically involves something on the network or database side interrupting the regeneration process. We have seen a number of reports of hung regenerators coinciding with Redshift database maintenance, including a mass maintenance Redshift performed that caused a critical because of the large number of customers whose regenerators were hung.

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