Use a user-defined action to create a generic retention policy

TimescaleDB natively supports adding a data retention policy to a hypertable. If you want to add a generic data retention policy to all hypertables, you can write a user-defined action.

Using a user-defined action to create a generic retention policy

1. Create a procedure that drops chunks from any hypertable if they are older than the drop_after parameter. To get all hypertables, the timescaledb_information.hypertables table is queried.

   CREATE OR REPLACE PROCEDURE generic_retention (job_id int, config jsonb)
   LANGUAGE PLPGSQL
   AS $$
   DECLARE
     drop_after interval;
   BEGIN
     SELECT jsonb_object_field_text (config, 'drop_after')::interval
       INTO STRICT drop_after;
     IF drop_after IS NULL THEN
       RAISE EXCEPTION 'Config must have drop_after';
     END IF;
     PERFORM drop_chunks(
       format('%I.%I', hypertable_schema, hypertable_name),
       older_than => drop_after
     ) FROM timescaledb_information.hypertables;
   END
   $$;

2. Register the job to run daily. In the config, set drop_after to 12 months to drop chunks containing data older than 12 months.

   SELECT add_job('generic_retention','1d', config => '{"drop_after":"12 month"}');

note

You can further refine this policy by adding filters to your procedure. For example, add a WHERE clause to the PERFORM query to only drop chunks from particular hypertables.