Maintenance tasks

It is highly recommended that the access node is configured to run a maintenance job that regularly "heals" any non-completed distributed transactions. A distributed transaction ensures atomic execution across multiple data nodes and can remain in a non-completed state in case a data node reboots or experiences temporary issues. The access node keeps a log of distributed transactions so that nodes that haven't yet completed their part of the distributed transaction can later complete it at the access node's request. The log requires regular cleanup to "garbage collect" transactions that have completed and heal those that haven't. The maintenance job can be run as a user-defined action (custom job):

CREATE OR REPLACE PROCEDURE data_node_maintenance(job_id int, config jsonb)
LANGUAGE SQL AS
$$
    SELECT _timescaledb_internal.remote_txn_heal_data_node(fs.oid)
    FROM pg_foreign_server fs, pg_foreign_data_wrapper fdw
    WHERE fs.srvfdw = fdw.oid
    AND fdw.fdwname = 'timescaledb_fdw';
$$;

SELECT add_job('data_node_maintenance', '5m');

It is also possible to schedule this job to run from outside the database, e.g, via a CRON job. Note that the job must be scheduled separately for each database that contains distributed hypertables.

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