python & postgresql: reliably check for updates in a specific table
You can use notifications in postgresql:
import psycopg2from psycopg2.extensions import ISOLATION_LEVEL_AUTOCOMMITimport selectdef dblisten(dsn): connection = psycopg2.connect(dsn) connection.set_isolation_level(ISOLATION_LEVEL_AUTOCOMMIT) cur = connection.cursor() cur.execute("LISTEN new_id;") while True: select.select([connection],[],[]) connection.poll() events = [] while connection.notifies: notify = connection.notifies.pop().payload do_something(notify)and install a trigger for each update:
CREATE OR REPLACE FUNCTION notify_id_trigger() RETURNS trigger AS $$BEGIN PERFORM pg_notify('new_id', NEW.ID); RETURN new;END;$$ LANGUAGE plpgsql;CREATE TRIGGER data_modified AFTER insert or update on data_table for each row execute procedure notify_id_trigger();")