use luigi to Backup Postgresql, there has a problem, it's not flexible. but i still think that's workflow should be

luigiPgDemo.py

import luigi
import psycopg2

class QueryBackToTmp(luigi.Task):
    def run(self):
            conn_string = "host='ec2-54-zzz-xxx-yyy.cn-north-1.compute.amazonaws.com.cn' " \
				     "dbname='musicbrainz' " \
				     "user='postgres' " \
				     "password='password'"

            conn = psycopg2.connect(conn_string)
            cursor = conn.cursor()
            SQL = """ COPY (select artist.id as artist_id,
                        artist_credit.id as artist_credit_id ,
                        recording.id as recording_id ,
                        artist.gid as artist_gid,
                        recording.gid as recording_gid,
                        artist.name as artist_name,
                        artist_credit_name.artist as artist_credit_name_artist ,
                        artist_credit_name.name as artist_credit_name_name
                        from musicbrainz.artist,musicbrainz.artist_credit_name,musicbrainz.artist_credit,musicbrainz.recording
                        where artist.gid='a223958d-5c56-4b2c-a30a-87e357bc121b' limit 100)
                        TO '/home/tmp/tmp.csv' with csv;
                        """
            cursor.execute(SQL)
if __name__ == '__main__':
        luigi.run()