title: Airflow - Export PostgreSQL table using COPY
body: <p>In airflow we have Postgres to GCS and S3 operators, these all are using SQL query to fetch the results and export it to the target.</p>
  <p>But for large tables, <code>COPY</code> method would be preferred. Is there any such operators in Airflow to export the data via COPY and having options to mention the where condition?</p>