title: Move and transform data between databases using Airflow
body: <p>Using airflow, I extract data from a MySQL database, transform it with python and load it into a Redshift cluster.</p>
  
  <p>Currently I use 3 airflow tasks : they pass the data by writing CSV on local disk.</p>
  
  <p>How could I do this without writing to disk ?
  Should I write one big task in python ? ( That would lower visibility )  </p>
  
  <p>Edit: this is a question about Airflow, and best practice for choosing the granularity of tasks and how to pass data between them.
  It is not a general question about data migration or ETL. In this question ETL is only used as an exemple of workload for airflow tasks.</p>