title: PostgreSQL ETL process on Heroku
body: <p>I've been given the task of writing an ETL (Extract, Transform, Load) process between a PostgreSQL 9.1 database hosted on Heroku (we can call it the Master) to another, application-purposed copy of the data that will be in another Heroku (Cedar Stack) hosted PostgreSQL database.  Our primary development stack is Python 2.7.2, Django 1.3.3 and PostgreSQL 9.1.  As many of you may know, the file system in Heroku is limited in what you can do, and I'm not sure if I completely understand what the rules are for the Ephemeral Filesystem.  </p>
  
  <p>So, I'm trying to figure out what my options are here.  The obvious one is that I can just write a Django management command and have two separate database connections (and a destination and source set of models) and pump the data over that way and handle the ETL in the process.  While effect, my initial tests shows this is a very slow approach.  Obviously, a faster approach would be to use PostreSQL COPY functionality.  But, normally if I was doing this I would be able to write it out to a file and then use psql to pull it in.  Any one done anything like this between two dedicated PostgreSQL databases on Heroku?  Any advice or tips will be appreciated.</p>