Introduction

Christian Simms found a way to use sqlalchemy-migrate with Oracle XE http://groups.google.de/group/migrate-users/browse_thread/thread/a432b3cbe564b2b5

Details

It looks like the problem is that the default max number of connections is too small in Oracle XE -- causing the ORA-12516 error when running unit tests. Luckily, it is pretty easy to fix, I'll explain how to below.

Once you connect to Oracle under a system account using sqlplus (e.g., sqlplus system/password@xe), run these two commands:

   show parameter processes
   show parameter sessions

The output is a little confusing, since the lines are usually split in the console window. For my system for instance, the setting "processes" was 40. But about half of those are already reserved for system processes, so you actually have a lot less available. Anyway, I bumped mine up by running these 2 commands in sqlplus:

  alter system set processes=100 scope=spfile;
  alter system set sessions = 115 scope = spfile;

That sets the max number of processes to 100 and sessions to 115. (I grabbed these values from http://clemensblog.blogspot.com/2006/04/oracle-bpel-xe-part-2.html).

You need to restart Oracle for these changes to take effect (these value changes will persist), such as: sudo /etc/init.d/oracle-xe restart

Cheers, Christian