Recently I tried running my RoR applications on Oracle.

I noticed that when I ran rake db:migrate it would hang. Specifically it would hang during the schema dump phase.

E:\work\sandbox>rake db:migrate --trace -v
(in E:/work/sandbox)
** Invoke db:migrate (first_time)
** Invoke environment (first_time)
** Execute environment
** Execute db:migrate
** Invoke db:schema:dump (first_time)
** Invoke environment
** Execute db:schema:dump

I realized later that this was because the schema dump phase is very slow and the database I was using had many other tables from other applications. When I left it running it finally completed after 10 minutes.

You can see the slow progress of the schema dump phase by tailing schema.rb in the db directory.