Why does rake db:rollback rollback three steps?

问题

Normally when I do

$ rake db:rollback

it rolls back one migration. But now, repeatedly times, it has rollbacked 3 steps.

How come this behaviour?

I'm on Rails 3.2.13.

回答1:

You can specify the number of steps like this:

rake db:rollback STEP=3

The STEP parameter is actually an environment variable here. If, in your terminal, you run the command echo $STEP, does it return 3? If it does, you can execute export STEP=1 to get back to expected behaviour. If it happens again, try to find out where this environment variable is being set.

回答2:

bundle exec rails db:rollback STEP=3

来源：https://stackoverflow.com/questions/19805637/why-does-rake-dbrollback-rollback-three-steps