rake db:rollback of a recent migration hangs - ruby-on-rails-3

Question

I have a rails app that I wrote originally in rail 3, and upgraded to rails 3.1.10 about a month ago. I just created a habtm association between stories and tags, along with the related db migrations.
class Story < ActiveRecord::Base
belongs_to :user
has_and_belongs_to_many :tags, :uniq => true
end
class Tag < ActiveRecord::Base
has_and_belongs_to_many :stories, :uniq => true
end
class CreateTags < ActiveRecord::Migration
def change
create_table :tags do |t|
t.string :name
t.timestamps
end
end
end
class CreateStoriesTags < ActiveRecord::Migration
def change
create_table :stories_tags, :id => false do |t|
t.references :story, :tag
end
add_index :stories_tags, [:story_id, :tag_id]
end
end
And finally, here is the relevant schema.db:
create_table "stories", :force => true do |t|
t.string "title"
t.integer "user_id"
t.datetime "created_at"
t.datetime "updated_at"
end
add_index "stories", ["user_id"], :name => "index_stories_on_user_id"
create_table "stories_tags", :id => false, :force => true do |t|
t.integer "story_id"
t.integer "tag_id"
end
add_index "stories_tags", ["story_id", "tag_id"], :name => "index_stories_tags_on_story_id_and_tag_id"
create_table "tags", :force => true do |t|
t.string "name"
t.datetime "created_at"
t.datetime "updated_at"
end
I migrated the DB and then played around with the associations in the console. Now I want to rollback the migration so to add some additional columns to the tags table. (I know that I could simply create a new migration, but I would still want to understand why I'm facing this problem.) Now, when I insert rake db:rollback into the console here is the initial output:
[nw0.0.1master (development)]$ rake db:rollback
== CreateStoriesTags: reverting ==============================================
-- drop_table(:stories_tags)
So far so good, but then the rake task just hangs . . . for hours. If I ctrl-c out of it here is the output to the console:
^Crake aborted!
An error has occurred, this and all later migrations canceled:
Interrupt: : ROLLBACK
/.rvm/gems/ruby-1.9.2-p290#rails3firstgemset/gems/activerecord-3.1.10/lib/active_record/connection_adapters/postgresql_adapter.rb:605:in `async_exec'
/.rvm/gems/ruby-1.9.2-p290#rails3firstgemset/gems/activerecord-3.1.10/lib/active_record/connection_adapters/postgresql_adapter.rb:605:in `block in execute'
/.rvm/gems/ruby-1.9.2-p290#rails3firstgemset/gems/activerecord-3.1.10/lib/active_record/connection_adapters/abstract_adapter.rb:245:in `block in log'
/.rvm/gems/ruby-1.9.2-p290#rails3firstgemset/gems/activesupport-3.1.10/lib/active_support/notifications/instrumenter.rb:21:in `instrument'
/.rvm/gems/ruby-1.9.2-p290#rails3firstgemset/gems/activerecord-3.1.10/lib/active_record/connection_adapters/abstract_adapter.rb:240:in `log'
/.rvm/gems/ruby-1.9.2-p290#rails3firstgemset/gems/activerecord-3.1.10/lib/active_record/connection_adapters/postgresql_adapter.rb:604:in `execute'
/.rvm/gems/ruby-1.9.2-p290#rails3firstgemset/gems/activerecord-3.1.10/lib/active_record/connection_adapters/postgresql_adapter.rb:664:in `rollback_db_transaction'
/.rvm/gems/ruby-1.9.2-p290#rails3firstgemset/gems/activerecord-3.1.10/lib/active_record/connection_adapters/abstract/database_statements.rb:201:in `rescue in transaction'
/.rvm/gems/ruby-1.9.2-p290#rails3firstgemset/gems/activerecord-3.1.10/lib/active_record/connection_adapters/abstract/database_statements.rb:182:in `transaction'
/.rvm/gems/ruby-1.9.2-p290#rails3firstgemset/gems/activerecord-3.1.10/lib/active_record/transactions.rb:208:in `transaction'
/.rvm/gems/ruby-1.9.2-p290#rails3firstgemset/gems/activerecord-3.1.10/lib/active_record/migration.rb:742:in `ddl_transaction'
/.rvm/gems/ruby-1.9.2-p290#rails3firstgemset/gems/activerecord-3.1.10/lib/active_record/migration.rb:686:in `block in migrate'
/.rvm/gems/ruby-1.9.2-p290#rails3firstgemset/gems/activerecord-3.1.10/lib/active_record/migration.rb:671:in `each'
/.rvm/gems/ruby-1.9.2-p290#rails3firstgemset/gems/activerecord-3.1.10/lib/active_record/migration.rb:671:in `migrate'
/.rvm/gems/ruby-1.9.2-p290#rails3firstgemset/gems/activerecord-3.1.10/lib/active_record/migration.rb:553:in `down'
/.rvm/gems/ruby-1.9.2-p290#rails3firstgemset/gems/activerecord-3.1.10/lib/active_record/migration.rb:627:in `move'
/.rvm/gems/ruby-1.9.2-p290#rails3firstgemset/gems/activerecord-3.1.10/lib/active_record/migration.rb:541:in `rollback'
/.rvm/gems/ruby-1.9.2-p290#rails3firstgemset/gems/activerecord-3.1.10/lib/active_record/railties/databases.rake:232:in `block (2 levels) in <top (required)>'
Tasks: TOP => db:rollback
(See full trace by running task with --trace)
Couple of things to note, as this app started out w/ rails 3.0, all early migrations use the older Class.up Class.down methods to define the migrations. Also, when I first expirienced the hanging I switched the CreateStoriesTags migration to use up and down instance methods, but everything still hung.
UPDATE AND THE ANSWER
I noticed that the PGAdmin3 Workbench was also hanging. So, I restarted the Mac and now the rollbacks are working just find.

Answer 1

Turned out to be a problem with my db server. A simple restart fixed the problem