Postgres adapter misconfigured on Linux?

[Benjamin Nash]

I've written a simple Rails migration that adds an index to an existing Postgres table:

class AddIndexToEvents < ActiveRecord::Migration
  def change
    add_index :sf_events, :account_id
  end
end

However, when I run the migration, it fails due to a syntax error on the CREATE INDEX line.  I'm expecting some SQL like this to be generated:

CREATE INDEX index_sf_events_on_account_id ON sf_events (account_id);

But instead I get something like this:

CREATE INDEX index_sf_events_on_account_id ON sf_events  ( );

The migration works fine on my friend's Mac, but it fails on my Linux box.  It seems like I may have the wrong/outdated packages.   I'm running Ubuntu 12.10 and have these packages installed: libpq-dev, libpq5, postgresql, postgresql-9.1, postgresql-client-9.1, postgresql-client-common, postgresql-common, postgresql-contrib, postgresql-contrib-9.1.  

Here's the full error message:

==  AddIndexToEvents: migrating ===============================================
rake aborted!
An error has occurred, this and all later migrations canceled:
PG::Error: ERROR:  syntax error at or near ")"
LINE 1: ...ATE  INDEX "index_sf_events_on_account_id" ON "sf_events"( )
                                                                      ^
: CREATE  INDEX "index_sf_events_on_account_id" ON "sf_events"( )/home/ben/.rvm/gems/ruby-1.9.3-p392-railsexpress@workbench-api/gems/activerecord-3.2.13/lib/active_record/connection_adapters/postgresql_adapter.rb:650:in `async_exec'
/home/ben/.rvm/gems/ruby-1.9.3-p392-railsexpress@workbench-api/gems/activerecord-3.2.13/lib/active_record/connection_adapters/postgresql_adapter.rb:650:in `block in execute'
/home/ben/.rvm/gems/ruby-1.9.3-p392-railsexpress@workbench-api/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract_adapter.rb:280:in `block in log'
/home/ben/.rvm/gems/ruby-1.9.3-p392-railsexpress@workbench-api/gems/activesupport-3.2.13/lib/active_support/notifications/instrumenter.rb:20:in `instrument'
/home/ben/.rvm/gems/ruby-1.9.3-p392-railsexpress@workbench-api/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract_adapter.rb:275:in `log'
/home/ben/.rvm/gems/ruby-1.9.3-p392-railsexpress@workbench-api/gems/activerecord-3.2.13/lib/active_record/connection_adapters/postgresql_adapter.rb:649:in `execute'
/home/ben/.rvm/gems/ruby-1.9.3-p392-railsexpress@workbench-api/gems/postgres_ext-0.4.0/lib/postgres_ext/active_record/connection_adapters/postgres_adapter.rb:326:in `add_index'
/home/ben/.rvm/gems/ruby-1.9.3-p392-railsexpress@workbench-api/gems/pg_power-1.5.0/lib/pg_power/create_index_concurrently.rb:82:in `add_index'
/home/ben/git/workbench-api/db/migrate/20130723195953_add_index_to_events.rb:3:in `change'
/home/ben/.rvm/gems/ruby-1.9.3-p392-railsexpress@workbench-api/gems/activerecord-3.2.13/lib/active_record/migration.rb:407:in `block (2 levels) in migrate'
/home/ben/.rvm/gems/ruby-1.9.3-p392-railsexpress@workbench-api/gems/activerecord-3.2.13/lib/active_record/migration.rb:407:in `block in migrate'
/home/ben/.rvm/gems/ruby-1.9.3-p392-railsexpress@workbench-api/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract/connection_pool.rb:129:in `with_connection'
/home/ben/.rvm/gems/ruby-1.9.3-p392-railsexpress@workbench-api/gems/activerecord-3.2.13/lib/active_record/migration.rb:389:in `migrate'
/home/ben/.rvm/gems/ruby-1.9.3-p392-railsexpress@workbench-api/gems/activerecord-3.2.13/lib/active_record/migration.rb:528:in `migrate'
/home/ben/.rvm/gems/ruby-1.9.3-p392-railsexpress@workbench-api/gems/activerecord-3.2.13/lib/active_record/migration.rb:720:in `block (2 levels) in migrate'
/home/ben/.rvm/gems/ruby-1.9.3-p392-railsexpress@workbench-api/gems/activerecord-3.2.13/lib/active_record/migration.rb:775:in `call'
/home/ben/.rvm/gems/ruby-1.9.3-p392-railsexpress@workbench-api/gems/activerecord-3.2.13/lib/active_record/migration.rb:775:in `block in ddl_transaction'
/home/ben/.rvm/gems/ruby-1.9.3-p392-railsexpress@workbench-api/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract/database_statements.rb:192:in `transaction'
/home/ben/.rvm/gems/ruby-1.9.3-p392-railsexpress@workbench-api/gems/activerecord-3.2.13/lib/active_record/transactions.rb:208:in `transaction'
/home/ben/.rvm/gems/ruby-1.9.3-p392-railsexpress@workbench-api/gems/activerecord-3.2.13/lib/active_record/migration.rb:775:in `ddl_transaction'
/home/ben/.rvm/gems/ruby-1.9.3-p392-railsexpress@workbench-api/gems/pg_power-1.5.0/lib/pg_power/create_index_concurrently.rb:201:in `ddl_transaction_with_postponed_queries'
/home/ben/.rvm/gems/ruby-1.9.3-p392-railsexpress@workbench-api/gems/activerecord-3.2.13/lib/active_record/migration.rb:719:in `block in migrate'
/home/ben/.rvm/gems/ruby-1.9.3-p392-railsexpress@workbench-api/gems/activerecord-3.2.13/lib/active_record/migration.rb:700:in `each'
/home/ben/.rvm/gems/ruby-1.9.3-p392-railsexpress@workbench-api/gems/activerecord-3.2.13/lib/active_record/migration.rb:700:in `migrate'
/home/ben/.rvm/gems/ruby-1.9.3-p392-railsexpress@workbench-api/gems/activerecord-3.2.13/lib/active_record/migration.rb:570:in `up'
/home/ben/.rvm/gems/ruby-1.9.3-p392-railsexpress@workbench-api/gems/activerecord-3.2.13/lib/active_record/migration.rb:551:in `migrate'
/home/ben/.rvm/gems/ruby-1.9.3-p392-railsexpress@workbench-api/gems/activerecord-3.2.13/lib/active_record/railties/databases.rake:193:in `block (2 levels) in <top (required)>'
/home/ben/.rvm/gems/ruby-1.9.3-p392-railsexpress@global/gems/rake-10.0.4/lib/rake/task.rb:246:in `call'
/home/ben/.rvm/gems/ruby-1.9.3-p392-railsexpress@global/gems/rake-10.0.4/lib/rake/task.rb:246:in `block in execute'
/home/ben/.rvm/gems/ruby-1.9.3-p392-railsexpress@global/gems/rake-10.0.4/lib/rake/task.rb:241:in `each'
/home/ben/.rvm/gems/ruby-1.9.3-p392-railsexpress@global/gems/rake-10.0.4/lib/rake/task.rb:241:in `execute'
/home/ben/.rvm/gems/ruby-1.9.3-p392-railsexpress@global/gems/rake-10.0.4/lib/rake/task.rb:184:in `block in invoke_with_call_chain'
/home/ben/.rvm/gems/ruby-1.9.3-p392-railsexpress@global/gems/rake-10.0.4/lib/rake/task.rb:177:in `invoke_with_call_chain'
/home/ben/.rvm/gems/ruby-1.9.3-p392-railsexpress@global/gems/rake-10.0.4/lib/rake/task.rb:170:in `invoke'
/home/ben/.rvm/gems/ruby-1.9.3-p392-railsexpress@global/gems/rake-10.0.4/lib/rake/application.rb:143:in `invoke_task'
/home/ben/.rvm/gems/ruby-1.9.3-p392-railsexpress@global/gems/rake-10.0.4/lib/rake/application.rb:101:in `block (2 levels) in top_level'
/home/ben/.rvm/gems/ruby-1.9.3-p392-railsexpress@global/gems/rake-10.0.4/lib/rake/application.rb:101:in `each'
/home/ben/.rvm/gems/ruby-1.9.3-p392-railsexpress@global/gems/rake-10.0.4/lib/rake/application.rb:101:in `block in top_level'
/home/ben/.rvm/gems/ruby-1.9.3-p392-railsexpress@global/gems/rake-10.0.4/lib/rake/application.rb:110:in `run_with_threads'
/home/ben/.rvm/gems/ruby-1.9.3-p392-railsexpress@global/gems/rake-10.0.4/lib/rake/application.rb:95:in `top_level'
/home/ben/.rvm/gems/ruby-1.9.3-p392-railsexpress@global/gems/rake-10.0.4/lib/rake/application.rb:73:in `block in run'
/home/ben/.rvm/gems/ruby-1.9.3-p392-railsexpress@global/gems/rake-10.0.4/lib/rake/application.rb:160:in `standard_exception_handling'
/home/ben/.rvm/gems/ruby-1.9.3-p392-railsexpress@global/gems/rake-10.0.4/lib/rake/application.rb:70:in `run'
/home/ben/.rvm/gems/ruby-1.9.3-p392-railsexpress@workbench-api/bin/ruby_noexec_wrapper:14:in `eval'
/home/ben/.rvm/gems/ruby-1.9.3-p392-railsexpress@workbench-api/bin/ruby_noexec_wrapper:14:in `<main>'
Tasks: TOP => db:migrate
(See full trace by running task with --trace)

[Benjamin Nash]

No Postgres adapter was broken.  It turns out that another developer had installed the postgres_ext gem, which doesn't support add_index.  Removing that gem fixed the failures.