# Wrong argument type Mysql (expected Struct) running rake with Ruby 1.9 / Rails 2.3.3

**URL:** <https://www.ruby-forum.com/t/wrong-argument-type-mysql-expected-struct-running-rake-with-ruby-1-9-rails-2-3-3/178610>\
**Category:** Rails\
**Created:** [November 7, 2009, 8:34pm UTC](https://www.ruby-forum.com/t/wrong-argument-type-mysql-expected-struct-running-rake-with-ruby-1-9-rails-2-3-3/178610 "2009-11-07T20:34:46Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![paulbutcher](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/a5b964/32.png) [@paulbutcher](https://www.ruby-forum.com/u/paulbutcher)\
**Post date:** [November 7, 2009, 8:34pm UTC](https://www.ruby-forum.com/t/wrong-argument-type-mysql-expected-struct-running-rake-with-ruby-1-9-rails-2-3-3/178610/1 "2009-11-07T20:34:46Z")

</div>

I’m use Ruby 1.9 via rvm and Rails 2.3.3. I’m on OS X 10.5 and I have  
the mysql 2.8.1 gem installed. When I run rake on my rails app, I get  
the error “wrong argument type Mysql (expected Struct)”. I can run  
the app fine with script/server and script/console fine. Is anyone  
else having this problem or know what might cause this problem?  
Here’s the stack trace:

~/Development/Projects/paulbarry(master)[ruby:1.9.1:p243] $ rake –  
trace  
(in /Users/pbarry/Development/Projects/paulbarry)  
\*\* Invoke default (first\_time)  
\*\* Invoke spec (first\_time)  
\*\* Invoke db:test:prepare (first\_time)  
\*\* Invoke db:abort\_if\_pending\_migrations (first\_time)  
\*\* Invoke environment (first\_time)  
\*\* Execute environment  
\*\* Execute db:abort\_if\_pending\_migrations  
rake aborted!  
wrong argument type Mysql (expected Struct)  
/Users/pbarry/.rvm/gems/ruby/1.9.1/gems/activerecord-2.3.3/lib/  
active\_record/connection\_adapters/mysql\_adapter.rb:576:in  
`real_connect' /Users/pbarry/.rvm/gems/ruby/1.9.1/gems/activerecord-2.3.3/lib/ active_record/connection_adapters/mysql_adapter.rb:576:in`connect’  
/Users/pbarry/.rvm/gems/ruby/1.9.1/gems/activerecord-2.3.3/lib/  
active\_record/connection\_adapters/mysql\_adapter.rb:204:in `initialize' /Users/pbarry/.rvm/gems/ruby/1.9.1/gems/activerecord-2.3.3/lib/ active_record/connection_adapters/mysql_adapter.rb:76:in`new’  
/Users/pbarry/.rvm/gems/ruby/1.9.1/gems/activerecord-2.3.3/lib/  
active\_record/connection\_adapters/mysql\_adapter.rb:76:in  
`mysql_connection' /Users/pbarry/.rvm/gems/ruby/1.9.1/gems/activerecord-2.3.3/lib/ active_record/connection_adapters/abstract/connection_pool.rb:223:in`send’  
/Users/pbarry/.rvm/gems/ruby/1.9.1/gems/activerecord-2.3.3/lib/  
active\_record/connection\_adapters/abstract/connection\_pool.rb:223:in  
`new_connection' /Users/pbarry/.rvm/gems/ruby/1.9.1/gems/activerecord-2.3.3/lib/ active_record/connection_adapters/abstract/connection_pool.rb:245:in`checkout\_new\_connection’  
/Users/pbarry/.rvm/gems/ruby/1.9.1/gems/activerecord-2.3.3/lib/  
active\_record/connection\_adapters/abstract/connection\_pool.rb:188:in  
`checkout' /Users/pbarry/.rvm/gems/ruby/1.9.1/gems/activerecord-2.3.3/lib/ active_record/connection_adapters/abstract/connection_pool.rb:184:in`loop’  
/Users/pbarry/.rvm/gems/ruby/1.9.1/gems/activerecord-2.3.3/lib/  
active\_record/connection\_adapters/abstract/connection\_pool.rb:184:in  
`checkout' /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/ 1.8/monitor.rb:242:in`synchronize’  
/Users/pbarry/.rvm/gems/ruby/1.9.1/gems/activerecord-2.3.3/lib/  
active\_record/connection\_adapters/abstract/connection\_pool.rb:183:in  
`checkout' /Users/pbarry/.rvm/gems/ruby/1.9.1/gems/activerecord-2.3.3/lib/ active_record/connection_adapters/abstract/connection_pool.rb:98:in`connection’  
/Users/pbarry/.rvm/gems/ruby/1.9.1/gems/activerecord-2.3.3/lib/  
active\_record/connection\_adapters/abstract/connection\_pool.rb:326:in  
`retrieve_connection' /Users/pbarry/.rvm/gems/ruby/1.9.1/gems/activerecord-2.3.3/lib/ active_record/connection_adapters/abstract/connection_specification.rb: 123:in`retrieve\_connection’  
/Users/pbarry/.rvm/gems/ruby/1.9.1/gems/activerecord-2.3.3/lib/  
active\_record/connection\_adapters/abstract/connection\_specification.rb:  
115:in `connection' /Users/pbarry/.rvm/gems/ruby/1.9.1/gems/activerecord-2.3.3/lib/ active_record/migration.rb:435:in`initialize’  
/Users/pbarry/.rvm/gems/ruby/1.9.1/gems/rails-2.3.3/lib/tasks/  
databases.rake:197:in `new' /Users/pbarry/.rvm/gems/ruby/1.9.1/gems/rails-2.3.3/lib/tasks/ databases.rake:197 /Users/pbarry/.rvm/gems/ruby/1.9.1/gems/rake-0.8.7/lib/rake.rb:636:in`call’  
/Users/pbarry/.rvm/gems/ruby/1.9.1/gems/rake-0.8.7/lib/rake.rb:636:in  
`execute' /Users/pbarry/.rvm/gems/ruby/1.9.1/gems/rake-0.8.7/lib/rake.rb:631:in`each’  
/Users/pbarry/.rvm/gems/ruby/1.9.1/gems/rake-0.8.7/lib/rake.rb:631:in  
`execute' /Users/pbarry/.rvm/gems/ruby/1.9.1/gems/rake-0.8.7/lib/rake.rb:597:in`invoke\_with\_call\_chain’  
/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/  
1.8/monitor.rb:242:in `synchronize' /Users/pbarry/.rvm/gems/ruby/1.9.1/gems/rake-0.8.7/lib/rake.rb:590:in`invoke\_with\_call\_chain’  
/Users/pbarry/.rvm/gems/ruby/1.9.1/gems/rake-0.8.7/lib/rake.rb:607:in  
`invoke_prerequisites' /Users/pbarry/.rvm/gems/ruby/1.9.1/gems/rake-0.8.7/lib/rake.rb:604:in`each’  
/Users/pbarry/.rvm/gems/ruby/1.9.1/gems/rake-0.8.7/lib/rake.rb:604:in  
`invoke_prerequisites' /Users/pbarry/.rvm/gems/ruby/1.9.1/gems/rake-0.8.7/lib/rake.rb:596:in`invoke\_with\_call\_chain’  
/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/  
1.8/monitor.rb:242:in `synchronize' /Users/pbarry/.rvm/gems/ruby/1.9.1/gems/rake-0.8.7/lib/rake.rb:590:in`invoke\_with\_call\_chain’  
/Users/pbarry/.rvm/gems/ruby/1.9.1/gems/rake-0.8.7/lib/rake.rb:607:in  
`invoke_prerequisites' /Users/pbarry/.rvm/gems/ruby/1.9.1/gems/rake-0.8.7/lib/rake.rb:604:in`each’  
/Users/pbarry/.rvm/gems/ruby/1.9.1/gems/rake-0.8.7/lib/rake.rb:604:in  
`invoke_prerequisites' /Users/pbarry/.rvm/gems/ruby/1.9.1/gems/rake-0.8.7/lib/rake.rb:596:in`invoke\_with\_call\_chain’  
/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/  
1.8/monitor.rb:242:in `synchronize' /Users/pbarry/.rvm/gems/ruby/1.9.1/gems/rake-0.8.7/lib/rake.rb:590:in`invoke\_with\_call\_chain’  
/Users/pbarry/.rvm/gems/ruby/1.9.1/gems/rake-0.8.7/lib/rake.rb:607:in  
`invoke_prerequisites' /Users/pbarry/.rvm/gems/ruby/1.9.1/gems/rake-0.8.7/lib/rake.rb:604:in`each’  
/Users/pbarry/.rvm/gems/ruby/1.9.1/gems/rake-0.8.7/lib/rake.rb:604:in  
`invoke_prerequisites' /Users/pbarry/.rvm/gems/ruby/1.9.1/gems/rake-0.8.7/lib/rake.rb:596:in`invoke\_with\_call\_chain’  
/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/  
1.8/monitor.rb:242:in `synchronize' /Users/pbarry/.rvm/gems/ruby/1.9.1/gems/rake-0.8.7/lib/rake.rb:590:in`invoke\_with\_call\_chain’  
/Users/pbarry/.rvm/gems/ruby/1.9.1/gems/rake-0.8.7/lib/rake.rb:583:in  
`invoke' /Users/pbarry/.rvm/gems/ruby/1.9.1/gems/rake-0.8.7/lib/rake.rb:2051:in`invoke\_task’  
/Users/pbarry/.rvm/gems/ruby/1.9.1/gems/rake-0.8.7/lib/rake.rb:2029:in  
`top_level' /Users/pbarry/.rvm/gems/ruby/1.9.1/gems/rake-0.8.7/lib/rake.rb:2029:in`each’  
/Users/pbarry/.rvm/gems/ruby/1.9.1/gems/rake-0.8.7/lib/rake.rb:2029:in  
`top_level' /Users/pbarry/.rvm/gems/ruby/1.9.1/gems/rake-0.8.7/lib/rake.rb:2068:in`standard\_exception\_handling’  
/Users/pbarry/.rvm/gems/ruby/1.9.1/gems/rake-0.8.7/lib/rake.rb:2023:in  
`top_level' /Users/pbarry/.rvm/gems/ruby/1.9.1/gems/rake-0.8.7/lib/rake.rb:2001:in`run’  
/Users/pbarry/.rvm/gems/ruby/1.9.1/gems/rake-0.8.7/lib/rake.rb:2068:in  
`standard_exception_handling' /Users/pbarry/.rvm/gems/ruby/1.9.1/gems/rake-0.8.7/lib/rake.rb:1998:in`run’  
/Users/pbarry/.rvm/gems/ruby/1.9.1/gems/rake-0.8.7/bin/rake:31  
/Users/pbarry/.rvm/ruby-1.9.1-p243/bin/rake:21:in `load’  
/Users/pbarry/.rvm/ruby-1.9.1-p243/bin/rake:21