Surgical slave reads for Ruby on Rails, mulitple databases

Greetings,

I'm currently working on a multiple database rails application.

I want to off load the SELECT queries on to the slave databases for only SOME of the databases or specific models.

The issue is that in places, we swap out the current database connection and put in a different one for a short time; to load fixtures or to handle sharding.

Does anyone have any recommendations on a ruby gem that

1. will split select/(sql writes) with a considerable amount of control.
   We want to handle just some models and we are looking for a 开发者_StackOverflow社区neat surgical fix.
2. does not monkey around with activerecord.
3. is still being maintained.

TIA

-daniel