Moving a Rails app from MySQL 5 to Postgres 9

At Bloomfire we recently decided to do a full migration over from MySQL 5 to Postgresql 9. There are a number of reasons for this, including scalability, better feature sets (such as Psql’s full text search engine) and getting away from Oracle before we are forced to move. For the sake of this post, detailed reasons aren’t important.

What I’ve put together here are the few issues we ran into and changes we had to make to get the application working under Postgres. Overall the code changes are minimal as we mostly use ActiveRecord code for communication, and in the places we write SQL directly it was mostly standards compliant. That said here’s what we did have to change.

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