Ruby, Rails: mysql2 gem, does somebody use this gem? Is it stable?

Question

I found mysql2 gem. It works fine with ruby 1.9 and utf8 encoding (as opposed to mysql gem).

But I have doubts. Does somebody use this gem in production? What about the performance test? Is it faster than mysql gem? Is it stable?

Answer 1

mysql2 is meant as a more modern replacement for the existing mysql gem, which has been stale for a while now. I also heard that the author isn't supporting it anymore and instead recommends everyone use his pure-ruby version since it's compatible with more Ruby implementations (but is much slower).

The first issue with the mysql gem is it doesn't do any type casting in C, it gives you back ruby strings which you then have to convert into proper ruby types. Doing that in pure-ruby is extremely slow, and creates objects on the heap that never needed to existing in the first place. And as we all know, Ruby's GC is it's primary reason for it's slowness. So it's best to avoid it and do as much in pure C as you can.

Second is that it blocks the entire ruby VM while connecting, sending queries and waiting for responses, and even closing the connection. mysqlplus definitely helps with this issue, but only for sending queries as far as I know.

mysql2 aims to solve these problems while keeping the API extremely simple. Eric Wong (author of Unicorn) has contributed some awesome patches that make nearly everything non-blocking and/or release the GVL in Ruby. The Mysql2::Result class implements Enumerable so if you know how to use an Array, you know how to use it.

I'm only aware of a few people using it in production right now but it is being evaluated at Twitter, WorkingPoint and UserVoice too.

I'm also in talks with Yehuda about it being the recommended/default for Rails 3 when it ships. Some of its techniques and optimizations are also going to be brought into DataObjects' do_mysql driver soon as well.

The ActiveRecord driver should be pretty solid at the moment. All you should need to do is have the gem installed, and change your adapter name in database.yml to mysql2.

If you're interested in using it, give it a try. I'm quick to push fixes if you find any issues ;)

Answer 2

mysql2 is now the default in rails 3

Answer 3

A bit late - but I'm using mysql2 in production on a couple of sites, and have found it very stable since some issues with connections getting closed were resolved a few weeks ago.