From: Daniel DeLorme <dan-ml@...42.com>
Date: 2009-06-23T08:48:47+09:00
Subject: Re: ActiveRecord.connection_pool separate connections for each p

Virendra Negi wrote:
> Hi!
> 
> I am creating an ActiveRecord connection. In my code I am forking
> multiple processes which uses this ActiveRecord connection.
> However when the forked process ends it release the ActiveRecord
> Connection and I get the exception Mysql::Error: MySQL server has gone
> away

I also wrestled with this problem for a long time. The problem is that 
when the mysql connection is finalized, either because the process exits 
or due to garbage collection, it sends a "close" message to the server. 
The parent process, which uses the same connection, suddenly finds the 
server is no longer there. Here is the solution that I found:

   Process.fork{
     ActiveRecord::Base.active_connections.values.each(&:connect)
     #do your stuff here
   }

This code establishes a new connection for each forked child, but 
without shutting down the connection inherited from the parent.

Daniel