#101 new
hbeaver (at gmail)

ActiveRecord connection does not reconnect when using Thin/Sinatra but works fine with just Sinatra.

Reported by hbeaver (at gmail) | May 28th, 2009 @ 03:37 PM | in Future

I have a very simple model for a simple web service. Any call to model will throw 500, like Model.find(:first) after 10 seconds.


application error
ActiveRecord::StatementInvalid at /leads
Mysql::Error: MySQL server has gone away: SELECT * FROM leads

Setting this in model does not help:

  before do 



I have set MySQL to 10 seconds timeout to duplicate the issue quickly using this:

SET GLOBAL wait_timeout=10;
SET GLOBAL interactive_timeout=10; 
SET SESSION wait_timeout=10;
SET SESSION interactive_timeout=10;

show GLOBAL VARIABLES like 'wait_timeout'; 
show GLOBAL VARIABLES like 'interactive_timeout';
show SESSION VARIABLES like 'wait_timeout';
show SESSION VARIABLES like 'wait_timeout';

If I use rackup on the Sinatra app, no problem. When I use thin I receive the error. Here is my thin config:

pid: tmp/pids/thin.pid
log: log/thin.log
timeout: 30
port: 4600
max_conns: 1024
chdir: /Users/hbeaver/code/primedia/service_leads/
rackup: /Users/hbeaver/code/primedia/service_leads/config.ru
max_persistent_conns: 512
environment: development
daemonize: true
require: []

servers: 1


Comments and changes to this ticket

  • hbeaver (at gmail)

    hbeaver (at gmail) May 29th, 2009 @ 06:18 PM


    I moved the "before do" into extended Sinatra::Default class as opposed to model and issue was resolved. However, this does not explain why mongrel will create a new connection auto-magically whereas thin will not. Please see 2 attached tcpdumps named appropriately, 'thin_no_reconnect_example.dump' and 'mongrel_reconnect_example.dump'.

    In both, the server has just been started and then a HTTP request is made to a one line action that does Model.find(:first). In both, a mysql connection is created ok after server is started. After approx. 10 seconds (because of the wait_timeout setting in the ticket I mentioned yesterday) mysql will sent a FIN/ACK (disconnect). Shortly thereafter another HTTP request is made to server. Mongrel creates yet another connection, but thin will not. I am not certain if this is a bug or just the nature of thin.

    I thought it important to present this information.

    Thanks again,

  • hbeaver (at gmail)

    hbeaver (at gmail) August 10th, 2009 @ 01:05 PM

    • Assigned user cleared.

    As mentioned above, I resolved this issue by moving ActiveRecord::Base.connection.verify! into Sinatra class before do block:

    class NewApp < Sinatra::Default   
      before do
    end #end of Sinatra class
  • Conny Brunnkvist

    Conny Brunnkvist July 21st, 2010 @ 07:15 PM

    • Milestone order changed from “0” to “0”

    Same problem here.

    Works when running in foreground but as soon as either of "-s 1" or "servers: 1" is set, ActiveRecord is can't connect.

  • Conny Brunnkvist

    Conny Brunnkvist July 26th, 2010 @ 12:22 PM

    I wonder if we don't need to simply ActiveRecord::Base.establish_connection after forking.. but then, why wouldn't reconnect! work? I gave up on this one, will try again later perhaps.

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