# Mongrels Hanging in mysql\_adapter.rb

**URL:** <https://www.ruby-forum.com/t/mongrels-hanging-in-mysql-adapter-rb/182336>\
**Category:** Rails\
**Created:** [January 26, 2010, 6:43pm UTC](https://www.ruby-forum.com/t/mongrels-hanging-in-mysql-adapter-rb/182336 "2010-01-26T18:43:20Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![serty](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/b5e925/32.png) [@serty](https://www.ruby-forum.com/u/serty)\
**Post date:** [January 26, 2010, 6:43pm UTC](https://www.ruby-forum.com/t/mongrels-hanging-in-mysql-adapter-rb/182336/1 "2010-01-26T18:43:20Z")

</div>

Hi everyone,

I have been trying to solve this problem for quite some time now and I  
really don’t have any further clue to investigate.

I am running a mongrel\_cluster 1.0.5-2 (mongrel verison : 1.1.5-5) on  
a ubuntu box with apache2 2.2.12-1ubuntu2.1

I have 4 different apps on the same box and each app has two mongrel  
instances.

After a short period of time ( \< 2 hours ) some of the 8 mongrel  
instances just stop responding.

I read the mongrel FAQ and tried to set  
ActiveRecord::Base.verification\_timeout = 14400 (the mysql parameter  
is set to the default 28800) in myapp/config/environments/  
production.rb

The problem kept happening.

I decided to lower that number, making it 60.  
No more success.

I installed gdb and the ruby macros to make sure i was in the mysql  
driver while hanging and sure enough, here is the top of the BT from  
GDB :

/var/lib/gems/1.8/gems/activerecord-2.2.2/lib/active\_record/  
connection\_adapters/mysql\_adapter.rb:264:in `active?'", "/var/lib/gems/1.8/gems/activerecord-2.2.2/lib/active_record/ connection_adapters/abstract_adapter.rb:136:in`verify!’",  
“/var/lib/gems/1.8/gems/activerecord-2.2.2/lib/active\_record/  
connection\_adapters/abstract/connection\_pool.rb:256:in  
`checkout_and_verify'", "/var/lib/gems/1.8/gems/activerecord-2.2.2/lib/active_record/ connection_adapters/abstract/connection_pool.rb:252:in`checkout\_existing\_connection’”,  
“/var/lib/gems/1.8/gems/activerecord-2.2.2/lib/active\_record/  
connection\_adapters/abstract/connection\_pool.rb:186:in `checkout'", "/var/lib/gems/1.8/gems/activerecord-2.2.2/lib/active_record/ connection_adapters/abstract/connection_pool.rb:184:in`loop’”,  
“/var/lib/gems/1.8/gems/activerecord-2.2.2/lib/active\_record/  
connection\_adapters/abstract/connection\_pool.rb:184:in `checkout'", "/usr/lib/ruby/1.8/monitor.rb:242:in`synchronize’”,  
“/var/lib/gems/1.8/gems/activerecord-2.2.2/lib/active\_record/  
connection\_adapters/abstract/connection\_pool.rb:183:in `checkout'", "/var/lib/gems/1.8/gems/activerecord-2.2.2/lib/active_record/ connection_adapters/abstract/connection_pool.rb:98:in`connection’”,  
“/var/lib/gems/1.8/gems/activerecord-2.2.2/lib/active\_record/  
connection\_adapters/abstract/connection\_pool.rb:326:in  
`retrieve_connection'", "/var/lib/gems/1.8/gems/activerecord-2.2.2/lib/active_record/ connection_adapters/abstract/connection_specification.rb:121:in`retrieve\_connection’”,  
“/var/lib/gems/1.8/gems/activerecord-2.2.2/lib/active\_record/  
connection\_adapters/abstract/connection\_specification.rb:113:in  
`connection'", "/var/lib/gems/1.8/gems/activerecord-2.2.2/lib/active_record/base.rb: 2934:in`quoted\_table\_name’”,  
“/var/lib/gems/1.8/gems/activerecord-2.2.2/lib/active\_record/base.rb:  
1626:in `construct_finder_sql'", "/var/lib/gems/1.8/gems/activerecord-2.2.2/lib/active_record/base.rb: 1490:in`find\_every’”,  
“/var/lib/gems/1.8/gems/activerecord-2.2.2/lib/active\_record/base.rb:  
589:in `find’”,

I figured that since I was running a packaged version of  
mongrel\_cluster (not the gem installed one), I should use the package  
version of mysql driver for ruby.  
So i did  
gem uninstall mysql

and installed :  
apt-get install libmysql-ruby1.8

I then restarted the mongrels and sure enough after 1h25 one of them  
was hanging in the mysql\_adapter.rb, showing the same backtrace as  
before.

I really am out of clue here and any advice / help would be much  
appreciated.

I have to note that I am far from being an ROR guru and maybe the  
solution to my problem is simpler than what I have been looking for,  
but I just don’t know where to look anymore.

Thanks for any advice / answer

Damien

---

<div class="post-metadata">

**Author:** ![serty](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/b5e925/32.png) [@serty](https://www.ruby-forum.com/u/serty)\
**Post date:** [January 27, 2010, 2:11pm UTC](https://www.ruby-forum.com/t/mongrels-hanging-in-mysql-adapter-rb/182336/2 "2010-01-27T14:11:54Z")

</div>

For the record, our problem was sitting with the firewall between the  
app  
box and the mysql box.  
There seems to be a 4000 seconds timeout on any TCP connection passing  
through the firewall…  
I followed the steps detailed here :  
[https://boxpanel.blueboxgrp.com/public/the\_vault/index.php/Mongrel\_/\_MySQL\_Timeout](https://boxpanel.blueboxgrp.com/public/the_vault/index.php/Mongrel_/_MySQL_Timeout)  
[https://boxpanel.blueboxgrp.com/public/the\_vault/index.php/Mongrel\_/\_MySQL\_Timeout](https://boxpanel.blueboxgrp.com/public/the_vault/index.php/Mongrel_/_MySQL_Timeout)Making  
it 900.times and the timeout = 1800

It seems to have done the trick.  
I don’t like this solution, but hell, it’s the better of two evils I  
think.

It’ll do for now but if anyone has another way of seing things, be sure  
to  
let me know 😉

Damien

2010/1/26 serty [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)