Mongrel users - May 2007 - Troubleshooting unresponsive mongrel

Hi. I have mongrel 1.0.1 running a really simple application and found 
to lock up (rarely, but still). There''s nothing in the logs, it just 
stops responding. When I mongrel_rails stop it, I get lots of entries like:

Waiting for 3 requests to finish, could take 60 seconds
/usr/lib64/ruby/gems/1.8/gems/mongrel-1.0.1/lib/mongrel.rb:675:in
`process''
/usr/lib64/ruby/gems/1.8/gems/mongrel-1.0.1/lib/mongrel.rb:618:in 
`process_client''
/usr/lib64/ruby/gems/1.8/gems/mongrel-1.0.1/lib/mongrel.rb:617:in 
`process_client''
/usr/lib64/ruby/gems/1.8/gems/mongrel-1.0.1/lib/mongrel.rb:736:in `run''
/usr/lib64/ruby/gems/1.8/gems/mongrel-1.0.1/lib/mongrel.rb:736:in `run''
/usr/lib64/ruby/gems/1.8/gems/mongrel-1.0.1/lib/mongrel.rb:720:in `run''
/usr/lib64/ruby/gems/1.8/gems/mongrel-1.0.1/lib/mongrel/configurator.rb:271:in 
`run''
/usr/lib64/ruby/gems/1.8/gems/mongrel-1.0.1/lib/mongrel/configurator.rb:270:in 
`run''
/usr/lib64/ruby/gems/1.8/gems/mongrel-1.0.1/bin/mongrel_rails:127:in
`run''
/usr/lib64/ruby/gems/1.8/gems/mongrel-1.0.1/lib/mongrel/command.rb:211:in 
`run''
/usr/lib64/ruby/gems/1.8/gems/mongrel-1.0.1/bin/mongrel_rails:243
/usr/bin/mongrel_rails:18Wed May 23 08:58:18 CEST 2007: Error calling 
Dispatcher.dispatch #<Mongrel::TimeoutError: Mongrel timed out this 
thread: shutdown>Thread #<Thread:0x2a9859a570 sleep> is too old,
killing.

Any tips on how to determine the cause of this? I''m running CentOS 4, 
Ruby 1.8.4.

Br,

Morten

On 5/23/07, Morten <lists at kikobu.com> wrote:
> Hi. I have mongrel 1.0.1 running a really simple application and found
> to lock up (rarely, but still).
Does it lock up after a period of inactivity? Are you using MySQL pure
Ruby driver there? If the answer is yes and yes, it''s a known MySQL
driver bug. Quoting from Mongrel FAQ:

Q: Mongrel stops working if it''s left alone for a long time.

If you find that Mongrel stops working after a long idle time and
you''re using MySQL then you''re hitting a bug in the MySQL
driver that
doesn''t properly timeout connections. What happens is the MySQL server
side of the connection times out and closes, but the MySQL client
doesn''t detect this and just sits there.

What you have to do is set:

ActiveRecord::Base.verification_timeout = 14400

Or to any value that is lower than the MySQL server''s
interactive_timeout setting. This will make sure that ActiveRecord
checks the connection often enough to reset the connection.

--
Alex Verkhovsky