Confused classes

Eric Wong normalperson at yhbt.net
Sat Feb 6 21:01:19 EST 2010


Iñaki Baz Castillo <ibc at aliax.net> wrote:
> El Sábado, 6 de Febrero de 2010, Warren Konkel escribió:
> > Could it be that class attributes are somehow being co-mingled when
> > unicorn is starting up under high concurrency?  Perhaps a mutex is
> > missing somewhere?
> 
> IMHO all your Unicorn workers are sharing the same DB connection (the same 
> ActiveRecord instances) so the problem arises.
> 
> Take a look to the configuration here:
>   http://unicorn.bogomips.org/examples/unicorn.conf.rb
> You can see there how the ActiveRecord is disconnected at the beggining and 
> started for each worker later.

Yes, you have to reconnect any connected TCP sockets since they have no
defined atomicity semantics when they're shared across processes/threads.

Ruby Mutexes aren't useful at all here, they're only useful with threads
in the same process.  If you need to protect TCP client sockets from
multiple processes, you'll need SysV/POSIX semaphores or file locks
(flock/fcntl), but you're really better off using multiple TCP client
sockets in the first place.

-- 
Eric Wong


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