Rails - Jul 2006 - ActiveRecord thread-safety

Hi,

I want to use ActiveRecord outside Rails. The application is 
multithreaded, so database access has to be thread-safe. I read in a few 
places ActiveRecord in fact should be thread-safe and I gave it a try, 
but my findings indicate ActiveRecord is NOT thread-safe.
The following test-script fails every with a lost MySQL-connenction:

require ''rubygems''
require_gem ''activerecord''
require ''models/user.rb''

ActiveRecord::Base.establish_connection(
  :adapter => ''mysql'', :host =>
''localhost'',
  :database => ''test'', :username =>
''test''
)

if (!User.find(:first))
  User.create(:name => ''dummy'', :password =>
''unsecure'')
end

threads = []

20.times do |i|
  t = Thread.new do
    User.find(:first)
  end
  threads.push(t)
end
threads.each { |t| t.join }


(to reproduce, replace the database and model with something present on 
your system).
the error message:
Mysql::Error: Lost connection to MySQL server during query: ...


if anybody could shed some light on how thread-safe ActiveRecord really 
is it would be very much appreciated.

Thx,
Michael

-- 
Posted via http://www.ruby-forum.com/.

On 7/7/06, Michael B?rge <mib@vis.ethz.ch> wrote:
> I want to use ActiveRecord outside Rails. The application is
> multithreaded, so database access has to be thread-safe. I read in a few
> places ActiveRecord in fact should be thread-safe and I gave it a try,
> but my findings indicate ActiveRecord is NOT thread-safe.
Have you checked the value of ActiveRecord::Base.allow_concurrency is
set to true?

Tom

Wow, never have seen that before!

It''s not even in the apidocs (http://api.rubyonrails.org/) but
exists...

It there a more accurate documentation sneaking around somewhere?! :-)

regards
Peter


Tom Ward schrieb:
> On 7/7/06, Michael B?rge <mib@vis.ethz.ch> wrote:
>
>> I want to use ActiveRecord outside Rails. The application is
>> multithreaded, so database access has to be thread-safe. I read in a
few
>> places ActiveRecord in fact should be thread-safe and I gave it a try,
>> but my findings indicate ActiveRecord is NOT thread-safe.
>
> Have you checked the value of ActiveRecord::Base.allow_concurrency is
> set to true?
>
> Tom
> ------------------------------------------------------------------------
>
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>

> Have you checked the value of ActiveRecord::Base.allow_concurrency is
> set to true?
No I didn''t! ...didn''t know it existed.
It was set to false and when set to true my test works as desired.

That was the missing piece of information needed, thank you very much!

I guess I will look at the sources more from now on after unsuccessful 
searches for documentation/explanation ;-)

Michael

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Posted via http://www.ruby-forum.com/.