Ferret talk - Oct 2006 - corrupted index preventing save

Hi, I''m using Rails/AAF with Ferret 0.10.11, and my index occasionally 
(every few weeks, roughly) becomes corrupted.

If the index is busted, until I rebuild it our users are unable to save 
anything. I get errors like the one below, and the save rolls back.

My question is, is there any way to catch the error, and continue with 
the save even if the model isn''t indexed? What would be ideal is if i 
could have a catch the error, and have it send me a notification, which 
would solve two problems: the save would still happen so our users 
wouldn''t be impacted, and I would know exactly when the index had
become
corrupted, and could rebuild it.

TIA for any help,
John


here''s the error i''m getting:


Processing UserController#signup (for 72.227.101.170 at 2006-10-31 
11:23:06) [POST]
  Session ID: 7f854fa9eaf95becbb9723a9bd48f9c2
  Parameters:
{"user"=>{"subscribe_to_newsletter"=>"0",
"password_confirmation"=>"[FILTERED]",
"terms"=>"1",
"password"=>"[FILTERED]",
"login"=>"jmcgrath",
"email"=>"jmcgrath at whoi.edu"},
"commit"=>"Sign Up",
"action"=>"signup",
"controller"=>"user"}
Unable to send confirmation E-Mail:
Lock Error occured at <except.c>:103 in xpop_context
Error occured in index.c:5371 - iw_open
        Couldn''t obtain write lock when opening IndexWriter

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On 31.10.2006, at 18:02, John Mcgrath wrote:
> Hi, I''m using Rails/AAF with Ferret 0.10.11, and my index
occasionally
> (every few weeks, roughly) becomes corrupted.
>
> If the index is busted, until I rebuild it our users are unable to  
> save
> anything. I get errors like the one below, and the save rolls back.
The acts_as_ferret plugin employs ActiveRecord callbacks such as  
after_update to index the models. If an exception is thrown inside a  
callback method, the action is rolled back.
> My question is, is there any way to catch the error, and continue with
> the save even if the model isn''t indexed?
Several ways. You could overwrite the save mehtod (either on a per- 
model-basis or for ActiveRecord::Base) to read:

def save
   begin
    create_or_update
   rescue => any_exception
    # deal with exceptions you can handle or re-raise
   end
end

Or, even better, you could patch the acts_as_ferret code to resort to  
a callback such as "rescue_error_in_ferret". See the
''ferret_create''
method of ''acts_as_ferret/lib/instance_methods.rb''.
You''d basically
wrap the method in a begin/rescue block and see if the model  
respond_to? :rescue_error_in_ferret. If it does, call that method or  
else re-raise the exception.

Cheers,
Andy

On Tue, Oct 31, 2006 at 07:47:30PM +0100, Andreas Korth
wrote:
> 
> On 31.10.2006, at 18:02, John Mcgrath wrote:
> 
> > Hi, I''m using Rails/AAF with Ferret 0.10.11, and my index
occasionally
> > (every few weeks, roughly) becomes corrupted.
> >
> > If the index is busted, until I rebuild it our users are unable to  
> > save
> > anything. I get errors like the one below, and the save rolls back.
> 
> The acts_as_ferret plugin employs ActiveRecord callbacks such as  
> after_update to index the models. If an exception is thrown inside a  
> callback method, the action is rolled back.
> 
> > My question is, is there any way to catch the error, and continue with
> > the save even if the model isn''t indexed?
> 
> Several ways. You could overwrite the save mehtod (either on a per- 
> model-basis or for ActiveRecord::Base) to read:
> 
> def save
>    begin
>     create_or_update
>    rescue => any_exception
>     # deal with exceptions you can handle or re-raise
>    end
> end
> 
> Or, even better, you could patch the acts_as_ferret code to resort to  
> a callback such as "rescue_error_in_ferret". See the
''ferret_create''
> method of ''acts_as_ferret/lib/instance_methods.rb''.
You''d basically
> wrap the method in a begin/rescue block and see if the model  
> respond_to? :rescue_error_in_ferret. If it does, call that method or  
> else re-raise the exception.
overwriting the callback handlers in your model would be another 
possibility:

class MyModel < AR::Base

  acts_as_ferret ...

  # ferret_create is declared by aaf, and used for before_update and
  # before_create events.
  alias :old_ferret_create :ferret_create
  def ferret_create
    old_ferret_create
  rescue
    # handle the error...
    true # tell AR everything is fine
  end

end


Jens

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