# Session error in rails 1.1

**URL:** <https://www.ruby-forum.com/t/session-error-in-rails-1-1/56893>\
**Category:** Rails\
**Created:** [April 5, 2006, 4:49pm UTC](https://www.ruby-forum.com/t/session-error-in-rails-1-1/56893 "2006-04-05T16:49:55Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![adamdorsey](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/ed8c4c/32.png) [@adamdorsey](https://www.ruby-forum.com/u/adamdorsey)\
**Post date:** [April 5, 2006, 4:49pm UTC](https://www.ruby-forum.com/t/session-error-in-rails-1-1/56893/1 "2006-04-05T16:49:55Z")

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I keep getting this error in rails 1.1, does anybody know what it means?  
My  
site will be working fine, i do some more development, get a parse  
error,  
and then all of a sudden the page 404’s with the following error

Session contains objects whose class definition isn’t available  
Remember to require the classes for all objects kept in the session.  
(Original exception: uninitialized constant BigDecimal [NameError])

Any ideas here ? Clearing all the sessions and cookies brings  
everything  
back to normal… not sure whats going on. This is on Rails 1.1, Linux,  
Ruby  
1.8.4, Postgres

thanks  
adam

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**Author:** ![adamdorsey](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/ed8c4c/32.png) [@adamdorsey](https://www.ruby-forum.com/u/adamdorsey)\
**Post date:** [April 5, 2006, 4:56pm UTC](https://www.ruby-forum.com/t/session-error-in-rails-1-1/56893/2 "2006-04-05T16:56:01Z")

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You have changed your model since your sessions were created. This  
causes a mismatch and and the error. Each time you change your model or  
database your sessions will no longer be valid. That’s why clearing  
them fixes the problem.

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**Author:** ![adamdorsey](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/ed8c4c/32.png) [@adamdorsey](https://www.ruby-forum.com/u/adamdorsey)\
**Post date:** [April 5, 2006, 5:08pm UTC](https://www.ruby-forum.com/t/session-error-in-rails-1-1/56893/3 "2006-04-05T17:08:18Z")

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Thanks for the explanation. However my model and database (column  
definitions) were not changed here. Anything else that would cause  
this?  
All that happened was i had a parse error in an rhtml page, fixed it, i  
reloaded and then got this and wouldnt go away.

adam

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**Author:** ![adamdorsey](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/ed8c4c/32.png) [@adamdorsey](https://www.ruby-forum.com/u/adamdorsey)\
**Post date:** [April 5, 2006, 5:17pm UTC](https://www.ruby-forum.com/t/session-error-in-rails-1-1/56893/4 "2006-04-05T17:17:27Z")

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I’m not sure. I know that rails will die if you try to access an object  
in your session that rails knows nothing about. What are you storing in  
your session?

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**Author:** ![adamdorsey](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/ed8c4c/32.png) [@adamdorsey](https://www.ruby-forum.com/u/adamdorsey)\
**Post date:** [April 5, 2006, 5:25pm UTC](https://www.ruby-forum.com/t/session-error-in-rails-1-1/56893/5 "2006-04-05T17:25:57Z")

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Adam D. wrote:

> Thanks for the explanation. However my model and database (column  
> definitions) were not changed here. Anything else that would cause  
> this?  
> All that happened was i had a parse error in an rhtml page, fixed it, i  
> reloaded and then got this and wouldnt go away.
> 
> adam

This looks relevant:

[http://wiki.rubyonrails.org/rails/pages/HowtoAvoidSessionRestoreError](http://wiki.rubyonrails.org/rails/pages/HowtoAvoidSessionRestoreError)

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<div class="post-metadata">

**Author:** ![adamdorsey](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/ed8c4c/32.png) [@adamdorsey](https://www.ruby-forum.com/u/adamdorsey)\
**Post date:** [April 5, 2006, 6:28pm UTC](https://www.ruby-forum.com/t/session-error-in-rails-1-1/56893/6 "2006-04-05T18:28:03Z")

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hmm nice post, that does appear to be very relevant.