how to find the cause of ActiveRecord ROLLBACK

Question

In the logs I\'m seeing a ROLLBACK, but no exception is logged. Is there a way to find out what caused the ROLLBACK?

Here\'s the excerpt of the log:

Answer 1

The 3 methodologies (1 failed) I have come up with are to

1) use an observer on active record on all the relevant save, validate methods

2) to open up active record and put a debugger statement where ROLLBACKs are triggered and then run caller to pinpoint the code that triggered the error.

3) Failed :override the active record methods and pause on exception. If I remember this method does not catch any exception because the save methods are wrapped in a transaction.

Notes: Only enable when the mode is not Rails.env.production?. Tested on Rails 3.2.13, using ruby 1.9.3.

1) Observer: http://guides.rubyonrails.org/v3.2.13/active_record_validations_callbacks.html#observers

class ActiveRecordObserver < ActiveRecord::Observer

    observe "ActiveRecord::Base"

    def after_validation(model)
        debugger if model.errors.messages.any?
        Rails.logger.error "after validation"
    end
    def before_update(model)
        debugger if !model.valid?
        Rails.logger.error "before update"
    end
    def after_update(model)
        debugger if !model.valid?
        Rails.logger.error "after update"
    end
    def before_save(model)

        debugger if model.errors.messages.any?
        Rails.logger.error "#{model}" Rails.logger.error "before save"
    end
    def after_save(model)
        debugger if model.errors.messages.any?
        Rails.logger.error "after save"
    end
end

2) https://github.com/rails/rails/blob/3-1-stable/activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb#L231 cd `bundle show activerecord`

     Put a debugger statement when where the rollback is executed.
    /Users//.rvm/gems/ruby-1.9.3-/gems/activerecord-3.2.14/lib/active_record/connection_adapters/abstract/database_statements.rb

   196              transaction_open = false
   197              decrement_open_transactions
   198              if open_transactions == 0
   199                rollback_db_transaction
   200                debugger
=> 201                rollback_transaction_records(true)
   202              else
   203                rollback_to_savepoint
   204                debugger
   205                rollback_transaction_records(false)

When the rails server or console hits the breakpoint type in caller to get the backtrace.

3) Override AR in development mode. TODO: only override if !Rails.env.production? Put this in app/config/initializers/active_record_or_any_file_name.rb

ActiveRecord::Base.class_eval do
    alias_method :old_save, :save
    alias_method :old_save!, :save!
    def save(*args)
        begin
            puts "#{self} save"
            Rails.logger.info "#{self} save"
            old_save(*args)
        rescue Exception => e
            debugger
            puts e
        end
    end
    def save!(*args)
        begin
            Rails.logger.info "#{self} save!"
            puts "#{self} save!"
            old_save!(*args)
        rescue Exception => e
            debugger
            puts e
        end
    end
end