-# Copyright (c) 2005 Jamis Buck
-#
-# Permission is hereby granted, free of charge, to any person obtaining
-# a copy of this software and associated documentation files (the
-# "Software"), to deal in the Software without restriction, including
-# without limitation the rights to use, copy, modify, merge, publish,
-# distribute, sublicense, and/or sell copies of the Software, and to
-# permit persons to whom the Software is furnished to do so, subject to
-# the following conditions:
-#
-# The above copyright notice and this permission notice shall be
-# included in all copies or substantial portions of the Software.
-#
-# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
-# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
-# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
-# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
-# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
-# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
-# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
-module DeadlockRetry
- def self.append_features(base)
- super
- base.extend(ClassMethods)
- base.class_eval do
- class <<self
- alias_method :transaction_without_deadlock_handling, :transaction
- alias_method :transaction, :transaction_with_deadlock_handling
- end
- end
- end
-
- module ClassMethods
- DEADLOCK_ERROR_MESSAGES = [
- "Deadlock found when trying to get lock",
- "Lock wait timeout exceeded",
- "deadlock detected"
- ]
-
- MAXIMUM_RETRIES_ON_DEADLOCK = 3
-
- def transaction_with_deadlock_handling(*objects, &block)
- retry_count = 0
-
- begin
- transaction_without_deadlock_handling(*objects, &block)
- rescue ActiveRecord::StatementInvalid => error
- raise unless connection.open_transactions.zero?
- if DEADLOCK_ERROR_MESSAGES.any? { |msg| error.message =~ /#{Regexp.escape(msg)}/ }
- raise if retry_count >= MAXIMUM_RETRIES_ON_DEADLOCK
- retry_count += 1
- logger.info "Deadlock detected on retry #{retry_count}, restarting transaction"
- retry
- else
- raise
- end
- end
- end
- end
-end