Ticket #5457: nested_transactions.rb

class ActiveRecord::ConnectionAdapters::PostgreSQLAdapter
  alias begin_db_transaction_unnested begin_db_transaction
  alias commit_db_transaction_unnested commit_db_transaction
  alias rollback_db_transaction_unnested rollback_db_transaction

  def begin_db_transaction
    @nested_transaction_count ||= 0
    if @nested_transaction_count > 0
      #puts "starting savepoint #{@nested_transaction_count}"
      execute "SAVEPOINT rails_nested_transaction_#{@nested_transaction_count}"
      @nested_transaction_count += 1
    else
      #puts "starting transaction #{@nested_transaction_count}"
      begin_db_transaction_unnested
      @nested_transaction_count = 1
    end
  end

  def commit_db_transaction
    if @nested_transaction_count > 1
      @nested_transaction_count -= 1
      #puts "releasing savepoint #{@nested_transaction_count}"
      execute "RELEASE SAVEPOINT rails_nested_transaction_#{@nested_transaction_count}"
    else
      @nested_transaction_count = 0
      #puts "committing transaction #{@nested_transaction_count}"
      commit_db_transaction_unnested
    end
  end

  def rollback_db_transaction
    if @nested_transaction_count > 1
      @nested_transaction_count -= 1
      #puts "rolling back to savepoint #{@nested_transaction_count}"
      execute "ROLLBACK TO SAVEPOINT rails_nested_transaction_#{@nested_transaction_count}"
    else
      @nested_transaction_count = 0
      #puts "rolling back transaction #{@nested_transaction_count}"
      rollback_db_transaction_unnested
    end
  end

end