Drop this file into config/initializers/ and enjoy SQL logging with stacktrace

activerecord.stack.rb

# set env FULL_STACKTRACE=1 for full stacktrace
# set env DEBUG_LOG=1 to turn this on (default off)

if defined?(ActiveRecord::LogSubscriber)
  module ActiveRecord
    class LogSubscriber
      def sql(event)
        self.class.runtime += event.duration
        return unless logger.debug?

        payload = event.payload

        return if IGNORE_PAYLOAD_NAMES.include?(payload[:name])

        name  = "#{payload[:name]} (#{event.duration.round(1)}ms)"
        sql   = payload[:sql]
        binds = nil

        unless (payload[:binds] || []).empty?
          binds = "  " + payload[:binds].map { |col,v|
            render_bind(col, v)
          }.inspect
        end

        if odd?
          name = color(name, CYAN, true)
          sql  = color(sql, nil, true)
        else
          name = color(name, MAGENTA, true)
        end

        app_path = Rails.root.join("app").to_s
        debug "#{Time.now.rfc822}  #{name}  #{sql}#{binds}; -- #{caller.join("\n")}" if ENV['FULL_STACKTRACE']
        debug "#{Time.now.rfc822}  #{name}  #{sql}#{binds}; -- #{caller.inject([]) {|sum,line| sum + (line.index(app_path) ? [line[app_path.length+1..-1]] : []) }[0..ENV['ACTIVERECORD_STACKTRACE_DEPTH'].to_i]}" unless ENV['FULL_STACKTRACE']
      end
    end
  end
end if ENV['DEBUG_LOG']