                         g = (err, x) ->
                             that._concurrent_queries -= 1
                             clearTimeout(warning_timer)
+                            clearTimeout(error_timer)
                             report_time = ->
                                 tm = new Date() - start
                                 @_stats ?= {sum:0, n:0}

            driver   : 'native'    # dash or native
            pool     : 40          # number of connection to use in connection pool with native driver
            warning  : 15          # display warning and stop using connection if run takes this many seconds or more
            concurrent_warn : 500  # if number of concurrent outstanding db queries exceeds this number, put a concurrent_warn message in the log.
            cb       : undefined
        dbg = @dbg('constructor')

        @_database         = opts.database
        @_num_connections  = opts.pool
        @_warning_thresh   = opts.warning
        @_error_thresh     = opts.error
        @_concurrent_warn  = opts.concurrent_warn

        if typeof(opts.hosts) == 'string'
