Database Performance Monitoring on the Cheap Part 2

I was pretty happy to see that my last post "Database Performance Monitoring on the Cheap" got a bunch of hits on the intertubes. This somewhat balanced out my shame that the procedure I provided for querying the recorded data needed to be a bit smarter to be truly helpful.
Turns out that the stats provided by the sys.dm_os_performance_counters DMV are not all straightforward to interpret.
Some of them are either ratios (where one counter needs to be divided by another), or they are cumulative (where the counter needs to be compared to a previous value, and divided by the number of seconds elapsed).
Thankfully, there's an easy way to tell which counters are which, by checking the cntr_type field. When it comes to ratios, the numerator type is 537003264, and the denominator (or base) is 1073939712 (and has the word "base" at the end of the counter_name). The cumulative fellows are of type 272696576.

So without further ado, here's a smarter way to query that data which we've had collecting:

CREATE PROCEDURE [Monitoring].[sPerformanceCountersSelectByDateRange]
   @FormerDate DATETIME,
   @LatterDate DATETIME
         AS
   BEGIN
   SELECT
            DateTimeID
            ,DATETIME
            ,OBJECT_NAME
            ,counter_name
            ,instance_name
            ,cntr_value
            ,cntr_type
      FROM
      (
      SELECT
               DateTimeID
               ,DATETIME
               ,OBJECT_NAME
               ,counter_name
               ,instance_name
               ,cntr_value
               ,cntr_type
         FROM
               Monitoring.PerformanceCounters
         WHERE
               NOT PerformanceCounters.cntr_type IN (272696576,537003264,1073939712) --Cumulative and Ratio counters
         UNION
      SELECT --Cumulative Counters
               CurrentPerformanceCounters.DateTimeID
               ,CurrentPerformanceCounters.DATETIME
               ,CurrentPerformanceCounters.OBJECT_NAME
               ,CurrentPerformanceCounters.counter_name
               ,CurrentPerformanceCounters.instance_name
               ,(CurrentPerformanceCounters.cntr_value-PreviousPerformanceCounters.cntr_value)/
               DATEDIFF(ss,PreviousPerformanceCounters.DATETIME,CurrentPerformanceCounters.DATETIME) cntr_value
               ,CurrentPerformanceCounters.cntr_type
         FROM
               Monitoring.PerformanceCounters CurrentPerformanceCounters
               JOIN
               Monitoring.PerformanceCounters PreviousPerformanceCounters
               ON CurrentPerformanceCounters.counter_name = PreviousPerformanceCounters.counter_name
            AND CurrentPerformanceCounters.instance_name = PreviousPerformanceCounters.instance_name
            AND CurrentPerformanceCounters.DateTimeID
         = PreviousPerformanceCounters.DateTimeID
               + CASE RIGHT(CurrentPerformanceCounters.DateTimeID,2)
                  WHEN 00 THEN 45
         ELSE 5
         END
         WHERE
               CurrentPerformanceCounters.cntr_type = 272696576
         UNION
      SELECT --Ratio Counters
               NumeratorPerformanceCounters.DateTimeID
               ,NumeratorPerformanceCounters.DATETIME
               ,NumeratorPerformanceCounters.OBJECT_NAME
               ,NumeratorPerformanceCounters.counter_name
               ,NumeratorPerformanceCounters.instance_name
               ,NumeratorPerformanceCounters.cntr_value/CAST(DenominatorPerformanceCounters.cntr_value AS FLOAT) cntr_value
               ,NumeratorPerformanceCounters.cntr_type
         FROM
               Monitoring.PerformanceCounters NumeratorPerformanceCounters
               JOIN
               Monitoring.PerformanceCounters DenominatorPerformanceCounters
               ON DenominatorPerformanceCounters.cntr_type = 1073939712
            AND NumeratorPerformanceCounters.DateTimeID = DenominatorPerformanceCounters.DateTimeID
            AND NumeratorPerformanceCounters.instance_name = DenominatorPerformanceCounters.instance_name
         WHERE
               NumeratorPerformanceCounters.DATETIME BETWEEN @FormerDate 
            AND @LatterDate
            AND NumeratorPerformanceCounters.cntr_type = 537003264
      ) AllResults
      WHERE
            AllResults.DATETIME BETWEEN @FormerDate 
         AND @LatterDate
   END