[Mondrian] IgnoreMeasureForNonJoiningDimension

Matt Campbell mkambol at gmail.com
Mon Feb 25 11:09:25 EST 2013


I've created MONDRIAN-1457 for the bug I mentioned at the bottom of my last
email.  On Friday I committed a fix to IgnoreMeasureForNonJoiningDimension
tests in 4.0.  I think it will still be worth considering removing the
functionality if no one is using it.  Unlike the similarly named
IgnoreUnrelatedDimensions,
there's no precedent for IgnoreMeasureForNonJoiningDimension in other OLAP
engines, and it seems more likely to cause confusion than anything.



On Thu, Feb 21, 2013 at 6:14 PM, Matt Campbell <mcampbell at pentaho.com>wrote:

> This afternoon I started working on a task to fix some failing tests on
> lagunitas involving the  IgnoreMeasureForNonJoiningDimension property
> (MONDRIAN-1437).  Despite having been involved in the original request for
> this feature, it took me a little while to wrap my head back around the
> functionality.  ****
>
> ** **
>
> Here’s my memory of the use case that prompted my former employer to push
> for this a few years back.  With healthcare data, analysts may want to sum
> up claims data that’s coming from different sources.  For example, [Net
> Payment] is defined as the sum of payments from the Drug Claims cube and
> payments from the Hospital Claims cube.  These two cubes have very similar
> but not identical dimensionality.****
>
> ** **
>
> Our users would create reports with a dimension that joins to one but not
> both of these two cubes, and then be very surprised at the totals.  In the
> example below the [Drug] dimension does not join to the Hosp cube:****
>
> ** **
>
> *Drug *
>
> *Net Payment*
>
> *Net Pay Drug*
>
> *Net Pay Hosp*
>
> FLECAINIDE ACETATE ****
>
> 758.79****
>
> 758.79****
>
> ** **
>
> MAXAIR AUTOHALER ****
>
> 1,689.79****
>
> 1,689.79****
>
> ** **
>
> MENOSTAR ****
>
> 1,482.10****
>
> 1,482.10****
>
> ** **
>
> NITROGLYCERIN ****
>
> 766.60****
>
> 766.60****
>
> ** **
>
> PROVENTIL AEROSOL ****
>
> 609.48****
>
> 609.48****
>
> ** **
>
> *TOTAL*
>
> 11536.24****
>
> 5306.76****
>
> 6229.48****
>
> ** **
>
> Since the total would be defined with [Drug].[All Drug], the [Net Pay
> Hosp] column ends up with an odd looking number, and the [Net Payment]
> column does not seem to add up correctly.  Easy to explain to someone
> versed in MDX, not so easy to explain to the typical analyst.****
>
> ** **
>
> Enter IgnoreMeasureForNonJoiningDimension.  The thought was that we needed
> something essentially the opposite of ValidMeasure or
> IgnoreUnrelatedDimensions.  ValidMeasure forces unrelated dimensions to the
> All level.  We needed something that would cause evaluation to be null even
> if the unrelated dimension *was* at the All level.  I worked with a
> developer from ThoughtWorks to get this enhancement in and passing cases
> with Cognos generated MDX.****
>
> ****
>
> We used this functionality briefly before hitting enough other border
> cases around totals that we moved to an alternative fix involving more
> complex Cognos report specs. ****
>
> ** **
>
> I’m curious now whether anyone else is using this functionality.  If you
> are, it would be good to hear your use cases so we make sure they’re
> accounted for in 4.x.  If no one is using it, it seems like a potential
> candidate for the chopping block.****
>
> ** **
>
> As I’ve been poking at it today, I’ve noticed some things that seem broken
> even in Mondrian 3.x.  For example, with
> IgnoreMeasureForNonJoiningDimension enabled, the following two queries give
> different results in 3.x.  The first ignores the measure with the
> non-joining Gender dimension and returns null, the second query returns
> 196,770.888.****
>
> ** **
>
> WITH MEMBER [Measures].[memberArrayValueCalc] as ****
>
>   '( measures.[warehouse sales], [Gender].[All Gender], [Product].[All
> Products] )'****
>
> SELECT ****
>
>    [Measures].[memberArrayValueCalc] on 0 ****
>
> FROM ****
>
>   [warehouse and sales]****
>
> ** **
>
> ** **
>
> SELECT ****
>
>   ([Measures].[warehouse sales], [Gender].[All Gender], [Product].[All
> Products] ) on 0 ****
>
> FROM ****
>
>   [warehouse and sales]****
>
> ** **
>
> ** **
>
> ** **
>
> ** **
>
> ** **
>
> _______________________________________________
> Mondrian mailing list
> Mondrian at pentaho.org
> http://lists.pentaho.org/mailman/listinfo/mondrian
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.pentaho.org/pipermail/mondrian/attachments/20130225/8547e0a6/attachment.html 


More information about the Mondrian mailing list