[Mondrian] SOLVE_ORDER: AS2K vs. SSAS2005

Matt Campbell mkambol at gmail.com
Fri Mar 28 09:23:39 EDT 2008


Sorry, the example was not clear--the solve order of the cube member is
actually higher.  So [Store Sales Ratio] has a solve_order greater than 10,
and gets evaluated after the Time.[Difference] in AS2K and Mondrian.

With SSAS2005 the cube calculated members are evaluated first by default,
regardless of relative solve_order, which means Time.[Difference] is
evaluated after [Store Sales Ratio].

On Fri, Mar 28, 2008 at 1:15 AM, Benny Chow <bchow at lucidera.com> wrote:

> If the query in your blog does to evaluate the query calculated member
> with solve order 10 before the schema defined member with solve order 0,
> then looks like a problem with AS2K.  Are you sure the results are correct?
> I ran your query in Mondrian and got 0 for the difference cell value which
> is the expected behavior when you evaluate the difference calculated member
> first.
>
> Benny
>
>
> ------------------------------
>  *From:* mondrian-bounces at pentaho.org [mailto:mondrian-bounces at pentaho.org]
> *On Behalf Of * Matt Campbell
> *Sent:* Friday, March 28, 2008 4:30 AM
> *To:* Mondrian developer mailing list
> *Subject:* [Mondrian] SOLVE_ORDER: AS2K vs. SSAS2005
>
> I've had a persistent headache over the past several months trying to deal
> with solve order related issues.  We have limited control over the MDX
> generated by our reporting tool (Cognos), which means that in some cases the
> solve order of calculated members in the query is incorrect relative to
> the solve order of cube members.
>
> While this is a problem with Cognos, it is really a general issue with any
> reporting client.  Since the client can't really guess what the solve
> order of measures in the cube is, let alone what the user intends with a
> particular calculation, there is always the possibility of conflict.  A tool
> can allow specifying absolute solve order, but that means the user
> creating the report needs to know and understand details about cube
> definition that they may not have access to.
>
> Recently I've learned more about how SSAS2005 handles solve order.
> SSAS2005 uses a model where solve order is given a scope.  Members within
> the cube are by default evaluated before members in the query, regardless of
> relative solve order.  In almost all cases this makes better sense.  For
> the times when it doesn't SSAS allows you to specify SCOPE_ISOLATION=CUBE
> for a particular member to allow the AS2K behavior.  I did a write up of the
> differences at
> http://777eisenhower.blogspot.com/2008/03/analysis-services-2000-vs-2005.htmlif anyone is interested.  The SSAS 2005 behavior seems like it would
> eliminate most of the problems we've had.
>
> Has anyone else run into similar problems with solve order?  I'm planning
> on creating some unit tests which demonstrate the SSAS 2005 behavior, and
> hopefully this can eventually be rolled into Mondrian.
>
>
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