[Mondrian] RE: Mr. Hyde

[Julian Hyde]

I would use a debugger 

> -----Original Message-----
> From: Javier Giménez Aznar [mailto:javier.gimenez at stratebi.com] 
> Sent: Monday, June 04, 2007 5:34 AM
> To: mondrian at pentaho.org
> Cc: 'Julian Hyde'; 'Luis F. Canals'
> Subject: RV: Mr. Hyde
> 
> Hello Julian and everybody on the list,
> 
> We are trying to change mondrian code so it is able to manage 
> Internal Codes
> of members when referencing them with the "column" instead of with the
> "nameColumn". Making possible for example using [2007].&[2] instead of
> [2007].[February] to reference the member.
> 
> The problem seems to be around that ampersand &.
> 
> I seems that when parsing the MDX query, mondrian converts string like
> "[xxx].[yyyy].[zzzz]..." in arrays of strings like "[xxx]",
> "[yyy]", "[zzz]" and then back to a single string.
> 
> This happens in the clase Util. When changing the methods
> 
> 	lookup(..String[]..)
> for
> 	lookup(..Id.Segment[]..)
> 
> we have to change every class that uses them and we observe this weird
> behaviour that seems to cost time.
> 
> Our questions are.
> a) Wouldn't it be better to use Id.Segment instead of an 
> array of strings
> like "[xxx],[yyy]"?

You are absolutely on the right track. We should use Id.Segment in as
many places as possible.

> b) Where could the conversion of the MDX text to Is.Segment 
> be made? (we
> suspect watching the logs that in mondrian.olap.parser the
> mondrian.olap.query object is created with well identified 
> Id.segments, but
> somewhere before mondrian.olap.Util.lookup they are lost and 
> converted to
> String, so this seems to be already donde somewhere)

I would use a debugger, and put a breakpoint in Util.lookup. At some
point in the stack, the one data structure will turn into the other.

> And a more general question. Are we on the right path?

Yes, I think that not using Id.Segment is the root cause of the problem.

Before you start implementing a fix, I suggest that you add a test case
to ParserTest which will fail until you have correctly implemented a
solution.

Julian