updating the MOLAP/ROLAP state

[csmba]

I have a cube, with few partitions (the ones that are created automatically,
nothing I made), and few dimensions.

I want to change it to ROLAP (currently MOLAP). I notice I can go in the
management studio and change each partition individually, and the cube, and
the dimensions... but that means about 11 individual changes (click
properties, change the thing, save...) isn't there an easier way to just
say: change everything to ROLAP ??

thanks

 

[johnherman]

I don't think so. The concepts of MOLAP, ROLAP, and HOLAP are quite significant and affect storage, precalcuations and aggregations, performance, etc.

MOLAP, having precalculated aggregations, is has faster query times but takes longer to build.

ROLAP, which has no precalculated aggregations, is fastest to build but takes longer to query. ROLAP is also used for Real-Time and Near-Real-Time data analysis.

HOLAP is a "Hybrid" between ROLAP and MOLAP

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The trouble with doing something right the first time is that nobody appreciates how difficult it was - Steven Wright

 

[csmba]

thanks.
I understand the differences, that is why I thought I should have a system set up as ROLAP at first, when the database starts fresh, and then transform it into MOLAP as the database gets bigger... but I thought there will be an easy way of doing so, without manually going partition by partition, dimension by dimension, and changing it.

why would it make sense to have some partition/dimensions set to MOLAP, and some to ROLAP (or MOLAPs with different delay settings)? wouldn't that make the data coming back from reports inconsistence? how can you trust data that comes from an underlying source that was built using different snapshots in time?

thanks

 

[johnherman]

If you have some static partitions (let's say you are partitioning by time) and some active partitions, it would be useful to have the static ones (say last year) be MOLAP while current month would be much better as ROLAP.

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The trouble with doing something right the first time is that nobody appreciates how difficult it was - Steven Wright

 

[csmba]

but how do you define the partition to be "current month"? I thought about it, but my partitions are per table. how do I create 2 partitions based on the same table, one being "last X time" and the other being "the rest" ?
and how do I do it so it is automatic? so that I don't need to change the partition definitions daily or monthly?

 

[MDXer]

how do I create 2 partitions based on the same table

Use a view with a where clause that returns only the data defined in that partition.

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