If you have been following the PASS summit notes coming from the attendees, you would have noticed an unmatched sense of pandemonium in the SSAS community. The reason is none other than the announcement of Microsoft’s decision to move from the traditional multidimensional SSAS database to the new in-memory Vertipaq BISM. My first source of this news was from Chris Webb’s blog – PASS Summit Day 2 and after reading it, I was in a state of shock for quite some time. It seemed hard to digest that Microsoft could be doing this to one of their most successful tools in the market. This could have been aggravated by the realization that one of my core skills was going to get obsolete and the hesitation or resistance to change from my comfort zone. Even Teo Lachev seemed to mirror the moderate disappointment that seemed to be floating around in Chris’ writeup in his own blog – The Battle of the Models. It wasn’t disappointment everywhere as experts like Boyan Penev (Thoughts on BISM, SSAS and MDX) and Siddharth Mehta (SQL Server Denali – Boost to SSIS career, Start of End to SSAS and MDX career?) have tried to find reason with this development and at least my understanding is that they are more on the happier side. After this feeling had finally sunk in, I decided to write a pre-mature obituary for one of my favourite tools in my company’s technology page as given below:- “ Is it the end of the road for Microsoft SQL Server Analysis Services? It certainly seems so, Microsoft has dealt a deathblow to the multidimensional approach of OLAP and has announced in today’s PASS summit that it’s focus is on a newer and less multi-dimensional approach – the BI Semantic Model. The BISM – BI Semantic Model – is the name for the new type of Analysis Services database that gets created when you publish a PowerPivot model up to the server. This is clearly a strategy to bring in more ROLAP experts to the tool as the popular perception is that the learning curve for SSAS is pretty steep and many people are put off by it. What it means is that while the MOLAP SSAS won’t be deprecated, the efforts of the SSAS dev team are concentrated on BISM and PowerPivot and we shouldn’t expect any radical new changes for the future. This could mean a gradual death for SSAS by 2012 once Project Denali (which is expected to be renamed as SQL Server 2011, and rumored to be released in the last quarter of 2011) is released and established commercially. So, welcome DAX and bye MDX.” 
Why I termed this as pre-mature is because a new comment has appeared in Chris Webb’s blog from Amir Netz (Lead Architect for Microsoft’s BI offering) and it seems to be promising. Some excerpts from that
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BISM and VertiPaq are all new features of SSAS. SSAS is gaining massive new capabilities in Denali. Nothing it taken away, nothing is deprecated. It is all net positive. I hope you can not only internalize it but also communicate it to others.
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The best way I think of the relationship of the “MOLAP UDM” to the “VertiPaq BISM” is akin to the relationship between C++ and C# in the year 2000. While C++ will still stay with us forever, C# is advancing rapidly and is able to take on broader and broader workloads. And the most important thing, Visual Studio – offering both C++ and C# is a much better product then the one offering only C++. It offers developers the option of choosing the right tool for the right task. Now – replace C++ with MOLAP UDM, C# with “VertiPaq BISM”, and Visual Studio with “SSAS” and you got the exact situation of today.
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Even with VertiPaq BISM introduced, MOLAP UDM is still used for all the high end heavy lifting and it is just as important as it had always been.
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As for the roadmap – MOLAP is here to stay. It will have new features every release (just like we have new important MOLAP features in Denali). Yes – BISM being less mature will see a faster innovation pace and being based on a more innovative foundation it will likely be the one creating exciting breakthroughs as we move forward.
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We worked hard to preserve the investments you made in the UDM and MDX. For example, the BISM supports ODBO and MDX. In fact – this is the only way Excel connects to it. All of the MDX lovers can still send MDX queries and create calculated members in the BISM. This is how Panorama works with the PowerPivot model. AMO works with the BISM as well as with the UDM. etc. Make no mistake about it – MOLAP is still the bread and butter basis of SSAS, now and for a very long time. MDX is mature, functional and will stay with us forever.
Yippee! Again, if I can trust my sense of understanding things, it would mean all is not lost and SSAS is here to stay. I guess I would have to wait for another blog from Chris to completely enlighten common people like me and allay my fears. Till then, I would recommend you guys to go and read Amir’s comments completely in Chris’ blog. And definitely, don’t miss out on the other great blog links that I have given. Update (13/11/2010) Microsoft has come out with an official reply now in the SQL Server Team Blog – Analysis Services – Roadmap for SQL Server “Denali” and Beyond. The blog has tried to put out the fears by underlining that the new BISM model does not replace the traditional UDM model. This is also evident from the model diagram they have posted (given below also) where we can see the relational and multidimensional data models existing side by side. 
Some salient points of the blog are:-
- While PowerPivot is targeted at business users to build Personal and Team BI applications, Analysis Services is the platform for building Professional BI applications.
- With the introduction of the BI Semantic Model, there are two flavors of Analysis Services – one that runs the UDM (OLAP) model and one that runs the BISM model. This is a side-by-side offering – you can choose to run one instance of Analysis Services hosting a UDM model and another instance hosting a BISM model on the same server.
- You might ask – Why do we have two types of models in Analysis Services? Which one should I use? Is the UDM going to be deprecated now that we have the BISM? The answer is NO! Analysis Services just got a lot better in SQL Server “Denali” with the BISM and VertiPaq and DAX! However the UDM is a mature and industry leading technology and is here to stay.
- Some existing UDM applications that are undergoing a major overhaul might be migrated to run on the BISM if appropriate. For new BI applications, the choice between UDM and BISM will depend on the complexity of the application. For BI applications that need the power of the multidimensional model and sophisticated calculation capabilities such as scoped assignments, the UDM is the way to go. For a broad majority of BI applications that don’t need that level of complexity, the BISM will offer a rich, high performance platform with faster time to solution
- The Analysis Services team is committed to staying on the cutting edge of BI innovation and leading the industry with breakthrough technologies such as VertiPaq. At the same time, we recognize our rich heritage in OLAP and continue to be humbled by success of our product and the vast ecosystem of customers and partners that it has helped us build.
So this blog from Microsoft should answer the question which we asked, the answer – SSAS is here to STAY!
Hey..Thnx Jason for this Post..