I cant find anything on what new features come out with SSAS 2017 for a multidimensional database. the only thing i can find is updates with the Tabular.
any insight would be appreciated.
SSAS 2017 is primarily focused on new tabular features. There is a new compatibility level for tabular (1400) but no new compatibility level for multidimensional.
There are several discontinued and deprecated features, mainly for the multidimensional mode, and the default mode when installing is tabular now.
Related
We have VS 2019 for SSAS development (with installed SSDT).
I would like to create aggregations for measures in order to increase query performance (cube with tabular model).
Could you tell, please, where the window "Aggregation" is located in VS?
P.S. on the screen you can see a snapshot from the video on youtube where i highlighted the ribbon (and button) i am searching for.
From the screenshot, it looks like, You are looking into a video on SSAS (multi dimensional). It is having aggregations. For SSAS (Tabular), there are no custom aggregations.
You can see the difference between SSAS (multidimensional) Vs SSAS (Tabular) here
Feature
Multidimensional
Tabular
Aggregations
Yes
No
I was googling about "How does SSAS Multidimensional works?" but unfortunately couldn't get any related post.
Basically my question is how does it's engine works and why it works faster than the SQL server database. I actually want to know the backend of it's engine.
Please help me with the links or post to get the brief knowledge about it's evaluation context.
I've been working on SSAS tabular model since last around one year now I've got a projects where in I've to develop a Multidimensional Model.
Thanks in Advance.
I hope you are doing well.
I'm working on a migration from an on premise ssas multidimensionnal cube to an azure analysis services tabular model.
Is there a way , a method or a tool to do it quickly and efficiently?
It's a large cube and it will take time to develop it from scratch with tabular model.
Thank you for your help
SSAS Multi Dimensional (MD) and Tabular are fundamentally different technologies, there is no quick method of converting one to the other, you will have to rebuild the model from scratch, and the measures etc.
Be aware that some of the things MD models are good at, like calculating up and down hierarchies, Tabular really struggles with. If the cube is fundamentally sound and has good performance, and you want to move it into the cloud service, use a VM in Azure, with SQL Server on it, it may work out cheaper that Azure AS, per month.
We know that over a decade ago with very limited compute power and storage available, the invention of multi-dimensional model (cube) was to solve the above problem, e.g.SSAS. However with recent cloud technology advancement, compute power and storage are cheap, I struggle to see the point of using multi-dimensional model (cube,) in a enterprise business analytic solution?
Anyone has any other thoughts to share please?
Thank you.
Per my opinion the greatest advantage of having SSAS model in an enterprise business analytic solution is that the end user can connect to it through Excel and just drag and drop measures and dimensions and create all kinds of useful reports with all kinds of calculations that are built in the cube (year to date, rolling 12, etc...), and without this model, they will have to rely on relational database to create much of complicated SQL calculations on their own, and first of all they will have to know SQL in details to do this, so they will probably have to rely on some kind of IT stuff to help them on daily basis to do this.
In SSAS, besides multidimensional there is also a tabular model, but the answer would be the same.
I was wondering if anyone here knows the exact differences for these 2 modes, more specifically:
What can we do in one model that we can't do with the other? (Multi-dimensional vs Tabular and vice versa)
How is the data stored in one model versus another?
If I am wring an SSRS / PowerBI / Excel report against this, what limitations does one model have over the other?
Does the tabular model have cubes? If not, what is the alternative storage medium and how does it differ from cubes (maybe provide for me
some background on what cubes are to begin with)
What are the differences in security considerations? As I understand, with the Multi-dimensional model, row-level, column, level
and even cell-level security can be applied - what is available with
this for the tabular model?
Also, as I understand SQL Server 2016 is moving to using the Tabular Model by default and that there may be some differences/improvements
over what is current in use (SQL Server 2014) - can you please provide
a list of what those are?
Thank you so much in advance.
A good place to start might be these articles which should be accurate as to the differences in SSAS 2014.
Advice on the decision points for choosing to build a Tabular or Multidimensional model
Paul Turley’s high-level description of Tabular strengths and weaknesses
Dimension relationships
Summary level presentation
Many-to-many relationships and writeback and scope statements and non-visual dimension security are some of the biggest missing features in SSAS 2014 Tabular in my opinion.
Tabular security is row based and just supports visual totals, not non-visual totals or cell security. But in many cases you don't want to use cell security for performance reasons.
Tabular uses in-memory columnar storage. Multidimensional uses disk-based row-based storage. So scanning a billion row fact table requires reading all columns from disk in Multidimensional and takes a minute or two to return a query on a fact table that large. If you optimize the Multidimensional model by building an aggregation then the query may take seconds. Tabular just scans the columns used in the query and simple queries or calculations even on a billion row table may return in under a second.
With SSAS 2016 Tabular the bidirectional relationship was added which was a very big deal for modeling flexibility and allowing many-to-many relationships. And parallel partition processing made loading large models feasible.
SQL 2017 installer for SSAS has Tabular as the default.
If you have the option for using SSAS 2016 Tabular or above it is highly recommended for performance and modeling flexibility. Here is what's new in SSAS 2016 and SSAS 2017.