SQL Server Analysis Services Introduction to Tabular Mode and BISM

Josh Fennessy

• BI Architect– BlueGranite, Inc (http://www.blue-granite.com)

Agenda

• Analysis Services – before today• The BI Semantic Model• Tabular Mode Architecture• Demonstration• Review / questions / comments

SQL SERVER ANALYSIS SERVICES

A brief history

SSAS’ story

• Based on OLAP technology purchased by MSFT from Panorama Software in ’96

• Officially released in ’98 as ‘OLAP Services’ in SQL 7.0

• Renamed in SQL 2000 to SSAS

• Many new features delivered in SSAS 2005– Data mining– UDM

ANALYSIS SERVICES TODAY

Broad adoption “Customers in the Magic Quadrant survey report that their Microsoft average deployment sizes are now larger than any other vendor in the survey in terms of users.”

“Use of OLAP functionality by Microsoft customers is more than double that for the rest of the survey respondents.”

Source: Gartner Magic Quadrant for BI Platforms, 2011

Highest rated infrastructure and development tools“Microsoft customers rate its BI platform infrastructure and development tools among the highest compared to other vendors, and a higher percentage of customers use them extensively.”

Source: Gartner Magic Quadrant for BI Platforms, 2011

Large ecosystem "Wide availability of skills is among the top reasons customers select Microsoft over competing vendors.”

Source: Gartner Magic Quadrant for BI Platforms, 2011

Analysis Services VisionBI Semantic

Model

Build on the strengths and success of Analysis Services and expand its reach to a much broader user base

Embrace the relational data model – well understood by developers and IT Pros

Bring together the relational and multidimensional models under a single unified BI platform – best of both worlds!

Provide flexibility in the platform to suit the diverse needs of BI applications

ANALYSIS SERVICES TOMORROW

Business Intelligence Semantic Model

BI SEMANTIC MODELOne Model for all End User Experiences

Client Tools Analytics, Reports, Scorecards,

Dashboards, Custom Apps

Data SourcesDatabases, LOB Applications, OData Feeds,

Spreadsheets, Text Files

BI Semantic ModelData model

Business logic and queries

Data access

Team BIPowerPivot for SharePoint

Personal BIPowerPivot for Excel

Organizational BIAnalysis Services

BI Semantic ModelWhat about existing Analysis Services applications?

New applicationsNew technology options

“Denali”

Existing applicationsBased on Unified Dimensional Model

Existing applicationsEvery UDM becomes a BI Semantic Model

Existing applicationsBased on Unified Dimensional Model

After RTM

BI Semantic Model

Data model

Business logic and queries

Data access ROLAP MOLAP VertiPaq DirectQuery

MDX DAX

Multi-dimensional

Tabular

Third-partyapplications

ReportingServices Excel PowerPivot

Databases LOB Applications Files OData Feeds Cloud Services

SharePointInsights

BISM ARCHITECTURE

BISM FEATURES

• Rich data modeling capabilities

• Sophisticated business logic using MDX and DAX

• Fine-grained security – row/cell level

• Enterprise capabilities – multi-language and perspectives

Richness• VertiPaq for high

performance, MOLAP for mission critical scale

• DirectQuery and ROLAP for real-time access to data sources

• State-of-the-art compression algorithms

• Scales to largest enterprise servers

Scalability• Multi-dimensional and tabular

modeling experiences

• MDX and DAX for business logic and queries

• Cached and passthrough storage modes

• Choice of end-user BI tools

Flexibility

SCENARIO: EXCEL OVER SALES MODEL

BI Semantic Model

Data model

Business logic and queries

Data access

SQL Server Dynamics CRM

EndUser Model Developer

MDX DAX

Multi-dimensional

Tabular

VertiPaq

WHAT DOES BISM DO FOR ME?Quiz time! Pick which one is a Tabular Model.

SSAS DATA ACCESS & STORAGExVelocity

In-memory column store… typical 10x compression

Brute force memory scans… high performance by default… no tuning required

Basic paging support… data volume mostly limited to physical memory

MOLAP Disk based store… typical 3x

compression Disk scans with in-memory subcube

caching… aggregation tuning required Extensive paging support… data

volumes can scale to multiple terabytes

DirectQuery Passes through DAX queries &

calculations… fully exploits backend database capabilities

No support for MDX queries… no support for data sources other than SQL Server (in Denali)

ROLAP Passes through fact table requests…

not recommended for large dimension tables

Supports most relational data sources… no support for aggregations except SQL Server indexed views

CUSTOM CALCULATIONS

DAX Based on Excel formulas and

relational concepts – easy to get started

Complex solutions require steeper learning curve – row/filter context, Calculate, etc.

Calculated columns enable new scenarios, however no named sets or calc members

MDX Based on understanding of

multidimensional concepts – higher initial learning curve

Complex solutions require steeper learning curve – CurrentMember, overwrite semantics, etc.

Ideally suited for apps that need the power of multidimensional calculations – scopes, assignments, calc members

HOW SHOULD I BUILD MY SSAS SOLUTION?

Two Visual Studio (BIDS) project types in Denali Multidimensional project – with MDX and MOLAP/ROLAP Tabular project – with DAX and VertiPaq/DirectQuery

Some Considerations

• Cube write-back needed?• Parent/Child needed?• 4/4/5 Fiscal Calendars• Excessive Many to Many• Extreme data volumes• Large MD investment?• Large RAM footprint a negative?• Financial models

(budgeting/forecasting)

• Real-time (Direct Query)• Counting what’s not present• Excel-based Modeling Attractive?• Non-relational data sources?• In-memory performance benefit• Lower learning curve desirable?• Simpler models (Sales, OLTP

transaction analysis, etc.)

Favors Multi-dim/MDX Favors Tabular/DAX

OTHER THOUGHTS… Multidimensional isn’t dead

DAX doesn’t address some common modeling requirements Vertipaq has more limited storage (models must fit in RAM) Many simple data modeling tasks are easier in DAX; many complex ones

are easier in MDX As DAX/BISM evolves it will close the gap, but not for a couple years

At RTM Power View is a Tabular-only technology This will probably force a decision to tabular in some scenarios

Business Analytics is complex no matter what expression language is used DAX isn’t a silver bullet, but it probably is easier to learn to implement

basic/intermediate calculations than MDX for those new to OLAP Should I port my Multidimensional cube to Tabular during migration?

If calculations aren’t complex and all necessary features are available in Tabular Mode/DAX, you should consider doing so to achieve better performance and Power view support

If the existing calculations and installed

OTHER THOUGHTS… Process for Multidimensional to Tabular migration

Evaluate features in the gap Many-to-many (can be done in calculations however) Parent/Child Cube writeback Calculated members Etc.

How difficult to rewrite calculations in DAX? Is the data too large for Tabular mode? (terabytes+) Will the server have enough RAM? Existing application impact? Does Tabular/DAX solve unmet needs?

Multi-select issues in calculations Counting what’s not there needs Performance issues (ad-hoc w/o aggregation issues)

Demo

REVIEW• BISM is designed to make USER experience smoother

• Complexity still exists in data modeling

• Multi-dimensional is not gone

• DAX is still complex

THANK YOU!Questions? Email me - jfennessy@blue-granite.com