Microsoft SSAS: Should I use Tabular or Multidimensional?

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Choosing the right version, tabular or multi-dimensional, of Microsoft SQL Server Analysis Services is key because once you start developing, you will not be able to easily "migrate" the work to the …

Choosing the right version, tabular or multi-dimensional, of Microsoft SQL Server Analysis Services is key because once you start developing, you will not be able to easily "migrate" the work to the other version. (You pretty much need to start over.) During this presentation, Senturus discusses how to choose between the tabular and multi-dimensional versions of SSAS for your analytic needs and the various features and benefits that each version provides.

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  • 1. 1Helping Companies Learn From the Past, Manage thePresent and Shape the Futurewww.senturus.comMicrosoft SSAS: Should I use Tabularor Multidimensional?
  • 2. 2This slide deck is part of a recorded webinar.To view the FREE recording of this entirepresentation and download the slide deck, go tohttp://info.senturus.com/2013-05-16-Microsoft-SSAS.htmlThe Senturus library has over 90 other recorded webinars,whitepapers, and demonstrations on assorted business intelligencetopics which may interest you.Go to the recorded resources
  • 3. 3Agenda• Introductions• Company Overview• Overview and History of SSASMultidimensional and Tabular• Technical comparison of the twoversions• Summary Recommendations• Further Resources• Q & A
  • 4. 4Presenters TodayGreg HerreraCo-FounderCEODavid Shroyer• Over 12 years experienceimplementing BI solutions withthe Microsoft stack• Worked for ProClarity, which waslater purchased by Microsoft• Started “cube building career”with Arbor Essbase.• MBA
  • 5. 5Who is Senturus ?• Consulting firm specializing in Corporate PerformanceManagement– Business Intelligence– Tools of the Office of Finance• Enterprise planning & budgeting• Consolidate, close, report and file (CCRF)– San Francisco Business Times Hall of Fame -- Fourconsecutive years in Fast 100 list of fastest-growingprivate companies in the Bay Area• Experience– 13-year focus on performance management– More than 1,200 projects for 650+ clients• People– Business depth combined with technical expertise.Former CFOs, CIOs, Controllers, Directors...– DBAs with MBAswww.Senturus.com 888.601.6010 info@senturus.com
  • 6. 6A few of our 650+ Clients
  • 7. 7SSAS Multidimensional• MSOLAP debut with the release of SQLServer 7.0• The technology was purchased from anIsraeli company Panorama• It quickly became one of the most usedOLAP engines, primarily because it wasincluded in the SQL Server suite andthere was no additional cost
  • 8. 8SSAS Multidimensional• SSAS was completely overhauled withthe release of SQL Server 2005• This new version allowed for “subcubes” with the Scope statement. Thisradically increased the functionality ofthe cubes• SSAS 2008R2 and 2012 have primarilybe concerned with query performanceand scalability
  • 9. 9PowerPivot• With the release of Excel 2010 came anadd-in called PowerPivot• PowerPivot uses a local instance ofAnalysis Services with the new xVelocityengine• The xVelocity in memory engine cangreatly increase query performance
  • 10. 10SSAS vs PowerPivot• PowerPivot is a client based tool. Alldata is stored in the Excel workbooks.• PowerPivot does not have any security,other than securing a workbook on thefile system• Microsoft position PowerPivot as “Self-Service BI” whereas SSASMultidimensional is “Corporate BI”
  • 11. 11SSAS Tabular• With the release of SQL Server 2012came the “server version” of PowerPivotwhich is a “tabular” instance of SSAS onthe server• Models can be created directly on theserver or PowerPivot models can beimported
  • 12. 12This slide deck is part of a recorded webinar.To view the FREE recording of this entirepresentation and download the slide deck, go tohttp://info.senturus.com/2013-05-16-Microsoft-SSAS.htmlThe Senturus library has over 90 other recorded webinars,whitepapers, and demonstrations on assorted business intelligencetopics which may interest you.Go to the recorded resources
  • 13. 13Languages• Multidimensional cubes use MDX forcalculations, security, and queries• Tabular uses DAX for calculations andqueries. It is also MDX compliant,which means that MDX based tools, likeExcel, can query Tabular cubes
  • 14. 14Multidimensional Modeling• Based on a traditional star schemamethodology. This includes dimensiontables and fact tables. (Kimballmethodology)• Multidimensional models can includeadvanced calculations and sophisticatedbusiness logic.
  • 15. 15Tabular Modeling• Organizes data into related tables• Because tables do not need to bedesignated as “dimensions” or “facts”the development time is less withtabular because all related tables serveboth roles
  • 16. 16Data Model Considerations• One criteria to use when making thechoice between versions is to look atyour data warehouse data model. Therelationships and characteristics of thedata can help guide you to the properproduct
  • 17. 17Data Considerations• One to Many Relationships– Both models handle these out of the box.Although with tabular you can only join onONE field• Many to Many Relationships– Multidimensional handles this out of thebox. Tabular does not allow for M2Mrelationships but you can “work around it”by using DAX calculations
  • 18. 18Hierarchies• Standard Hierarchies– Multidimensional needs to have hierarchyattribute relationships to be defined. Thecube then uses those hierarchies to pre-calculated “totals” at those levels– Tabular does not need any definedrelationships. Because it is “in memory”there is no need for pre-calculatedaggregations
  • 19. 19Hierarchies• Ragged Hierarchies– Multidimensional provides support forragged hierarchies by hiding any missingvalues in the hierarchy– Tabular does not support raggedhierarchies
  • 20. 20Hierarchies• Parent/Child Hierarchies– Multidimensional allows for parent/childhierarchies out of the box. These are useful forsupervisor/employee dimensions as well a chart ofaccounts dimension– Tabular does not support the definition of parent-child hierarchies; however, the DAX languageprovides a set of functions that allows users toexplore parent-child hierarchies and to use thesehierarchies in formulas.
  • 21. 21Financial Hierarchies• Unary Operators– Multidimensional offers out of the box support forunary operators. This is very important for chartof account hierarchies– Tabular does not support unary operators• Semi-additive Measures– Multidimensional has built in aggregation functions– Tabular handles these measures but you need touse separate DAX functions for each level such asClosingBalanceMonth
  • 22. 22This slide deck is part of a recorded webinar.To view the FREE recording of this entirepresentation and download the slide deck, go tohttp://info.senturus.com/2013-05-16-Microsoft-SSAS.htmlThe Senturus library has over 90 other recorded webinars,whitepapers, and demonstrations on assorted business intelligencetopics which may interest you.Go to the recorded resources
  • 23. 23Additional Features• Perspectives – available in both models• Translations – only available withmultidimensional• Actions – only available in multidimensional• Drillthrough – available in both models• Write-back – only available inmultidimensional• Role Playing Dimensions – not available inTabular
  • 24. 24Additional Features• Formatting Measures – Tabular doesnot allow for custom formatting• Display Folders – Tabular does notallow for display folders• Naming the All Level – Tabular does notallow for the naming of the All Level
  • 25. 25Calculations• Both models have a wide variety ofcalculation possibilities• Multidimensional allows for extracalculation properties such as font colorand background color based on logic• Multidimensional allows for calculationsthat are not located on the measuresdimension
  • 26. 26Shell Dimensions• In multidimensional you can create“shell dimensions” which can store“global” calculations• This is often used for Date Calculationssuch as year over year variances andYTD• These can also be used for unit ofmeasure conversions and other globalcalculations
  • 27. 27Date CalculationsAdding a date calculations dimension to a cube canmake creating dashboard type reports very easy
  • 28. 28Date Calculations• With tabular you have two choices– You build your date calculations into themeasures dimension – Qty, Qty LY, Qty LYVar, Qty LY Var %, Sales, Sales LY, etc– Or you create a faux shell dimension and includemassive nested IIF statements to trap for everypossible intersection. (which is just notreasonable) This also causes problem in that youcan only format a measure so shell dimensions arejust not suited for Tabular
  • 29. 29SSAS Advanced Course• In case you are interested in learning how to useshell dimensions and create a date calculationsdimension, in multidimensional, we have anupcoming class which teaches these concepts
  • 30. 30MDX vs DAX• MDX (Multi-Dimensional Expressions) is usedin Multidimensional and it is a language ofhierarchies and dimensions• DAX (Data Analysis Expressions) is used inTabular and it is more columnar based• One of the reasons why Microsoft investedheavily into the xVelocity technology wasbecause they felt that MDX was too difficultfor the average DBA
  • 31. 31MDX vs DAX• MDX can be hard to conceptualize but ithas the advantage of being able tonavigate hierarchies• Percent of Parent calculation in MDX[Measures].[Sales Amount] /([Product].[Product Categories].CurrentMember.Parent,[Measures].[Sales Amount])
  • 32. 32MDX vs DAX• Here is the Percent of Parent calculationin DAXIF(ISFILTERED(Product[Product]),[Sales]/CALCULATE([Sales],ALL(Product[Product])),IF(ISFILTERED(Product[Subcategory]),[Sales]/CALCULATE([Sales],ALL(Product[Subcategory])),1))
  • 33. 33This slide deck is part of a recorded webinar.To view the FREE recording of this entirepresentation and download the slide deck, go tohttp://info.senturus.com/2013-05-16-Microsoft-SSAS.htmlThe Senturus library has over 90 other recorded webinars,whitepapers, and demonstrations on assorted business intelligencetopics which may interest you.Go to the recorded resources
  • 34. 34Named Sets• In multidimensional named sets allowyou to retrieve common sets ofmembers that can be used in reporting,such as “current day”, “current month”,or “last 12 months”• Named sets are not available in Tabularbut you can duplicate some of theirfunctionality using attributes and sqldate functions
  • 35. 35Named Sets• Named sets are critical for automatingdate selection in dashboards• Named sets will also be covered in ourSSAS Advanced Topics course
  • 36. 36Data Storage• Multidimensional stores data in datapartitions and then it createsaggregations within the partitions– Compression is normally 3X to 4X• Tabular loads data into memory sothere is no need for aggregations– Compression is normally 10X
  • 37. 37Scalability• Multidimensional can scale to billions ofrecords. This is accomplished throughthe use of data partitioning• Tabular is limited by the amount ofmemory on the server– The lower the cardinality of the data themore records can be fit into memory
  • 38. 38Processing Performance• Multidimensional has dependencieswhich can make cube processingsomewhat tricky– All dimensions must be processed beforethe fact tables– Updating of dimensions drops allaggregations and therefore they need tobe recalculated– Full process of dimensions drops the data
  • 39. 39Processing Performance• Tabular is just a “collection of tables” sothere are no processing dependencies• Therefore it is much more flexible whenit comes to processing• You can partition the data within thetabular model so that you don‟t have toprocess the full data set each day butthe partitions cannot be processed inparallel
  • 40. 40Query Performance• Multidimensional query performance isdependent upon the partition designand the aggregation design• Tabular query performance does notneed to be tuned• Generally tabular will provide for betterquery performance especially if theusers are pulling large amounts of detaildata
  • 41. 41Security• Multidimensional bases security onmembers within a dimension• Tabular bases security on rows in atable• Both version support dynamic security• Multidimensional also allows for visualtotals and allowing users to usedrillthrough
  • 42. 42Microsoft Client Tools• Microsoft Excel can connect to both models.– Although the query performance benefitsof Tabular are lost when you query withMDX• PerformancePoint can only connect toTabular with the use of a custom data source• PowerView can only connect to Tabular• Most third party products can connect to bothmodels because Tabular is MDX compliant
  • 43. 43This slide deck is part of a recorded webinar.To view the FREE recording of this entirepresentation and download the slide deck, go tohttp://info.senturus.com/2013-05-16-Microsoft-SSAS.htmlThe Senturus library has over 90 other recordedwebinars, whitepapers, and demonstrations on assorted businessintelligence topics which may interest you.Go to the recorded resources
  • 44. 44Demonstration• How do these models look to the userin Excel?
  • 45. 45Summary Recommendations for Tabular• You should consider Tabular if:– You have a very short development timespan– Your data model is fairly simple– Your users are pulling large amounts ofdetail data and query performance isimportant– Cube has a lot of Distinct Counts– You want to use PowerView in SharePoint
  • 46. 46Things to Consider• Once you choose a path you cannotmigrate to the other version withoutstarting over• You will not be able to “merge” databetween Tabular and Multidimensionalcubes• Tabular can be risky if requirementschange mid-way through the project
  • 47. 47Further Resources: New Training CourseAdvanced Topics in Microsoft SSASJune 11 (7am-3pm PDT)• Learn how to– create global date calculations,– create named sets, which can help automate dashboardsand reports– use „many to many‟ relationships• $695• For more information and to register:http://www.senturus.com/Microsoft_SSAS.php
  • 48. 48This slide deck is part of a recorded webinar.To view the FREE recording of this entirepresentation and download the slide deck, go tohttp://info.senturus.com/2013-05-16-Microsoft-SSAS.htmlThe Senturus library has over 90 other recorded webinars,whitepapers, and demonstrations on assorted business intelligencetopics which may interest you.Go to the recorded resources
  • 49. 49Helping Companies Learn From the Past, Manage thePresent and Shape the Futurewww.senturus.com888-601-6010info@senturus.comCopyright 2013 by Senturus, Inc. This entire presentation iscopyrighted and may not be reused or distributed without the written consent ofSenturus, Inc.
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