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i need more exact details about MOLAP RRS feed

  • Question

  • hi

    can anyone answer me on this questions?

    1 why MOLAP  performs   with ten or fewer dimensions.?

    2 when i use MOLAP .where are the detail  and  aggregation  data  stored ?

    i mean this data is stored in cube or is cube and data warehouse

    3 why storage space to MOLAP is limited less tera byte?

    what is query language to MOLAP AND ROLAP ?

    thank you in advance

     

    Wednesday, January 12, 2011 1:02 PM

Answers

  • In addition to Vinu's & Santosh's post, MOLAP and ROLAP are storage modes for storing data. In the MOLAP storage mode the aggregations of the partition and a copy of its source data to be stored in a multidimensional structure in Analysis Services when the partition is processed. but In the ROLAP storage mode the aggregations of the partition to be stored in indexed views in the relational database that was specified in the partition's data source. Even ROLAP does not cause a copy of the source data to be stored in the Analysis Services data folders. 

    For more details, you can refer;


    Ani
    • Marked as answer by roarmoha Wednesday, January 12, 2011 2:14 PM
    Wednesday, January 12, 2011 1:54 PM

All replies

  • Hi,

    Please see my response to your questions -

    1 why MOLAP  performs   with ten or fewer dimensions.?
    SKJ:  It can work well even with for more dimensions.

    2 when i use MOLAP .where are the detail  and  aggregation  data  stored ?
    SKJ: In the Analysis Server i.e. Cubes

     

    3 why storage space to MOLAP is limited less tera byte?

    SKJ: I am not sure whether I got your question correctly or not. MOLAP stores all the granular level data and aggregations in the Analysis server in Microsoft proprietary format and thus consumes less space.

     

    4. What is query language to MOLAP AND ROLAP?

    SKJ: MDX

     

    HTH.

     

    Thanks,

    Santosh

     

    Wednesday, January 12, 2011 1:26 PM
  • 1. This is not correct. I can handle much more dimensions than you have specified

    http://technet.microsoft.com/en-us/library/ms365363.aspx

    2. Yes it is stored in cube. The Aggregations are stored in the cube partitions. It is physically stored in 

    .fact.data.hdr, .fact.data, .fact.string.data and few more files. Basically one measure group's data contains an Index, State, Aggregation, Aggregation Index, data and Metadata Partitions

    3. MDX is the query language. DMX is the query language for mining. I dont think there is any limit on the facts. However there is a limit of the size of dimension table (4 Gig limit). More details can be found here in this thread

    http://social.msdn.microsoft.com/Forums/en/sqlanalysisservices/thread/56f2d35c-8fbd-4801-89cb-8f17863d5156


    vinu
    Wednesday, January 12, 2011 1:33 PM
  • In addition to Vinu's & Santosh's post, MOLAP and ROLAP are storage modes for storing data. In the MOLAP storage mode the aggregations of the partition and a copy of its source data to be stored in a multidimensional structure in Analysis Services when the partition is processed. but In the ROLAP storage mode the aggregations of the partition to be stored in indexed views in the relational database that was specified in the partition's data source. Even ROLAP does not cause a copy of the source data to be stored in the Analysis Services data folders. 

    For more details, you can refer;


    Ani
    • Marked as answer by roarmoha Wednesday, January 12, 2011 2:14 PM
    Wednesday, January 12, 2011 1:54 PM
  • thanks to all
    Wednesday, January 12, 2011 2:17 PM