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Message Posted: Thu, 14 Jun 2012 @ 22:41:43 GMT


     
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Subj:   Index Best Practices for Dimension Model Data?
 
From:   Nathan_S_Smith

Hi,

Looking at a dimensional model where there exists a billion row fact table and some million row dimension tables, what would be the best practice for creating primary indexes and or secondary indexes on the tables to provide efficient query execution?

An example might look like the following:

     REGION_DIM TABLE
     Region_ID unique
     Country
     City
     State
     Region_Description
     Region_Code

     100 rows

     PRODUCT_DIM TABLE
     Product_Dim_ID unique
     Product_Group
     Product_Family
     Product_Brand

     5 million rows

     CUSTOMER_DIM TABLE
     Customer_Dim_ID unique
     Customer_Name
     Customer_State
     Customer_City

     10 million rows

     ORGANIZATION_DIM TABLE
     Org_Dim_ID unique
     Org_Name
     Org_Region_ID
     Org_Division
     Org_Group
     Org_Office

     5 K rows

     CALENDAR_DIM TABLE
     Cal_Date unique
     Cal_Week
     Cal_Month
     Cal_Quarter
     Cal_Year

     7,300 rows

RESULTS_FACT TABLE

Each dimension provides a value to form the PK of the fact table.

Additive quantity fact attributes can be summarized from day up to quarter.

Would like ad-hoc capability such that not all dimension values are used.

Example: Show all products, customers, organization for a specific region over date.

Show specific customer for all products.

Show Customers supported by a specific organization.

Would the PI be all the dimension ids for distribution?? A specific combination of ids for the most common queries?

Partitioning by Date or Date part of the PI?

Several secondary indexes on various dimension ids?

Trial and error query explain plan evaluation?


Question too complex for email?

Is there a TD manual reference for this type of information?


Thanks,

Nathan



     
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