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Question 243 - DP-203 discussion

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You have an Azure Synapse Analytics dedicated SQL pool.

You need to create a table named FactInternetSales that will be a large fact table in a dimensional model. FactInternetSales will contain 100 million rows and two columns named SalesAmount and OrderQuantity. Queries executed on FactInternetSales will aggregate the values in SalesAmount and OrderQuantity from the last year for a specific product. The solution must minimize the data size and query execution time. How should you complete the code? To answer, select the appropriate options in the answer area. NOTE: Each correct selection is worth one point.

Question 243
Correct answer: Question 243

Explanation:

Box 1: (CLUSTERED COLUMNSTORE INDEX

CLUSTERED COLUMNSTORE INDEX

Columnstore indexes are the standard for storing and querying large data warehousing fact tables. This index uses column-based data storage and query processing to achieve gains up to 10 times the query performance in your data warehouse over traditional row-oriented storage. You can also achieve gains up to 10 times the data compression over the uncompressed data size. Beginning with SQL Server 2016 (13.x) SP1, columnstore indexes enable operational analytics: the ability to run performant real-time analytics on a transactional workload.

Note: Clustered columnstore index

A clustered columnstore index is the physical storage for the entire table.

To reduce fragmentation of the column segments and improve performance, the columnstore index might store some data temporarily into a clustered index called a deltastore and a B-tree list of IDs for deleted rows. The deltastore operations are handled behind the scenes. To return the correct query results, the clustered columnstore index combines query results from both the columnstore and the deltastore.

Box 2: HASH([ProductKey])

A hash distributed table distributes rows based on the value in the distribution column. A hash distributed table is designed to achieve high performance for queries on large tables. Choose a distribution column with data that distributes evenly

Reference:

https://docs.microsoft.com/en-us/sql/relational-databases/indexes/columnstore-indexes-overview

https://docs.microsoft.com/en-us/azure/synapse-analytics/sql-data-warehouse/sql-data-warehousetables-overview https://docs.microsoft.com/en-us/azure/synapse-analytics/sql-data-warehouse/sql-data-warehousetables-distribute

asked 02/10/2024
Martin White
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