Column-Store index in SQL Server

Column-Store Indexes
Column-Store index is designed for improving query performance which is used for a heavy amount of data like data warehouse fact tables. This type of index stores the index data in column-based rather than row-based. This index is introduced in version SQL server 2012; basically this is a column-based non-clustered index.

Why should we use Column-Store Index
Column-Store index provides a very high level of compression, typically by 10 times, to significantly reduce your data warehouse storage cost. For analytics, a column-store index offers an order of magnitude better performance than a B-Tree index.
Columns store values from the same domain and commonly have similar values, which result in high compression rates. I/O bottlenecks in your system are minimized or eliminated, and memory footprint is reduced significantly.
High compression rates improve query performance by using a smaller in-memory footprint. In turn, query performance can improve because SQL Server can perform more query and data operations in memory.
Batch execution improves query performance, typically by two to four times, by processing multiple rows together.
Queries often select only a few columns from a table, which reduces total I/O from the physical media.

1-    Use a clustered column-store index to store fact tables and large dimension tables for data warehousing workloads. This method improves query performance and data compression by up to 10 times.
2-    Use a non-clustered column-store index to perform analysis in real-time on an OLTP workload.

How to create a column-store index
Using the following script you can create the column-store index in SQL Server.

--to create a column-store index
CREATE COLUMNSTORE INDEX IX_OrderDetail_ProductIDOrderQty_ColumnStore
ON Sales.OrderDetail (ProductId,OrderQty);

Source of content from Microsoft: column-store index

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