Index columnstore SQL Server : guide pratique

C est le schema classique de type warehouse lorsque scans et aggregations dominent la charge.

CREATE TABLE dbo.FactSales
(
    SalesKey bigint NOT NULL,
    OrderDateKey int NOT NULL,
    CustomerKey int NOT NULL,
    ProductKey int NOT NULL,
    Quantity int NOT NULL,
    NetAmount decimal(18,2) NOT NULL
);

CREATE CLUSTERED COLUMNSTORE INDEX CCI_FactSales
ON dbo.FactSales;

Ce schema est utile quand l acces OLTP depend toujours du rowstore mais que le reporting profite d une projection analytique compressee.

CREATE TABLE dbo.SalesOrderDetail
(
    SalesOrderDetailID bigint NOT NULL PRIMARY KEY,
    SalesOrderID bigint NOT NULL,
    ProductID int NOT NULL,
    OrderQty int NOT NULL,
    UnitPrice money NOT NULL,
    ModifiedDate datetime2 NOT NULL
);

CREATE NONCLUSTERED COLUMNSTORE INDEX NCCI_SalesOrderDetail_Analytics
ON dbo.SalesOrderDetail (SalesOrderID, ProductID, OrderQty, UnitPrice, ModifiedDate);

Le succes de columnstore depend de la qualite des rowgroups, pas seulement de l existence de l index.

SELECT
    OBJECT_NAME(object_id) AS table_name,
    row_group_id,
    state_desc,
    total_rows,
    deleted_rows,
    size_in_bytes / 1024.0 / 1024.0 AS size_mb
FROM sys.dm_db_column_store_row_group_physical_stats
WHERE object_id = OBJECT_ID('dbo.FactSales')
ORDER BY row_group_id;