sql-server-samples/samples/features/intelligent-query-processing/IQP Demo - Batch Mode MGF.sql

-- ******************************************************** --
-- Batch mode Memory Grant Feedback

-- See https://aka.ms/IQP for more background

-- Demo scripts: https://aka.ms/IQPDemos 

-- This demo is on SQL Server 2017 and Azure SQL DB

-- Email IntelligentQP@microsoft.com for questions\feedback
-- ******************************************************** --

USE [master];
GO

ALTER DATABASE [WideWorldImportersDW] SET COMPATIBILITY_LEVEL = 140;
GO

USE [WideWorldImportersDW];
GO

-- Intentionally forcing a row underestimate
CREATE OR ALTER PROCEDURE [FactOrderByLineageKey]
	@LineageKey INT 
AS
SELECT [fo].[Order Key], [fo].[Description] 
FROM [Fact].[Order] AS [fo]
INNER HASH JOIN [Dimension].[Stock Item] AS [si] 
	ON [fo].[Stock Item Key] = [si].[Stock Item Key]
WHERE [fo].[Lineage Key] = @LineageKey
	AND [si].[Lead Time Days] > 0
ORDER BY [fo].[Stock Item Key], [fo].[Order Date Key] DESC
OPTION (MAXDOP 1);
GO

-- Compiled and executed using a lineage key that doesn't have rows
EXEC [FactOrderByLineageKey] 8;
GO

-- Execute this query a few times - each time looking at 
-- the plan to see impact on spills, memory grant size, and run time
EXEC [FactOrderByLineageKey] 9;
GO