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Learn T-SQL Querying - Second Edition

You're reading from  Learn T-SQL Querying - Second Edition

Product type Book
Published in Feb 2024
Publisher Packt
ISBN-13 9781837638994
Pages 456 pages
Edition 2nd Edition
Languages
Authors (2):
Pedro Lopes Pedro Lopes
Profile icon Pedro Lopes
Pam Lahoud Pam Lahoud
Profile icon Pam Lahoud
View More author details

Table of Contents (18) Chapters

Preface 1. Part 1: Query Processing Fundamentals
2. Chapter 1: Understanding Query Processing 3. Chapter 2: Mechanics of the Query Optimizer 4. Part 2: Dos and Don’ts of T-SQL
5. Chapter 3: Exploring Query Execution Plans 6. Chapter 4: Indexing for T-SQL Performance 7. Chapter 5: Writing Elegant T-SQL Queries 8. Chapter 6: Discovering T-SQL Anti- Patterns in Depth 9. Part 3: Assembling Our Query Troubleshooting Toolbox
10. Chapter 7: Building Diagnostic Queries Using DMVs and DMFs 11. Chapter 8: Building XEvent Profiler Traces 12. Chapter 9: Comparative Analysis of Query Plans 13. Chapter 10: Tracking Performance History with Query Store 14. Chapter 11: Troubleshooting Live Queries 15. Chapter 12: Managing Optimizer Changes 16. Index 17. Other Books You May Enjoy

Avoiding unnecessary overhead with stored procedures

In stored procedures, use the SET NOCOUNT ON notation even when there’s a requirement to return the current row count during execution, as in the following example:

CREATE OR ALTER PROCEDURE [dbo].[uspStocksPerWorkOrder] @WorkOrderID [int]
AS
BEGIN
SET NOCOUNT ON;
     SELECT wo.StockedQty, wor.WorkOrderID
     FROM Production.WorkOrder AS wo
     LEFT JOIN Production.WorkOrderRouting AS wor
ON wo.WorkOrderID = wor.WorkOrderID
     WHERE wo.WorkOrderID = @WorkOrderID;
END;

When SET NOCOUNT is ON, the count indicating the number of rows affected by a T-SQL statement is not returned to the application layer, which provides a performance boost.

Note

The @@ROWCOUNT function will still be incremented even with SET NOCOUNT ON.

To put this to a test, we can use the ostress utility and simulate a client application executing...

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