High Performance SQL Server: the Go Faster Book

213 Pages·2016·7.605 MB·English

by  Nevarez, Benjamin

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THE EXPERT’S VOICE® IN SQL
High Performance
SQL Server
The Go Faster Book
—
Bringing consistent response
time to mission-critical applications
—
Benjamin Nevarez
High Performance
SQL Server
The Go Faster Book

Benjamin Nevarez
High Performance SQL Server: The Go Faster Book
Benjamin Nevarez
Santa Clarita, California, USA
ISBN-13 (pbk): 978-1-4842-2270-6 ISBN-13 (electronic): 978-1-4842-2271-3
DOI 10.1007/978-1-4842-2271-3
Library of Congress Control Number: 2016959790
Copyright © 2016 by Benjamin Nevarez
This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is
concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction
on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic
adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed.
Trademarked names, logos, and images may appear in this book. Rather than use a trademark symbol with every
occurrence of a trademarked name, logo, or image we use the names, logos, and images only in an editorial fashion
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The use in this publication of trade names, trademarks, service marks, and similar terms, even if they are not identified
as such, is not to be taken as an expression of opinion as to whether or not they are subject to proprietary rights.
While the advice and information in this book are believed to be true and accurate at the date of publication, neither
the authors nor the editors nor the publisher can accept any legal responsibility for any errors or omissions that may
be made. The publisher makes no warranty, express or implied, with respect to the material contained herein.
Managing Director: Welmoed Spahr
Lead Editor: Jonathan Gennick
Development Editor: Laura Berendson
Technical Reviewer: Richard Douglas, Mike Walsh, George Anderson
Editorial Board: Steve Anglin, Pramila Balan, Laura Berendson, Aaron Black, Louise Corrigan,
Jonathan Gennick, Todd Green, Robert Hutchinson, Celestin Suresh John, Nikhil Karkal,
James Markham, Susan McDermott, Matthew Moodie, Natalie Pao, Gwenan Spearing
Coordinating Editor: Jill Balzano
Copy Editor: Ann Dickson
Compositor: SPi Global
Indexer: Spi Global
Artist: SPi Global
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Printed on acid-free paper
Th is book is dedicated to my sons, Diego, Benjamin, and David
Contents at a Glance
About the Author .....................................................................................................xv
About the Technical Reviewers .............................................................................xvii
Acknowledgments ..................................................................................................xix
Introduction ............................................................................................................xxi
■ Chapter 1: How SQL Server Works ........................................................................1
■ Chapter 2: Analyzing Wait Statistics ...................................................................21
■ Chapter 3: The Query Store ..................................................................................45
■ Chapter 4: SQL Server Confi guration ...................................................................71
■ Chapter 5: tempdb Troubleshooting and Confi guration .......................................85
■ Chapter 6: SQL Server In-Memory Technologies ...............................................101
■ Chapter 7: Performance Troubleshooting ..........................................................131
■ Chapter 8: Indexing ...........................................................................................155
■ Chapter 9: SQL Server Storage ..........................................................................181
Index .....................................................................................................................197
v
Contents
About the Author .....................................................................................................xv
About the Technical Reviewers .............................................................................xvii
Acknowledgments ..................................................................................................xix
Introduction ............................................................................................................xxi
■ Chapter 1: How SQL Server Works ........................................................................1
TDS/Network Protocols ....................................................................................................1
How Work Is Performed ....................................................................................................3
SQLOS .....................................................................................................................................................3
Schedulers ..............................................................................................................................................3
Workers ..................................................................................................................................................5
Query Optimization ...........................................................................................................8
Parsing and Binding ...............................................................................................................................8
Query Optimization .................................................................................................................................9
Plan Caching .........................................................................................................................................12
Query Execution .............................................................................................................13
Operators ..............................................................................................................................................13
Data Access Operators .........................................................................................................................14
Aggregations ........................................................................................................................................15
Joins .....................................................................................................................................................15
Parallelism ............................................................................................................................................16
Updates.................................................................................................................................................16
vii
■ CONTENTS
Memory Grants ...............................................................................................................17
Locks and Latches..........................................................................................................18
Summary ........................................................................................................................19
■ Chapter 2: Analyzing Wait Statistics ...................................................................21
Introduction ....................................................................................................................22
Waits Information ...........................................................................................................26
sys.dm_os_wait_stats ..........................................................................................................................26
sys.dm_exec_session_wait_stats ........................................................................................................30
Extended Events ...................................................................................................................................30
system_health Extended Event Session ...............................................................................................32
Example: Analyzing CXPACKET Waits ............................................................................34
Latches and Spinlocks ...................................................................................................37
Waits ..............................................................................................................................39
CX_PACKET ...........................................................................................................................................39
PAGELATCH_ and PAGEIOLATCH_ .........................................................................................................39
ASYNC_NETWORK_IO ...........................................................................................................................39
SOS_SCHEDULER_YIELD ......................................................................................................................39
THREADPOOL ........................................................................................................................................39
PREEMPTIVE_* ......................................................................................................................................40
OLEDB ...................................................................................................................................................40
IO_COMPLETION ...................................................................................................................................40
WRITELOG .............................................................................................................................................40
Timer Wait Types ...................................................................................................................................40
Blocking .........................................................................................................................42
In-Memory OLTP .............................................................................................................43
Summary ........................................................................................................................43
viii
■ CONTENTS
■ Chapter 3: The Query Store ..................................................................................45
Why Is a Query Slow? .....................................................................................................45
Plan Changes .................................................................................................................45
How the Query Store Can Help .......................................................................................47
Plan Regressions .................................................................................................................................47
SQL Server Upgrades ...........................................................................................................................47
Application/Hardware Changes ............................................................................................................47
Identify Expensive Queries ..................................................................................................................47
Identify Ad Hoc Workloads ....................................................................................................................48
Architecture ....................................................................................................................48
Enabling, Purging, and Disabling the Query Store ..........................................................50
Using the Query Store ....................................................................................................55
Performance Troubleshooting ........................................................................................59
Incomplete Queries ........................................................................................................61
Force Failure ..................................................................................................................64
Catalog Views .................................................................................................................65
Live Query Statistics.......................................................................................................67
Summary ........................................................................................................................69
■ Chapter 4: SQL Server Confi guration ...................................................................71
Statistics Update ............................................................................................................71
Standard Automatic Statistics Update ..................................................................................................73
Trace Flag 2371 and SQL Server 2016 .................................................................................................73
tempdb Confi guration .....................................................................................................73
Query Optimizer Hotfi xes and Trace Flag 4199 ..............................................................74
Max Degree of Parallelism .............................................................................................75
Cost Threshold for Parallelism .......................................................................................77
ix
■ CONTENTS
Instant File Initialization .................................................................................................77
Cardinality Estimator ......................................................................................................78
Optimize for Ad Hoc Workloads ......................................................................................79
SQL Server Editions ........................................................................................................80
Memory Confi guration ....................................................................................................80
Lock Pages in Memory ...................................................................................................81
Backup Compression Default .........................................................................................82
Query Governor Cost Limit .............................................................................................82
Blocked Process Threshold ............................................................................................82
Advanced Trace Flags .....................................................................................................83
Summary ........................................................................................................................84
■ Chapter 5: tempdb Troubleshooting and Confi guration .......................................85
DML Contention ..............................................................................................................85
Describing tempdb Latch Contention ...................................................................................................88
Fixing tempdb Latch Contention ...........................................................................................................89
Using Multiple Data Files ................................................................................................89
Trace Flags 1117 and 1118 ............................................................................................89
What Is New in SQL Server 2016 ...................................................................................90
tempdb Events ...............................................................................................................92
DDL Contention ...............................................................................................................97
tempdb Spill Warnings ...................................................................................................97
Sort Warning .........................................................................................................................................97
Hash Warning .......................................................................................................................................98
Exchange Warning ................................................................................................................................98
Monitoring Disk Space ...................................................................................................98
Summary ........................................................................................................................99
x
■ CONTENTS
■ Chapter 6: SQL Server In-Memory Technologies ...............................................101
In-Memory OLTP ...........................................................................................................102
What Is New in SQL Server 2016 ........................................................................................................103
Memory-Optimized Tables ..................................................................................................................103
Indexes ...............................................................................................................................................106
Natively Compiled Modules ................................................................................................................108
Changing Tables and Natively Compiled Modules ..............................................................................110
Native Compilation .............................................................................................................................112
Memory-Optimized Table Variables ....................................................................................................113
Current Limitations .............................................................................................................................114
Columnstore Indexes ....................................................................................................114
Examples ............................................................................................................................................116
Operational Analytics ....................................................................................................121
Using Disk-Based Tables ....................................................................................................................123
Using Memory-Optimized Tables ........................................................................................................126
Summary ......................................................................................................................129
■ Chapter 7: Performance Troubleshooting ..........................................................131
Performance Counters .................................................................................................132
Comparing Batches and Transactions ................................................................................................133
Log Growths........................................................................................................................................135
Data File(s) Size (KB) ..........................................................................................................................137
Page Reads/Sec ..................................................................................................................................137
Page Writes/Sec .................................................................................................................................137
Page Life Expectancy..........................................................................................................................137
Buffer Cache Hit Ratio ........................................................................................................................138
% Processor Time ...............................................................................................................................138
Processor Queue Length ....................................................................................................................139
Latches ...............................................................................................................................................140
Locks ..................................................................................................................................................140
LogicalDisk and PhysicalDisk .............................................................................................................140
xi