YOU CAN TUNE YOUR OWN CODESQL Saturday #33 Charlotte

WHO IS MIKE?

10 years with SQL DBA roles of various sorts Blog: www.straightpathsql.com/ Syndicated at SQLServerPedia Full Time – Principal DBA at global insurance

company. “Spare” Time – Consult for SQL

Administration and Performance Issues President of new “Seacoast SQL” PASS

Chapter

Who Are You?

“Why is this so slow?!”

“It worked fine in dev!”

“The results came back fine… I’m done”

What Aren’t We Covering?

“Can’t you just make it

faster?!”

http://www.flickr.com/photos/irinaslutsky/4000761728/

www.flickr.com/photos/no3rdw/170950846/

www.flickr.com/photos/no3rdw/170950846/http://www.flickr.com/photos/dullhunk/359634390/

AGENDA

Tips For Slow Queries The Right Mindset & Some Best Practices Indexes & Statistics (Building Blocks) Query Plans (Not So Scary) SQL Profiler (Don’t tell my DBA friends..) Put it all together and CLAP DBAs don’t mean to be so mean*

*Maybe we do…, but let’s work it out

Goal 1

You will leave using the concepts we

discuss.

Goal 2

You won’t ever say, “done” until you know your code

PERFORMS

Goal 3

“Can’t we all just get

along??!”

Tips For Making Queries Slow

Right Mindset

RIGHT MINDSET

• SQL Is Declarative• Work With Sets• Watch Transaction Footprint• Join Where Necessary• Remember: Disk – Memory –

Query• Smaller Sets ASAP• Work with the columns you need

“Should I split this up?”

“Should I use -that- view?”

“How Many Reads Am I

doing?”

“What will happen in 1

year?”

“How many rows are

affected by that operation?”

HOW ARE YOU PROVING YOUR CODE?

• Working with representative volume?

• Testing various scenarios?• Before/After Testing?• Using Empirical Evidence?• Look and Feel with a Stop

Watch???

Indexes

What Are Indexes?

•Pointers To Data•B-Tree Structures•Sometimes – Hero Makers•Sometimes – Frustrations

Clustered Indexes

•Leaf Level Is The Data•Narrower Is Better•Ever-Increasing•Order By•Not Changing

Non-Clustered Indexes

•Leaf Level Has Index Data and Pointer Only•Joins•Common (and Selective) Search Criteria.

ScanSeek

“Bookmark/RID/KEY Lookups”Covering

What Does It All Mean?

Statistics

SARGable Queries

Search ARGuments

•Query That Can Use An Index

•(All Things Being Equal…)

•Generally: =, <, >, <=, =>,

BETWEEN, IN, LIKE (with exceptions).

•Some Rules but think of the

phonebook…

Fun(?) With Phonebooks

Some Tools

•IO Statistics

•Query Plans

•Profiler

Put It Together

Care

Look

Act

Prove It Out

http://www.flickr.com/photos/hikingartist/3515471358/

Goal 3

“Can’t we all just get

along??!”

Goal 1

You will leave using the concepts we

discuss.

Goal 2

You won’t ever say, “done” until you know your code

PERFORMS

You CAN Tune Your Own SQL Code

RESOURCES

mike@StraightPathSQL.comwww.SQLServerCentral.comwww.SQLServerPedia.comsqlblog.comblogs.msdn.com/craigfr/default.aspxhttp://sqlinthewild.co.za/ http://scarydba.wordpress.com/ http://www.straightpathsql.com/

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StraightPathSQL.com/ucandoit

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