sql server optimization checklist

Grant Fritchey | www.ScaryDBA.com

www.ScaryDBA.com

SQL Server Optimization

Checklist

Grant FritcheyProduct EvangelistRed Gate Software


Agenda

Server Configuration

SQL Server Administration

Database Design

TSQL Coding

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Get it Touch

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scarydba.com

[email protected]

@gfritchey


Test

Test

Test

Test

Test

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Remember

This is focused on performance tuning

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Remember


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There are always exceptions


Remember



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Your hardware may be DIFFERENT


Remember



Your hardware may be different

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Did I mention test?


Remember




Did I mention test?

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Incre

mental changes


Remember




Did I mention test?

Incremental changes

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onitor your servers


Remember




Did I mention test?

Incremental changes

Monitor your servers

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I am NOT a systems expert


Remember




Did I mention test?

Incremental changes


I am not a systems expert

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You might want to TEST


Remember




Did I mention test?

Incremental changes


I am not a systems expert

You might want to test

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Server Configuration

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Memory CPU Disks


SQL Server Configuration:

Memory

>4g enable AWE

» On 2008R2 or less

» On 32-bit systems

Dynamic

» but set a minimum and a maximum value

Optimize for Ad Hoc Workloads

» Enable on all servers

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CPU

Cost Threshold for parallelism

» 5, the default, is too low

» OLTP = 40

» Reporting = 25

Max Degree of Parallelism

» Leave it on, after you change the cost threshold

Consider using Query Governor

» Set a cost limit

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Storage

TEMPDB» Separate from other data when possible» Multiple Files

— Not equal to #of processors— Equal sized files

Compression» Minimum, index compression

More disks is better» But only if you have more controllers

Spend money» Buy faster disks

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SQL Server

Administration

Maintain Statistics» Enable AUTO_CREATE & AUTO_UPDATE » You must also plan for manual updates» You may need FULL SCAN» Consider ASYNC

Defragment your indexes» Number of pages does matter» You can defrag below 1000 pages» You can’t defrag below 8 pages» Separate defrag & statistics updates

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SQL Server

Administration 2

Avoid dangerous settings» Disable AUTO_CLOSE» Disable AUTO_SHRINK

Do not use the Profiler GUI on production systems» Create a server-side trace using TSQL scripts

(prior to 2008)» Use extended events

— Consider for 2008 or better— Absolutely for 2012 or better

Set Blocked Process Threshold» Based on your system

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Database Design

Storage

Constraints

Indexes

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Database Design: Storage

Separate Log & Data

Multiple File Groups

» Even on a single drive

Turn off auto-grow

» If not possible, used fixed growth, not percentage

Consider In-Memory

» 2014 only

» I/O Latch waits

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Database Design:

Constraints

Normalize your Data

» Normalization benefits performance

Enforce Constraints

» Foreign keys

» Primary keys

» Unique values

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Database Design: Indexes -

General

Narrow

» As narrow as possible

Integers

» Believe it or not, they’re better

Choose leading edge carefully

» Most selective column

Covering Indexes are fastest

» Use INCLUDE

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Database Design: Indexes -

Clustered

Again, Narrow

» As narrow as possible

Design around the clustered index

» Most frequent used path to data

Rebuilding clustered index

» Use DROP_EXISTING

Avoid columns that get updated frequently

» This means all non-clustered indexes are updated too

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TSQL Coding

Return only the data you need, when you need it

Use stored procedures or parameterized queries

» Encourages plan reuse

» Prevents SQL Injection

Avoid cursors, WHILE, LOOP

» Row By Agonizing Row style processing

Qualify all object names

» Reduces lookup costs

Avoid using ‘sp_*’ for procedure names

» Eliminates additional read to the master database

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TSQL Coding 2

Avoid nonsargeable conditions

» Meaning functions on columns

» Or, using LIKE ‘%Anything’

Use SET NOCOUNT ON

» Reduces returns on network

Do not nest views

» Or join them. It confuses the optimizer

Don’t use optimizer hints

» More often than not it causes problems

» Especially NOLOCK

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TSQL Coding 3

Avoid Recompiling Execution Plans

» Stored procedures & parameterized queries

» Table variables instead of temp tables

» ANSI standards on connection settings— And Don’t change them within a query

» Don’t interleave DDL & DML

Adopt best practices for transactions

» Keep scope as short as possible

» Use SET XACT_ABORT

» Consider using READ COMMITTED SNAPSHOT

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Relax

It’s not that bad

Most things can be changed

Help is available

Test everything

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Questions?

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