Download Performance Audit

Managing SQL Server
Performance
AtlantaMDF
August 11, 2003
By Larry Ansley
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Performance Maximization Plan
In Only 4 Easy Steps
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Denormalize
Index Everything
Use Full-Text Searches Liberally
Get a Bigger, More Powerful System
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Performance Areas
Hardware
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Memory
CPU
Storage
Network
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Performance Areas
Operating System
• Configuration
• Version Upgrades
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Performance Areas
Operating System
• Configuration
• File Management
• Version Upgrades
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Performance Areas
SQL Server
• Configuration & Options
• File Management
• Version Upgrades
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Performance Areas
Databases
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Configuration & Options
Tables
Indexes
File Management
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Performance Areas
Stored Procedures
• Logic
• Best Practices
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Performance Killers
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Poor indexing
Inaccurate statistics
Excessive fragmentation
Non-reusable execution plans
Frequent recompilation
Excessive blocking and deadlocks
Poor query design
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Performance Killers
8. Poor database design
9. Improper cursor use
10. Ineffective connection pooling
11. Improper database log configuration
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Taming The Performance Killers
• Planning
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ER Diagrams
Data Modeling
Capacity Requirements
Procedure Case Analysis
• Follow Best Practices in Development
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Taming The Performance Killers
• Good Record Keeping
– Logs
– Baselines
– Audits
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Performance Baselines
Benefits
• Allows us to analyze resource bottlenecks
• Allows us to troubleshoot by comparing
system utilization patterns with preestablished baselines
• Allows us to make accurate estimates in
capacity planning and scheduling hardware
upgrades
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Performance Baselines
Benefits
• Aids us in identifying low utilization
periods, when we can execute
administrative activities
• Helps us distinguish between performance
perception and reality
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Performance Baselines
Baseline Tools
• System Monitor (Key Resource Counters)
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CPU – % Processor Time (85%)
CPU – Processor Queue Length (2)
Memory – Available Bytes (4 MB)
Memory – Pages / Sec (20)
Memory – Buffer Cache Hit Ratio ( 90%)
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Performance Baselines
Baseline Tools
• System Monitor (Key Resource Counters)
– Disk – % Disk Time (90%)
– Disk – Avg. Disk Queue Length (number of
spindles + 2)
– Network – % Net Utilization (30% for
Ethernet)
– SQL Server – User Connections
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Performance Baselines
Baseline Tools
• SQL Profiler
– Record Traces for Major Processes
– Duration, CPU, Reads, Writes
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Performance Audit
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System Monitor
Hardware
Operating System
SQL Server Configuration
Database Settings
Indexes
Application and Transact-SQL
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Performance Audit
System Monitor
• Processor: % Processor Time
– Recurring period exceeding 80% indicate CPU
bottlenecks
• System: Processor Queue Length
– Recurring periods exceeding 2 per CPU
indicate CPU bottlenecks
– Consider Maximum Worker Threads setting
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Performance Audit
System Monitor
• Memory: Pages / Sec
– Average around 0 over 24 hours
– Average over 20 indicates memory bottleneck
• Memory: Available Bytes
– Should be greater than 5 MB
– Dedicated SQL Servers attempt to maintain 410 MB free
– Less than 5 MB indicates a memory bottleneck
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Performance Audit
System Monitor
• SQL Server Buffer: Buffer Cache Hit Ratio
– For OLTP application, should exceed 90%,
ideally around 99%
– OLAP (Analysis Services) application work
well with lower ratios
• SQL Server General: User Connections
– If this exceeds 255, Maximum Worker Threads
setting should be increased to remain greater
than user connections, thus avoiding thread
sharing.
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Performance Audit
System Monitor
• Physical Disk: % Disk Time
– Should run less than 55%
– Recurring periods (10 minutes or more)
exceeding 55% indicate I/O bottlenecks
• Physical Disk: Avg. Disk Queue Length
– Should run less than 2 per spindle
– Recurring periods exceeding 2 indicate I/O
bottlenecks
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Performance Audit
Hardware
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Number of CPUs
CPU MHz
CPU L2 Cache Size
Physical Ram Amount
Total Amount of Available Drive Space on
Server
• Total Number of Physical Drives in Each
Array
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Performance Audit
Hardware
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Hardware vs. Software Raid
RAID Level of Each Array Used
Disk Fragmentation Level
Location of Operating System
Location of SQL Server Executables
Location of Swap File
Location of tempdb Database
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Performance Audit
Hardware
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Location of System Databases
Location of User Databases
Location of Log Files
Number of Disk Controllers in Server
Type of Disk Controllers in Server
Size of Cache in Disk Controllers In Server
Is Write Cache in Disk Controller On or Off
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Performance Audit
Hardware
• Speed of Disk Drives
• How Many Network Cards Are in Server
• Are the Network Cards Hard-Coded for
Speed/Duplex
• Are the Network Cards Attached to a
Switch
• Are All the Hardware Drivers Up-to-Date
• Is This Physical Server Dedicated to SQL
Server
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Performance Audit
Operating System
• Are the Disk Partitions NTFS 5.0
• Is “NTFS Data File Encryption and
Compression” Turned Off
• Is the Server Updated With the Latest
Service Pack
• Does the Server Have the Most Current,
Microsoft-Certified Hardware Drivers
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Performance Audit
Operating System
• Is the Windows 2000 Server Configured as
a Stand-Alone Server
• Are the Physical Files on the Server Overly
Fragmented
• Is the “Application Response” Setting Set to
“Optimize Performance” for “Background
Services”
• Has Security Auditing Been Turned On
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Performance Audit
Operating System
• How Large Is the Server’s PAGEFILE.SYS
swap file
• Have Unnecessary Services Been Turned
Off
• Have All Unnecessary Network Protocols
Been Turned Off
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Performance Audit
SQL Server Configuration
Settings
Advanced Restart Default Current
Affinity mask
Yes
Yes
0
Awe enabled
Yes
Yes
0
Cost threshold
for parallelism
Yes
No
5
Cursor
threshold
Yes
No
-1
Fill factor (%)
Yes
Yes
0
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Performance Audit
SQL Server Configuration
Settings
Index create
memory (KB)
Lightweight
pooling
Locks
Max degree of
parallelism
Advanced Restart Default Current
Yes
No
0
Yes
Yes
0
Yes
Yes
Yes
No
0
0
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Performance Audit
SQL Server Configuration
Settings
Max server
memory (MB)
Max text repl
size (B)
Max worker
threads
Min memory
per query (KB)
Advanced Restart Default Current
Yes
No
No
No
2,147,4
83,647
65536
Yes
Yes
255
Yes
No
1024
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Performance Audit
SQL Server Configuration
Settings
Advanced Restart Default Current
Min server
memory (MB)
Nested triggers
Yes
No
0
No
No
1
Network packet
size (B)
Open objects
Yes
No
4096
Yes
Yes
0
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Performance Audit
SQL Server Configuration
Settings
Advanced Restart Default Current
Priority boost
Yes
Yes
0
Query governor
cost limit
Query wait (s)
Recovery
interval (min)
Yes
No
0
Yes
Yes
No
No
-1
0
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Performance Audit
SQL Server Configuration
Settings
Scan for startup
procs
Set working set
size
User
connections
Advanced Restart Default Current
Yes
No
0
Yes
Yes
0
Yes
No
0
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Performance Audit
Database Configuration Settings
Database Setting
Auto_close
Auto_create_statistics
Auto_update_statistics
Auto_shrink
Read_only
Torn_page_detection
Default
Off
On
On
Off
Off
On in 2000
Off in 7.0
Current
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Performance Audit
Database Configuration Settings
Database Setting
Compatibility level
Database auto grow
Transaction log auto
grow
Default
80 for 2000
70 for 7.0
On
On
Current
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Performance Audit
Indexes
• Have you run the Index Tuning Wizard
recently
• Does every table in each database have a
clustered index
• Are any of the columns in any table indexed
more than once
• Are there any indexes that are not being
used in queries
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Performance Audit
Indexes
• Are the indexes too wide
• Do the tables that are joined have the
appropriate indexes on the joined columns
• Are the indexes unique enough to be useful
• Are you taking advantage of covering
indexes
• How often are indexes rebuilt
• What is your index fillfactor
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Performance Audit
Transact-SQL
• Does the Transaction-SQL code return more
data than needed
• Are cursors being used when they don’t
need to be
• Are Union and Union Select properly used
• Is Select Distinct being used properly
• Is the Where clause Sargable
• Are temp tables used when they aren’t
needed
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Performance Audit
Transact-SQL
• Are hints being properly used in queries
• Are view unnecessarily being used
• Are stored procedures being used whenever
possible
• Inside stored procedures, is Set NoCount
On being used
• Do any of your stored procedures start with
sp_
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Performance Audit
Transact-SQL
• Are all stored procedures owned by DBO
and referred to in the form of
databaseowner.objectname
• Are you using constraints or triggers for
referential integrity
• Are transactions being kept as short as
possible
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Performance Audit
Applications
• Is the application using stored procedures,
strings of T-SQL code, or using an object
model, like ADO, to communicate with
SQL Server
• What method is the application using to
communicate with SQL Server: DB-Lib,
DAO, RDO, ADO, .Net
• Is the application using ODBC or OLE DB
to communicate with SQL Server
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Performance Audit
Applications
• Is the application taking advantage of
connection pooling
• Is the application properly opening, reusing,
and closing connections
• Is the T-SQL code being sent to SQL Server
optimized for SQL Server, or is it generic
SQL
• Does the application return unnecessary
data
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Performance Audit
Applications
• Is the application taking advantage of
connection pooling
• Is the application properly opening, reusing,
and closing connections
• Is the T-SQL code being sent to SQL Server
optimized for SQL Server, or is it generic
SQL
• Does the application return unnecessary
data
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Performance Audit
Applications
• Does the application keep transaction open
when the user is modifying data
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Monitoring & Measuring Tools
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Enterprise Manager
Query Analyzer
System Monitor
SQL Profiler
3rd Party
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Monitoring & Measuring Tools
Enterprise Manager
• Management / Current Activity
– Process Info (sp_who2)
– Locks / Process ID (sp_lock)
– Locks / Object (sp_lock)
• Management / SQL Server Logs
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Monitoring & Measuring Tools
Query Analyzer
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sp_who / sp_who2
sp_lock
sp_spaceused
sp_monitor
Showplan_Text
Showplan_All
Set Statistics IO
Set Statistics Time
Set Statistics Profile
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Monitoring & Measuring Tools
Query Analyzer
• DBCC Commands
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DBCC UserOptions
DBCC Show_Statistics
DBCC ShowContig
DBCC IndexDefrag
DBCC PerfMon
DBCC TraceOn / DBCC TraceOff
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Monitoring & Measuring Tools
Query Analyzer
• Built-in Functions
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@@CPU_Busy
@@IO_Busy
@@Packet_Errors
@@Connections
@@Total_Read
@@Total_Write
@@Total_Errors
@@TranCount
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Monitoring & Measuring Tools
Query Analyzer
• System Tables
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Master.dbo.sysprocesses
Master.dbo.syslockinfo
Master.dbo.sysperfinfo
Master.dbo.syscacheobjects
dbo.sysobjects
dbo.sysindexes
• _WA_Sys_AcctNo_2216C367, hind_1400444113_1A_6A_7A
– dbo.sysindexkeys
– dbo.syscolumns
– dbo.sysdepends
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SQL Profiler & Query Analyzer
Highest Execution Count
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SQL Profiler & Query Analyzer
Longest Single Duration
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SQL Profiler & Query Analyzer
Longest Aggregate Duration
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SQL Profiler & Query Analyzer
Recompiles
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Suggested Reading
Printed Books
• Inside SQL Server 2000
– Kalen Delaney (Microsoft Press, 2001)
• SQL Server Query Performance Tuning
Distilled
– Sajal Dam (Curlingstone, 2003)
• SQL Server 2000 for Experienced DBAs
– Brian Knight (Osborne, 2003)
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Suggested Reading
E-Books
• Microsoft SQL Server Books On Line
• Start to Finish Guide to SQL Server
Performance Monitoring
– Brian Kelly (NetImpress, 2002)
• Hands-On SQL Server 2000
Troubleshooting: Locking and Blocking
– Kalen Delaney (NetImpress, 2003)
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Suggested Reading
Periodicals
• SQL Server Magazine (Penton Media)
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Suggested Reading
Web Sites & Web Articles
• http://www.sql-server-performance.com
– Brad McGehee – How to Perform a SQL Server
Performance Audit; and many others
– Randy Dyess – An Introduction to SQL Server
Query Tuning; and many others
– Joe Chang – SQL Server Quantitative
Performance Analysis
• http://www.sqlservercentral.com
– Brian Knight
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Suggested Reading
Web Sites & Web Articles
• http://www.sqlmag.com
– Kalen Delaney – Recompiling Riddles; and
many more
– Neil Pike – What is the precedence of the SET
commands, database options, session options,
etc.
• http://www.sqlteam.com
• http://www.algonet.se/~sommar/index.html
– Erland Sommarskog MBP – aba_lockinfo
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Suggested Reading
Web Sites & Web Articles
• http://www.msdn.microsoft.com
• http://support.microsoft.com/default.aspx?s
cid=fh;EN-US;KBHOWTO
• http://www.msdn.microsoft.com/library/def
ault.asp?url=/nhp/Default.asp?contentid=28
000409
• http://www.microsoft.com/sql/
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