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1. Anil Desai
http://AnilDesai.net
Austin CodeCamp 2010

2.  Anil Desai
◦ Independent consultant (Austin, TX)
◦ Author of numerous IT books
◦ Instructor, “Implementing and Managing SQL Server 2005”
(Keystone Learning)
◦ Info: http://AnilDesai.net or Anil@AnilDesai.net

3. I. Performance Monitoring Overview
II. Monitoring Database Servers
III. Using SQL Profiler
IV. Using the Database Engine Tuning Advisor
V. Application Design Tips
VI. Managing Processes, Locking, and Deadlocks

4. Developing processes and approaches for
performance optimization

5.  Best Practices:
◦ Optimize for
real-world
workloads
◦ Monitor/review
performance
regularly
◦ Focus on specific
issues
Establish a
baseline
Identify
bottlenecks
Make one
change at a time
Measure
performance
Repeat
(if desired)

6. System/OS
Windows Performance
Monitor
Alerts (Performance-
Based)
SQL Server
Activity Monitor
SQL Profiler / SQL Trace
Database Engine
Tuning Advisor
Dynamic Management
Views (DMVs)
Query-
Level
Database Engine
Tuning Advisor
Query Execution Plans

7. Server-Level
Issues
• Users are reporting database timeouts
• Intermittent transaction timeouts
• “The server/application seem sluggish”
Application-
Specific
Issues
• “Application A is running more slowly
than usual”
• “The End-of-Month report is taking too
long to run.”
Other Issues
• Ad-hoc reports are running slowly
• CPU, memory, disk, or network alerts
are being generated

8. Using SQL Server tools and features
to monitor database activity

9.  Available in all current versions of Windows
 Statistics are organized into:
◦ Objects
◦ Counters
◦ Instances
 Data Collector Sets
◦ Windows Vista / Windows 7 / Windows Server 2008
◦ Used to report on performance data that is collected over
time
◦ Includes built-in System Diagnostics and System Performance
collectors and reports

10.  Backup Device
◦ Device throughput Bytes/sec
 Buffer Manager
◦ Buffer cache hit ratio
◦ Page reads / sec
 Buffer Partition
◦ Free Pages
 Cache Manager
◦ Cache Hit Ratio
 Databases
◦ Active Transactions
◦ Data File Size
◦ Log Growths
◦ Percent Log Used
◦ Transactions / sec
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 General Statistics
◦ Logins | logouts / sec
◦ User Connections
 Latches
◦ Latch waits / sec
 Locks
◦ Lock requests / sec
◦ Lock waits / sec
 Memory Manager
◦ Everything!
 Replication
◦ Depends on configuration
 SQL Statistics
◦ Batch requests / sec
◦ SQL compilations / sec

11.  SQL Server Activity Monitor
◦ Provides a quick overview of database server activity
◦ CPU, Processes, Resource Waits and Disk I/O
◦ “Recent Expensive Queries”
 SQL Server Management Studio Reports
◦ Quick overview of SQL Server usage
◦ Can export to Excel or PDF

12. Server-Level Reports Database-Level Reports
 Server Dashboard
 Memory Consumption
 Activity – All Block
Transactions
 Activity – Top Sessions
 Performance – Batch
Execution Statistics
 Performance – Top Queries
by Average CPU
 Object Execution Statistics
 Disk Usage
 All Transactions
 All Blocking Transactions
 Index Usage Statistics
 Top Transactions by Age
 Schema Changes History

13.  Windows Event Logs / Event Viewer
◦ Application and System Event Logs
 SQL Server Management Studio
◦ SQL Server Logs
 Can configure max. # of log files
◦ SQL Server Agent Error logs
 Can configure logging levels (Errors, Warnings, Information)
 Using the Log File Viewer
◦ Can Export / Load log information
◦ Can search for specific errors/messages

14.  Purpose:
◦ Monitoring and troubleshooting
◦ View server state and performance details
◦ Returns relational result sets (use standard SELECT statements)
 Full list can be viewed in “Views  System Views” section
of the properties of the database
 Scopes:
◦ Server level
◦ Database level

15. •sys.dm_exec_requests
Query Execution / Processes
•sys.DM_DB_File_Space_Usage
Storage Engine
•sys.DM_DB_Index_Operational_Stats
•sys.DM_DB_Index_Physical_Stats
Indexes
•sys.DM_IO_Pending_IO_Requests
•sys.DM_IO_Virtual_File_Stats
Disk I/O
•Schema information | Common Language Runtime (CLR)
•Database Mirror / Clustering | Replication
Other Categories

16.  Data Collected:
◦ System Information (MSINFO)
◦ Windows Event Logs
◦ SQL Server configuration
 Command-Line Utility (SQLDiag.exe)
◦ Stores output to files
◦ Configuration file: SQLDiag.xml
◦ Can run as a service (/R)
◦ Can run in continuous mode

17. Monitoring SQL Server Activity

18.  Purpose / Features:
◦ GUI for managing SQL Trace
◦ Monitor important events
◦ Capture performance data / resource usage
◦ Replaying of workloads / transactions
◦ Identifying performance bottlenecks
◦ Correlation of data with System Monitor
◦ Workloads for Database Tuning Advisor
 Examples:
◦ Generate a list of the 100 slowest queries
◦ Monitor all failed logins (Security)

19.  SQL Profiler Terminology
◦ Trace Definitions
◦ Events
◦ Columns
◦ Filters
 Creating and Managing SQL Traces
◦ SQL Profiler (GUI)
◦ System Stored Procedures (Transact-SQL)
 Trace Templates (Built-In)
◦ Standard (Default), SP_Counts
◦ TSQL, TSQL_Duration, TSQL_Grouped,TSQL_Replay, TSQL_SPs
◦ Tuning

20. Anil Desai20
 Trace
◦ A set of events, data columns and filters that specify what data should be
collected
◦ Data can be saved to a file or a database table
 Trace File
◦ Trace data that is saved to a binary file
◦ Default extension is “.trc”
 Trace Table
◦ A SQL Server database table in which trace information is stored
◦ Profiler will automatically create the structure of this table when you start
running a new trace
 Trace Template
◦ Saved specifications that can be used as the basis for new traces
◦ E.g., an environment may have a “Security Monitoring template”, a “CRM
Application Performance”, etc.
◦ Default extension is “.tdf”

21.  Groupings:
◦ Event Categories
◦ Event Classes
◦ Events
 Examples:
◦ TSQL
◦ Stored Procedures
◦ Performance
◦ Errors and Warnings
◦ Security auditing
Event
Categories
Event Classes
Events

22.  Specifies the details to be monitored/recorded
 Configuring columns
◦ Columns can be ordered and grouped
◦ Values can be filtered
 Examples of Columns:
◦ StartTime / EndTime
◦ TextData
◦ Duration
◦ Resource Usage (CPU, Reads, Writes)
◦ Information: User, Database, App. Names

23.  Interactive
◦ Good for “live” monitoring of small sets of data
 Trace Files (*.trc)
◦ Can enable file rollover based on size
◦ “Server processes trace data” option
 Trace table
◦ Will automatically create the table
◦ Can set maximum number of rows
 Scheduling of traces (stop time)

24.  Launching SQL Profiler
 Connecting to a database instance
 Configuring output options
 Create a trace definition
 Specifying events, columns, and filters
 Running and viewing a trace

25.  Creating new templates using SQL Profiler
 Scripting trace definitions
◦ sp_trace_create
◦ sp_trace_setfilter
◦ sp_trace_GenerateEvent
◦ sp_trace_SetEvent
◦ sp_trace_SetStatus
 Extracting SQL Server Events
◦ Transact-SQL Events
◦ ShowPlan Events
◦ Deadlock Events

26.  Purpose / Goal:
◦ Correlate server performance with database performance
 Process:
◦ Define and start a counter log
◦ Define and start a SQL Profiler trace
◦ Import Performance Data in SQL Profiler
 Required Trace properties
◦ StartTime
◦ EndTime

27. Analyzing workloads to optimize
physical database structures

28.  Reviews sample workloads and makes performance
recommendations
 Evaluates Physical Design Structures (PDS)
◦ Indexes (clustered, non-clustered)
◦ Indexed Views
◦ Partitions
 Numerous analysis options
 Output
◦ Generates modification scripts
◦ Generates Reports for later analysis

29.  Files
◦ Transact-SQL Files
◦ XML Files
◦ Should represent commonly-used queries
 SQL Profiler Trace Files / Tables
◦ Use Tuning built-in trace template
◦ Events:
 Transact-SQL Batch
 Remote Procedure Call (RPC)
◦ Columns: Event Class and Text Data

30.  Limit tuning time
 Tuning Options
◦ Allowed Physical Design Structures (PDS)
◦ Keep all/specific existing objects
◦ Maximum storage space
◦ Online or offline recommendations
◦ Partitioning

31.  Reports can be exported to XML files
 Report Examples:
Workload
analysis
Column access Table access
View-Table
Relations
Statement cost Event frequency
Index Usage
(current /
recommended)

32.  Process:
◦ Generate a workload (file or table)
◦ Select tuning options
◦ Run the analysis
◦ View reports
◦ Save and/or apply recommendations
 Running the DTA:
◦ Database Engine Tuning Advisor Application (GUI)
◦ Dta.exe command-line utility

33. Practical ways to improve database
application performance

34.  Create an abstraction layer between the database and
the presentation code
◦ Separates presentation and logic (esp. in Web Apps)
◦ Example: ADO.NET Datasets
 Database design:
◦ Understand typical use-cases before designing the database
◦ Create and enforce naming conventions
◦ Balance write (OLTP) and read (reporting) performance
requirements
◦ Use strategic denormalization
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35.  Never include actions that require user input within a
transaction
 Use connection pooling, whenever possible
◦ Open connections late and close them early
◦ Avoid unnecessary server round-trips
 Use client-side caching whenever possible
◦ Optimistic concurrency
◦ Pessimistic concurrency
 Distribute processing
◦ Some operations are more efficient on the DB server (e.g.,
aggregations, sorting, etc.)

36. Troubleshooting common SQL
Server performance problems

37.  Processes
◦ Interactive users
 SQL Server Management Studio
◦ Applications (Connection Pooling)
 SQL Profiler
 Database Engine Tuning Advisor
 Replication
 Service Broker
 Process IDs < 50 are system-related

38.  SQL Server Activity Monitor
◦ Processes (connected users)
◦ Locks (by Process / by Object)
◦ Filtering options
◦ Auto-refresh option
 System Stored Procedures / Views
◦ Sys.DM_Exec_Sessions
◦ Sys.DM_Exec_Requests
◦ Sys.SysProcesses
◦ sp_who / sp_who2

39.  Process Information
◦ Current Process ID: @@SPID
◦ Session Options: DBCC USEROPTIONS
 Killing Processes
◦ KILL ProcessID [WITH STATUSONLY]
 Viewing Last Activity
◦ DBCC INPUTBUFFER(ProcessID)
◦ DBCC OUTPUTBUFFER(ProcessID)

40.  Coordinates multiple accesses to the same data
 Ensures ACID Properties for transactions (Atomic,
Consistent, Independent, Durable)
 Contention can reduce performance
 Locking granularity:
◦ Row-Level, Page-Level, Table-Level, etc.
 Lock Modes:
◦ Shared, Exclusive, etc.
 Lock escalation

41.  Blocking
◦ When transaction(s) must wait for a lock on a resource
◦ LOCK_TIMEOUT setting (default = wait forever)
 Locking Models:
◦ Pessimistic
◦ Optimistic

42.  Balance of concurrency (performance) vs. consistency
◦ Affects SELECT queries
◦ SET TRANSACTION ISOLATION LEVEL
 Transaction Isolation Levels
◦ READ UNCOMMITTED
◦ READ COMMITTED (default)
◦ REPEATABLE READ
◦ SERIALIZABLE
◦ SNAPSHOT
 Row-Versioning:
◦ ALLOW_SNAPSHOT_ISOLATION
◦ READ_COMMITTED_SNAPSHOT

43.  Activity Monitor
 SQL Profiler
◦ Locks Event Category
 System Monitor:
◦ SQL Server  Locks Object
 System Views
◦ Sys.DM_Tran_Locks
◦ Sys.DM_Exec_Requests
 System Stored Procedures
◦ sp_Lock

44.  Deadlocks:
◦ Two or more tasks permanently block each other based on
resource locks
◦ Default resolution is within 5 seconds
 Deadlock victim
◦ Transaction is rolled-back
◦ Process receives a 1205 error
 Example:
◦ Process 1 locks the Customers table and requires access to
the Orders Table
◦ Process 2 locks the Orders table and requires access to the
Customers Table

45.  Minimize transaction times
◦ Commit / Rollback transactions as quickly as possibly
◦ Avoid user-related time within a transaction
 Access objects in a consistent order
 Change the transaction isolation level
◦ Use a lower level isolation level, if appropriate
◦ Use snapshot-based isolation levels

46.  Deadlock priorities:
◦ SET DEADLOCK_PRIORITY (LOW, NORMAL, HIGH,
integer)
 Deadlock resolution:
◦ Lower priority is killed first
◦ If equal priorities, least expensive transaction becomes the
victim
◦ Application or user should attempt to re-run the transaction

47.  SQL Server Error Log
 SQL Profiler
◦ Locks Event Category
 Lock:Deadlock Chain
 Lock:Deadlock
 Deadlock Graph
◦ Events Extraction Trace Property
◦ Export deadlock XML (.xdl) file
 Viewing Deadlock Files
◦ SQL Server Management Studio (File  Open  SQL
Deadlock Files (*.xdl)

49. For more information:
http://AnilDesai.net
Anil@AnilDesai.net