What’s New in SQL Server System and Database Administration
System Administrator Responsibilities
System Databases
System Tables
System Views
System Stored Procedures
Summary
8 Installing SQL Server 2008
What’s New in Installing SQL Server 2008
Installation Requirements
Installation Walkthrough
Installing SQL Server Using a Configuration File
Installing Service Packs and Cumulative Updates
Slipstream Installations
Summary
9 Upgrading to SQL Server 2008
What’s New in Upgrading SQL Server
Using the SQL Server Upgrade Advisor (UA)
Destination: SQL Server 2008 or SQL Server 2008 R2
Upgrading Using a Configuration File
Slipstreaming Upgrades
Upgrading Other SQL Server Components
Summary
10 Client Installation and Configuration
What’s New in Client Installation and Configuration
Client/Server Networking Considerations
Client Installation
Client Configuration
Client Data Access Technologies
Summary
11 Security and User Administration
What’s New in Security and User Administration
An Overview of SQL Server Security
Authentication Methods
Managing Principals
Managing Securables
Managing Permissions
Managing SQL Server Logins
Managing SQL Server Users
Managing Database Roles
Managing SQL Server Permissions
The Execution Context
Summary
12 Data Encryption
What’s New in Data Encryption
An Overview of Data Security
An Overview of Data Encryption
SQL Server Key Management
Column-Level Encryption
Transparent Data Encryption
Column-Level Encryption Versus Transparent Data Encryption
Summary
13 Security and Compliance
Exposure and Risk
Across the Life Cycle
The Security Big Picture
Identity Access Management Components
Compliance and SQL Server
SQL Server Auditing
Setting Up Auditing via T-SQL
SQL Injection Is Easy to Do
Summary
14 Database Backup and Restore
What’s New in Database Backup and Restore
Developing a Backup and Restore Plan
Types of Backups
Recovery Models
Backup Devices
Backing Up a Database
Backing Up the Transaction Log
Backup Scenarios
Restoring Databases and Transaction Logs
Restore Scenarios
Additional Backup Considerations
Summary
15 Database Mail
What’s New in Database Mail
Setting Up Database Mail
Sending and Receiving with Database Mail
Using SQL Server Agent Mail
Related Views and Procedures
Summary
16 SQL Server Scheduling and Notification
What’s New in Scheduling and Notification
Configuring the SQL Server Agent
Viewing the SQL Server Agent Error Log
SQL Server Agent Security
Managing Operators
Managing Jobs
Managing Alerts
Scripting Jobs and Alerts
Multiserver Job Management
Event Forwarding
Summary
17 Administering SQL Server 2008 with PowerShell
What’s New with PowerShell
Overview of PowerShell
PowerShell Scripting Basics
PowerShell in SQL Server 2008
Step-By-Step Examples
Summary
18 SQL Server High Availability
What’s New in High Availability
What Is High Availability?
The Fundamentals of HA
Building Solutions with One or More HA Options
Other HA Techniques That Yield Great Results
High Availability from the Windows Server Family Side
Summary
19 Replication
What’s New in Data Replication
What Is Replication?
The Publisher, Distributor, and Subscriber Magazine Metaphor
Replication Scenarios
Subscriptions
Replication Agents
Planning for SQL Server Data Replication
SQL Server Replication Types
Basing the Replication Design on User Requirements
Setting Up Replication
Scripting Replication
Monitoring Replication
Summary
20 Database Mirroring
What’s New in Database Mirroring
What Is Database Mirroring?
Roles of the Database Mirroring Configuration
Setting Up and Configuring Database Mirroring
Testing Failover from the Principal to the Mirror
Client Setup and Configuration for Database Mirroring
Migrate to Database Mirroring 2008 as Fast as You Can
Using Replication and Database Mirroring Together
Using Database Snapshots from a Mirror for Reporting
Summary
21 SQL Server Clustering
What’s New in SQL Server Clustering
How Microsoft SQL Server Clustering Works
Installing SQL Server Clustering
Summary
22 Administering Policy-Based Management
Introduction to Policy-Based Management
Policy-Based Management Concepts
Implementing Policy-Based Management
Sample Templates and Real-World Examples
Policy-Based Management Best Practices
Summary
Part IV: Database Administration
23 Creating and Managing Databases
What’s New in Creating and Managing Databases
Data Storage in SQL Server
Database Files
Creating Databases
Setting Database Options
Managing Databases
Summary
24 Creating and Managing Tables
What’s New in SQL Server 2008
Creating Tables
Defining Columns
Defining Table Location
Defining Table Constraints
Modifying Tables
Dropping Tables
Using Partitioned Tables
Creating Temporary Tables
Summary
25 Creating and Managing Indexes
What’s New in Creating and Managing Indexes
Types of Indexes
Creating Indexes
Managing Indexes
Dropping Indexes
Online Indexing Operations
Indexes on Views
Summary
26 Implementing Data Integrity
What’s New in Data Integrity
Types of Data Integrity
Enforcing Data Integrity
Using Constraints
Rules
Defaults
Summary
27 Creating and Managing Views in SQL Server
What’s New in Creating and Managing Views
Definition of Views
Using Views
Creating Views
Managing Views
Data Modifications and Views
Partitioned Views
Indexed Views
Summary
28 Creating and Managing Stored Procedures
What’s New in Creating and Managing Stored Procedures
Advantages of Stored Procedures
Creating Stored Procedures
Executing Stored Procedures
Deferred Name Resolution
Viewing Stored Procedures
Modifying Stored Procedures
Using Input Parameters
Using Output Parameters
Returning Procedure Status
Debugging Stored Procedures Using SQL Server Management Studio
Using System Stored Procedures
Startup Procedures
Summary
29 Creating and Managing User-Defined Functions
What’s New in SQL Server 2008
Why Use User-Defined Functions?
Types of User-Defined Functions
Creating and Managing User-Defined Functions
Rewriting Stored Procedures as Functions
Creating and Using CLR Functions
Summary
30 Creating and Managing Triggers
What’s New in Creating and Managing Triggers
Using DML Triggers
Using DDL Triggers
Using CLR Triggers
Using Nested Triggers
Using Recursive Triggers
Summary
31 Transaction Management and the Transaction Log
What’s New in Transaction Management
What Is a Transaction?
How SQL Server Manages Transactions
Defining Transactions
Transactions and Batches
Transactions and Stored Procedures
Transactions and Triggers
Transactions and Locking
Coding Effective Transactions
Transaction Logging and the Recovery Process
Long-Running Transactions
Bound Connections
Distributed Transactions
Summary
32 Database Snapshots
What’s New with Database Snapshots
What Are Database Snapshots?
Limitations and Restrictions of Database Snapshots
Copy-on-Write Technology
When to Use Database Snapshots
Setup and Breakdown of a Database Snapshot
Reverting to a Database Snapshot for Recovery
Setting Up Snapshots Against a Database Mirror
Database Snapshots Maintenance and Security Considerations
Summary
33 Database Maintenance
What’s New in Database Maintenance
The Maintenance Plan Wizard
Managing Maintenance Plans Without the Wizard
Executing a Maintenance Plan
Maintenance Without a Maintenance Plan
Database Maintenance Policies
Summary
Part V: SQL Server Performance and Optimization
34 Data Structures, Indexes, and Performance
What’s New for Data Structures, Indexes, and Performance
Understanding Data Structures
Database Files and Filegroups
Database Pages
Space Allocation Structures
Data Compression
Understanding Table Structures
Understanding Index Structures
Data Modification and Performance
Index Utilization
Index Selection
Evaluating Index Usefulness
Index Statistics
SQL Server Index Maintenance
Index Design Guidelines
Indexed Views
Indexes on Computed Columns
Filtered Indexes and Statistics
Choosing Indexes: Query Versus Update Performance
Identifying Missing Indexes
Identifying Unused Indexes
Summary
35 Understanding Query Optimization
What’s New in Query Optimization
What Is the Query Optimizer?
Query Compilation and Optimization
Query Analysis
Row Estimation and Index Selection
Join Selection
Execution Plan Selection
Query Plan Caching
Other Query Processing Strategies
Parallel Query Processing
Common Query Optimization Problems
Managing the Optimizer
Summary
36 Query Analysis
What’s New in Query Analysis
Query Analysis in SSMS
SSMS Client Statistics
Using the SET SHOWPLAN Options
Using sys.dm_exec_query_plan
Query Statistics
Query Analysis with SQL Server Profiler
Summary
37 Locking and Performance
What’s New in Locking and Performance
The Need for Locking
Transaction Isolation Levels in SQL Server
The Lock Manager
Monitoring Lock Activity in SQL Server
SQL Server Lock Types
SQL Server Lock Granularity
Lock Compatibility
Locking Contention and Deadlocks
Table Hints for Locking
Optimistic Locking
Summary
38 Database Design and Performance
What’s New in Database Design and Performance
Basic Tenets of Designing for Performance
Logical Database Design Issues
Denormalizing a Database
Database Filegroups and Performance
RAID Technology
SQL Server and SAN Technology
Summary
39 Monitoring SQL Server Performance
What’s New in Monitoring SQL Server Performance
Performance Monitoring Tools
A Performance Monitoring Approach
Summary
40 Managing Workloads with the Resource Governor
Overview of Resource Governor
Resource Governor Components
Configuring Resource Governor
Monitoring Resource Usage
Modifying Your Resource Governor Configuration
Summary
41 A Performance and Tuning Methodology
The Full Architectural Landscape
Primary Performance and Tuning Handles
A Performance and Tuning Methodology
Performance and Tuning Design Guidelines
Tools of the Performance and Tuning Trade
Summary
Part VI: SQL Server Application Development
42 What’s New for Transact-SQL in SQL Server 2008
MERGE Statement
Insert over DML
GROUP BY Clause Enhancements
Variable Assignment in DECLARE Statement
Compound Assignment Operators
Row Constructors
New date and time Data Types and Functions
Table-Valued Parameters
Hierarchyid Data Type
Using FILESTREAM Storage
Sparse Columns
Spatial Data Types
Change Data Capture
Change Tracking
Summary
43 Transact-SQL Programming Guidelines, Tips, and Tricks
General T-SQL Coding Recommendations
General T-SQL Performance Recommendations
T-SQL Tips and Tricks
In Case You Missed It: New Transact-SQL Features in SQL Server 2005
The xml Data Type
The max Specifier
TOP Enhancements
The OUTPUT Clause
Common Table Expressions
Ranking Functions
PIVOT and UNPIVOT
The APPLY Operator
TRY...CATCH Logic for Error Handling
The TABLESAMPLE Clause
Summary
44 Advanced Stored Procedure Programming and Optimization
T-SQL Stored Procedure Coding Guidelines
Using Cursors in Stored Procedures
Nested Stored Procedures
Using Temporary Tables in Stored Procedures
Using Remote Stored Procedures
Stored Procedure Performance
Using Dynamic SQL in Stored Procedures
Installing and Using .NET CLR Stored Procedures
Using Extended Stored Procedures
Summary
45 SQL Server and the .NET Framework
What’s New in SQL Server 2008 and the .NET Framework
Getting Comfortable with ADO.NET 3.5 and SQL Server 2008
Developing with LINQ to SQL
Using ADO.NET Data Services
Leveraging the Microsoft Sync Framework
Summary
46 SQLCLR: Developing SQL Server Objects in .NET
What’s New for SQLCLR in SQL Server 2008
Developing Custom Managed Database Objects
Summary
47 Using XML in SQL Server 2008
What’s New in Using XML in SQL Server 2008
Understanding XML
Relational Data As XML: The FOR XML Modes
XML As Relational Data: Using OPENXML
Using the xml Data Type
Indexing and Full-Text Indexing of xml Columns
Summary
48 SQL Server Web Services
What’s New in SQL Server Web Services
Web Services Migration Path
Web Services History and Overview
Building Web Services
Examples: A C# Client Application
Using Catalog Views and System Stored Procedures
Controlling Access Permissions
Summary
49 SQL Server Service Broker
What’s New in Service Broker
Understanding Distributed Messaging
Designing a Sample System
Understanding Service Broker Constructs
Service Broker Routing and Security
Troubleshooting SSB Applications with ssbdiagnose.exe
Related System Catalogs
Summary
50 SQL Server Full-Text Search
What’s New in SQL Server 2008 Full-Text Search
Upgrade Options in SQL Server 2008
How SQL Server FTS Works
Implementing SQL Server 2008 Full-Text Catalogs
Setting Up a Full-Text Index
Full-Text Searches
Full-Text Search Maintenance
Full-Text Search Performance
Full-Text Search Troubleshooting
Summary
Part VII: SQL Server Business Intelligence Features
51 SQL Server 2008 Analysis Services
What’s New in SSAS
Understanding SSAS and OLAP
Understanding the SSAS Environment Wizards
An Analytics Design Methodology
An OLAP Requirements Example: CompSales International
Summary
52 SQL Server Integration Services
What’s New with SSIS
SSIS Basics
SSIS Architecture and Concepts
SSIS Tools and Utilities
A Data Transformation Requirement
Running the SSIS Wizard
The SSIS Designer
The Package Execution Utility
Connection Projects in Visual Studio
Change Data Capture Addition with R2
Using bcp
Logged and Nonlogged Operations
Summary
53 SQL Server 2008 Reporting Services
What’s New in SSRS 2008
Reporting Services Architecture
Installing and Configuring SSRS
Developing Reports
Management and Security
Performance and Monitoring
Summary
Part VIII: Bonus Chapters
54 Managing Linked and Remote Servers
What’s New in Managing Linked and Remote Servers
Managing Remote Servers
Linked Servers
Adding, Dropping, and Configuring Linked Servers
Mapping Local Logins to Logins on Linked Servers
Obtaining General Information About Linked Servers
Executing a Stored Procedure via a Linked Server
Setting Up Linked Servers Using SQL Server Management Studio
Summary
55 Configuring, Tuning, and Optimizing SQL Server Options
What’s New in Configuring, Tuning, and Optimizing SQL Server Options
SQL Server Instance Architecture
Configuration Options
Fixing an Incorrect Option Setting
Setting Configuration Options with SSMS
Obsolete Configuration Options
Configuration Options and Performance
Database Engine Tuning Advisor
Data Collection Sets
Summary
56 SQL Server Disaster Recovery Planning
What’s New in SQL Server Disaster Recovery Planning
How to Approach Disaster Recovery
Microsoft SQL Server Options for Disaster Recovery
The Overall Disaster Recovery Process
Have You Detached a Database Recently?
Third-Party Disaster Recovery Alternatives
Summary
Index
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D
E
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K
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ptg 1094 CHAPTER 34 Data Structures, Indexes, and Performance SQL Server uses the file location information visible in the sys.master_files catalog view most of the time. However, the Database Engine uses the file location information stored in the primary file to initialize the file location entries in the master database when attaching a database using the CREATE DATABASE statement with either the FOR ATTACH or FOR ATTACH_REBUILD_LOG options. Every database can have three types of files: . Primary data file . Secondary data files . Log files In addition, in SQL Server 2008, databases can also have FILESTREAM data files and full- text data files. TABLE 34.1 The sysfiles Table Column Name Description file_id A file identification number that is unique within each database file_guid GUID for the file type File type (0=rows [that is, data files], 1=log, 2=FILESTREAM, 4=Full-text catalogs prior to SQL Server 2008 type_desc Description of the file type (ROWS, LOG, FILESTREAM, FULLTEXT) data_space_id 0 represents a log file; values > 0 represent the ID of the filegroup the data file belongs to name The logical name of the file filename The physical name of the file, including path state File state (0 = OFFLINE, 1 = RESTORING, 2 = RECOVERING, 3 = RECOVERY_PENDING, 4 = SUSPECT, 6 = OFFLINE, 7=DEFUNCT) state_desc Description of the file state (OFFLINE, RESTORING, RECOVERING, RECOVERY_PENDING, SUSPECT, OFFLINE, DEFUNCT) size Current size of the file in 8KB pages max_size Maximum file size in 8KB pages growth File growth setting (0=fixed, >0=autogrow in units of 8KB pages or by percentage if is_percent_growth is set to 1) is_media_read_only 1=file is on read-only media is_read_only 1= file is marked read-only is_sparse 1=file is a sparse file is_percent_growth 1=growth of file value is percentage Download from www.wowebook.com ptg 1095 Database Files and Filegroups 34 Primary Data File Every database has only one primary database file. The location of the primary database file is stored in the master database (visible via the filename column in the sys.master_files view). When SQL Server opens a database, it looks for this file and then reads from the file information on the other files defined for the database. The file extension for the primary database file defaults to .mdf. The primary database file always belongs to the default filegroup. It is often sufficient to have only one database file for storing your tables and indexes (the primary database file). The file can, of course, be created on a RAID partition to help spread I/O. However, if you need finer control over placement of your tables across disks or disk arrays, or if you want to be able to back up only a portion of your database via filegroups, you can create additional, secondary data files for a database. Secondary Data Files A database can have any number of secondary files (in reality, the maximum number of files per database is 32,767, but that should be sufficient for most implementations). You can put a secondary file in the default filegroup or in another filegroup defined for the database. Secondary data files have the file extension.ndf by default. Following are some situations in which the use of secondary database files might be beneficial: . You want to perform a partial backup. A backup can be performed for the entire database or a subset of the database. The subset is specified as a set of files or file- groups. The partial backup feature is useful for large databases, where it is impracti- cal to back up the entire database. When recovering with partial backups, a transaction log backup must also be available. For more information about backups, see Chapter 14, “Database Backup and Restore.” . You want more control over placement of database objects. When you create a table or index, you can specify the filegroup in which the object is created. This could help you spread I/O by placing your most active tables or indexes on separate file- groups defined on separate disks or disk arrays. . Creating multiple files on a single disk provides no real performance benefit but could help in recovery. If you have a 90GB database in a single file and have to restore it, you need to have enough disk space available to create a new 90GB file. If you don’t have 90GB of space available on a single disk, you cannot restore the data- base. On the other hand, if the database was created with three files each 30GB in size, you more likely will be able to find three 30GB chunks of space available on your server. Download from www.wowebook.com ptg 1096 CHAPTER 34 Data Structures, Indexes, and Performance The Log File Each database must have at least one log file. The log file contains the transaction log records of all changes made in a database (for more information on what is contained in the transaction log, see Chapter 31, “Transaction Management and the Transaction Log”). By default, log files have the file extension .ldf. A database can have several log files, and each log file can have a maximum size of 32TB. A log file cannot be part of a filegroup. No information other than transaction log records can be written to a log file. For more information on the log file and log file management, see Chapter 31. File Management In SQL Server 2008, you can specify that a database file should grow automatically as space is needed. SQL Server can also shrink the size of the database if the space is not needed. You can control whether to use this feature along with the increment by which the file is to be expanded. The increment can be specified as a fixed number of megabytes or as a percentage of the current size of the file. You can also set a limit on the maximum size of the file or allow it to grow until no more space is available on the disk. Listing 34.1 provides an example of a database being created with a 10MB growth increment for the first database file, 20MB for the second, and 20% growth increment for the log file. LISTING 34.1 Creating a Database with Autogrowth CREATE DATABASE Customer ON ( NAME=’Customer_Data’, FILENAME=’D:\SQL_data\Customer_Data1.mdf’, SIZE=50, MAXSIZE=100, FILEGROWTH=10), ( NAME=’Customer_Data2’, FILENAME=’E:\SQL_data\Customer_Data2.ndf’, SIZE=100, FILEGROWTH=20) LOG ON ( NAME=’Customer_Log’, FILENAME=’F:\SQL_data\Customer_Log.ldf’, SIZE=50, FILEGROWTH=20%) GO The Customer_Data file has an initial size of 50MB, a maximum size of 100MB, and a file increment of 10MB. The Customer_Data2 file has an initial size of 100MB, has a file growth increment of 20MB, and can grow until the E: disk partition is full. Download from www.wowebook.com ptg 1097 Database Files and Filegroups 34 The transaction log has an initial size of 50MB; the file increases by 20% with each file growth. The increment is based on the current file size, not the size originally specified. When creating or expanding data files in SQL Server 2008, SQL Server uses fast file initial- ization. This allows for the fast execution of the file creation and growth. With fast file initialization, the space is added to the data file immediately, but without initializing the logical pages in the data file with zeros. The existing disk content in the data file is not overwritten until new data is written to the files. This provides a huge performance advan- tage when a data file autogrows while an application is attempting to write data to the database. The application does not need to wait until the space is initialized; it can begin writing to the database immediately. SQL Server also provides an option to autoshrink databases as well as manually shrink databases. However, shrinking a database is a resource-intensive process and should be done only if it is absolutely imperative to reclaim disk space. Also, if a data file is constantly shrinking and growing, it can lead to excessive file fragmentation at the file system level as well as excessive logical fragmentation within the file, both of which can lead to poor I/O performance. Using Filegroups All databases have a primary filegroup that contains the primary data file. There can be only one primary filegroup. If you don’t create any other filegroups or change the default filegroup to a filegroup other than the primary filegroup, all files will be in the primary file group unless specifically placed in another filegroup. In addition to the primary filegroup, you can add one or more filegroups to the database, and a filegroup can contain one or more files. The main purpose of using filegroups is to provide more control over the placement of files and data on your server. When you create a table or index, you can map it to a specific filegroup, thus controlling the place- ment of data. A typical SQL Server database installation generally uses a single RAID array to spread I/O across disks and create all files in the primary filegroup; more advanced installations or installations with very large databases spread across multiple array sets can benefit from the finer level of control of file and data placement afforded by additional filegroups. For example, for a simple database such as AdventureWorks, you can create just one primary file that contains all data and objects and a log file that contains the transaction log information. For a larger and more complex database, such as a securities trading system where large data volumes and strict performance criteria are the norm, you might create the database with one primary file and four additional secondary files. You can then set up filegroups so you can place the data and objects within the database across all five files. If you have a table that itself needs to be spread across multiple disk arrays for perfor- mance reasons, you can place multiple files in a filegroup, each of which resides on a different disk, and create the table on that filegroup. For example, you can create three files ( Data1.ndf, Data2.ndf, and Data3.ndf) on three disk arrays, respectively, and then Download from www.wowebook.com ptg 1098 CHAPTER 34 Data Structures, Indexes, and Performance assign them to the filegroup called spread_group. Your table can then be created specifi- cally on the filegroup spread_group. Queries for data from the table are spread across the three disk arrays, thereby improving I/O performance. If a filegroup contains more than one file, when space is allocated to objects stored in that filegroup, the data is stored proportionally across the files. In other words, if you have one file in a filegroup with twice as much free space as another, the first file has two extents allocated from it for each extent allocated from the second file (extents and space alloca- tion are discussed in more detail later in this chapter). Listing 34.2 provides an example of using filegroups in a database to control the file place- ment of the customer_info table. LISTING 34.2 Using a Filegroup to Control Placement for a Table CREATE DATABASE Customer ON ( NAME=’Customer_Data’, FILENAME=’C:\SQLData\Customer_Data1.mdf’, SIZE=50, MAXSIZE=100, FILEGROWTH=10) LOG ON ( NAME=’Customer_Log’, FILENAME=’C:\SQLData\Customer_Log.ldf’, SIZE=50, FILEGROWTH=20%) GO ALTER DATABASE Customer ADD FILEGROUP Cust_table GO ALTER DATABASE Customer ADD FILE ( NAME=’Customer_Data2’, FILENAME=’G:\SQLData\Customer_Data2.ndf’, SIZE=100, FILEGROWTH=20) TO FILEGROUP Cust_Table GO USE Customer CREATE TABLE customer_info (cust_no INT, cust_address NCHAR(200), info NVARCHAR(3000)) ON Cust_Table GO Download from www.wowebook.com ptg 1099 Database Files and Filegroups 34 TABLE 34.2 The sys.filegroups System Catalog View Column Name Description name Name of the data space, unique within the database. data_space_id Data space ID number, unique within the database. type FG = Filegroup. type_desc Description of data space type: ROWS_FILEGROUP. is_default 1 = This is the default data space. The default data space is used when a file- group or partition scheme is not specified in a CREATE TABLE or CREATE INDEX statement. 0 = This is not the default data space. filegroup_guid GUID for the filegroup. NULL = PRIMARY filegroup. log_filegroup_id Not used; value is NULL. is_read_only 1 = Filegroup is read-only. 0 = Filegroup is read/write. The CREATE DATABASE statement in Listing 34.2 creates a database with a primary database file and log file. The first ALTER DATABASE statement adds a filegroup. A secondary data- base file is added with the second ALTER DATABASE command. This file is added to the Cust_Table filegroup. The CREATE TABLE statement creates a table; the ON Cust_Table clause places the table in the Cust_Table filegroup (the Customer_Data2 file on the G: disk partition). The sys.filegroups system catalog view contains information about the database file- groups defined within a database, as shown in Table 34.2. The following statement returns the filename, size in megabytes (not including autogrow), and the name of the filegroup to which each file belongs: SELECT convert(varchar(30), sf.name) as filename, size/128 as size_in_MB, convert(varchar(30), sfg.name) as filegroupname FROM sys.database_files sf INNER JOIN sys.filegroups sfg ON sf.data_space_id = sfg.data_space_id Download from www.wowebook.com ptg 1100 CHAPTER 34 Data Structures, Indexes, and Performance go filename size_in_MB filegroupname Customer_Data 50 PRIMARY Customer_Data2 100 Cust_table FILESTREAM Filegroups FILESTREAM storage is a new feature in SQL Server 2008 for storing unstructured data, such as documents, images, and videos. FILESTREAM storage helps to solve the issues with using unstructured data by integrating the SQL Server Database Engine with the NTFS file system for storing the unstructured data, such as documents and images, on the file system with the database storing a pointer to the data. Although the actual data resides outside the database in the NTFS file system, you can still use Transact-SQL (T-SQL) statements to insert, update, query, and back up FILESTREAM data, while maintaining transactional consistency between the unstructured data and corresponding structured data with same level of security. NOTE To use FILESTREAM storage, you must first enable FILESTREAM storage at the Windows level as well as at the SQL Server instance level. You can enable FILESTREAM at the Windows level during installation of SQL Server 2008 or at any time using SQL Server Configuration Manager. After you enable FILESTREAM at the Windows level, you next need to enable FILESTREAM for the SQL Server instance. You can do this either through SQL Server Management Studio (SSMS) or via T-SQL. After you enabled FILESTREAM for the SQL Server instance, you can enable it for a data- base by creating a FILESTREAM filegroup. You can do this when the database is created (or to an existing database) by adding a filegroup and including the CONTAINS FILESTREAM clause. Unlike regular filegroups, a FILESTREAM filegroup can contain only a single file reference, which is actually a file system folder rather than an actual file. The actual folder must not exist (although the path up to the folder must exist); SQL Server creates the filestream folder. For example, in Listing 34.3, the code adds a FILESTREAM filegroup called CustFSGroup and adds the folder G:\SQLData\custinfo_FS into the file group. This custinfo_FS folder is created by SQL Server in the G:\SQLData folder. LISTING 34.3 Using a Filegroup to Control Placement for a Table ALTER DATABASE Customer ADD FILEGROUP Cust_FSGroup CONTAINS FILESTREAM ALTER DATABASE Customer Download from www.wowebook.com ptg 1101 Database Pages 34 ADD FILE ( NAME=custinfo_FS, FILENAME = ‘G:\SQLData\custinfo_FS’) to FILEGROUP Cust_FSGroup GO If you look in the G:\SQLData\custinfo_FS folder, you should see a Filestream.hdr file and an $FSLOG folder. The Filestream.hdr file is a FILESTREAM container header file that should not be moved or modified. As you can see in the example in Listing 34.3, for FILESTREAM files or file groups, unlike regular files, you do not specify size or growth information. No space is preallocated. The file and filegroup grow as data is added to tables that have been created with FILESTREAM columns. As you create tables with FILESTREAM columns, a subfolder is created in the filegroup folder for each table. The filenames are GUIDs. Each FILESTREAM column created in the table results in another subfolder created under the table subfolder. The column subfolder name is also a GUID. At this point, there still are no actual files created. That happens after you start adding rows to the table. A file is created in the column subfolder for each row inserted into the table with a non- NULL value for the FILESTREAM column. For more information on creating and using tables with FILESTREAM columns, see Chapter 42, “What’s New for Transact-SQL in SQL Server 2008.” Database Pages All information in SQL Server is stored at the page level. The page is the smallest level of I/O in SQL Server and is the fundamental storage unit. Pages contain the data itself or information about the physical layout of the data. The page size is the same for all page types: 8KB, or 8,192 bytes. The pages are arranged in two basic types of storage structures: linked data pages and index trees. Databases are divided into logical 8KB pages. Within each file allocated to a database, the pages are numbered contiguously from 0 to n. The actual number of pages in the database file depends on the size of the file. Pages in a database are uniquely referenced by specify- ing the database ID, the file ID for the file the page resides in, and the page number within the file. When you expand a database with ALTER DATABASE, the new space is added at the end of the file, and the page numbers continue incrementing from the previ- ous last page in the file. If you add a completely new file, its first page number is 0. When you shrink a database, pages are removed from the end of the file only, starting at the highest page in the database and moving toward lower-numbered pages until the database reaches the specified size or a used page that cannot be removed. This ensures that page numbers within a file are always contiguous. Download from www.wowebook.com ptg 1102 CHAPTER 34 Data Structures, Indexes, and Performance TABLE 34.3 Page Types Page Type Stores Data Data rows for all data except text, ntext, image, nvarchar(max), varchar(max), varbinary(max), and xml data Row Overflow Data columns that cause a data row to exceed the 8,060 bytes per page limit LOB Large object types (text, ntext, image, nvarchar(max), varchar(max), varbinary(max), xml data, and varchar, nvarchar, varbinary, and sqlvariant when data row size exceeds 8KB) Index Index entries and pointers Global Allocation Map Information about allocated (used) extents Page Free Space Information about page allocation and free space on pages Index Allocation Map Information about extents used by a table or an index Differential Changed Map Information about which extents have been modified since the last full database backup Bulk Changed Map Information about which extents have been used in a minimally logged or bulk-logged operation since the last BACKUP LOG statement Body Header 96 byte header 8096 bytes 8K PagE (8192Bytes) FIGURE 34.1 SQL Server page layout. Page Types There are eight page types in SQL Server, as listed in Table 34.3. All pages, regardless of type, have a similar layout. They all have a page header, which is 96 bytes, and a body, which consequently is 8,096 bytes. The page layout is shown in Figure 34.1. Download from www.wowebook.com ptg 1103 Database Pages 34 Data Pages The actual data rows in tables are stored on data pages. Figure 34.2 shows the basic struc- ture of a data page. The following sections discuss and examine the contents of the data page. The Page Header The page header contains control information for the page. Some fields assist when SQL Server checks for consistency among its storage structures, and some fields are used when navigating among the pages that constitute a table. Table 34.4 describes the more useful fields contained in the page header. Header Row Offset Table . . . 96118140 … … Row 0 Row 1 Row 2 Byte Address Row ID0 1 2 96 118 140 0 34 8095 FIGURE 34.2 The structure of a SQL Server data page. Download from www.wowebook.com . “What’s New for Transact -SQL in SQL Server 2008. ” Database Pages All information in SQL Server is stored at the page level. The page is the smallest level of I/O in SQL Server and is the fundamental. enable FILESTREAM for the SQL Server instance. You can do this either through SQL Server Management Studio (SSMS) or via T -SQL. After you enabled FILESTREAM for the SQL Server instance, you can. Windows level as well as at the SQL Server instance level. You can enable FILESTREAM at the Windows level during installation of SQL Server 2008 or at any time using SQL Server Configuration Manager.