Hướng dẫn học Microsoft SQL Server 2008 part 93 docx

Configuring SQL ServerIN THIS CHAPTER Making sense of SQL Server configuration Configuring the server-level configuration options Configuring the database-level configuration options Con

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Configuring SQL Server

IN THIS CHAPTER Making sense of SQL Server configuration

Configuring the server-level configuration options Configuring the database-level configuration options

Configuring the connection-level options

SQL Server has a plethora of configuration options The difficulty in

master-ing them lies in the fact that they are spread across three levels:

■ Server-level options generally configure how the server works with

hardware, and determine the database defaults

■ Database-level options determine the behavior of the database, and set

the connection-level defaults

■ Connection-level options determine the current behaviors within the

connection or current procedure

Several of the configuration options overlap or simply set the default for the

level immediately below This chapter pulls these three configuration levels into

a single unified understanding of how they relate to and affect each other This

chapter does not cover every single SQL Server configuration option but it covers

most of them that I think are important If you are a SQL Server beginner, you

may find that some of the configuration options are advanced and you may not

need them immediately

Setting the Options

Whether you choose to adjust the properties from SQL Server Management

Studio’s graphical tool or from code is completely up to you, but not every

property is available from Management Studio using the graphical interface

While the graphical interface has the advantage of being easy to use, and walks

you through easily understood dialogs that prompt for the possible options in

a pick-and-choose format, it lacks the repeatability of a T-SQL script run as a

query

To view miscellaneous information about the com-puter system while configuring SQL Server, query the

sys.dm_os_sys_info dynamic management view.

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Part VI Enterprise Data Management

New in SQL Server 2008 Configuration

SQL Server 2008 offers many new configuration options, such as backup compression default

and filestream access level, that give the SQL DBA much more control in configuring SQL

Server 2008

The configuration options set working set size, open objects, and locks are still present in the

sp_configure stored procedure, but their functionality is unavailable in SQL Server 2008 These options

have no effect

Configuring the server

The server-level configuration options control server-wide settings, such as how SQL Server interacts

with hardware, how it multi-threads within Windows, and whether triggers are permitted to fire other

triggers When configuring the server, keep in mind the goals of configuration: consistency and

perfor-mance

Graphically, many of the server options may be configured within the Server Properties page, which you

can open by right-clicking a server in the console tree and choosing Properties from the context menu

The General tab in Management Studio’s SQL Server Properties dialog (see Figure 39-1) reports the

ver-sions and environment of the server

The same information is available to code For example, the version may be identified with the

@@VERSIONglobal variable:

select @@VERSION;

Result:

Microsoft SQL Server 2008 (RTM) - 10.0.1600.22 (Intel X86)

The first line of the preceding result includes the product version of SQL Server In this example, the

SQL Server product version is 10.0.1600.22 The last line of the result can be confusing It reports the

edition of SQL Server In this example, it is SQL Server 2008 Enterprise Edition, but the service pack

reported in the last line is the Windows service pack level and not the SQL Server service pack level

In this example, it is SP2 for Windows Server 2003 That is one of the reasons why I don’t like to use

theSELECT @@VERSIONcommand Instead, I prefer to use theSERVERPROPERTYsystem function to

determine the information The advantage of this method is that the function may be used as an

expres-sion within aSELECTstatement The following example uses theSERVERPROPERTYfunction to return

the SQL Server product version, product level, and edition:

SELECT SERVERPROPERTY(’ProductVersion’) AS ProductVersion, SERVERPROPERTY(’ProductLevel’) AS ProductLevel, SERVERPROPERTY(’Edition’) AS Edition;

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FIGURE 39-1

The General tab of Management Studio’s Server Properties dialog

Result:

ProductVersion ProductLevel Edition

10.0.1600.22 RTM Enterprise Edition

In the preceding result, theProductVersionindicates the SQL Server product version number The

ProductLevelindicates the SQL Server product level At the time of writing this chapter, we did not

have any service packs for SQL Server 2008 and the product level isRTM(Release to Manufacturing)

If a SQL Server service pack is installed, the product level will indicate the service pack level too

For example, if you run the preceding command against your SQL Server 2005 SP3 instance, the

ProductLevelwill return SP3 TheEditionindicates the SQL Server edition

Many of the configuration properties do not take effect until SQL Server is restarted, so the

General tab in the SQL Server Properties (Configure) dialog box displays the current

run-ning values.

Within code, many of the server properties are set by means of thesp_configuresystem stored

pro-cedure When executed without any parameters, this procedure reports the current settings, as in the

following code (word-wrap adjusted to fit on the page):

EXEC sp_configure;

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Result:

run_value - - -

max text repl size (B) −1 2147483647 65536 65536

You can always discover the minimum and maximum values for a particular configuration option by running the sp _ configure command with the option, but without any value For example, run

EXEC sp_configure ‘remote login timeout’;

and you’ll discover that the remote login timeout configuration option can have any value in the

range of 0 to 2,147,483,647.

The extended stored procedurexp_msverreports additional server and environment properties:

EXEC xp_msver;

Result:

((SQL_PreRelease).080709-1414 )

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rights reserved.

a registered trademark of Microsoft Corporation

The information returned by sp_configure is settable, but the information returned by

xp_msver is not.

Configuring the database

The database-level options configure the current database’s behavior regarding ANSI compatibility and

recovery

Most database options can be set in Management Studio within the Database Properties page, which

you can access by right-clicking a database in the console tree and choosing Properties from the context

menu The Options tab is shown in Figure 39-2

The database configuration options can be set using T-SQLALTER DATABASE SEToptions The

follow-ing example sets theAdventureWorks2008database to single-user mode to obtain exclusive access:

ALTER DATABASE AdventureWorks2008 SET SINGLE_USER;

View database configuration options using thesys.databasescatalog view or the

DATABASEPROPERTYEX()function The following example returns all the database properties of

theAdventureWorks2008database:

SELECT * FROM sys.databases WHERE name = ‘AdventureWorks2008’;

Do not use the sp_dboption system stored procedure, as it will be removed in the next

version of SQL Server.

Configuring the connection

Many of the connection-level options configure ANSI compatibility or specific connection-performance

options

Connection-level options are very limited in scope If the option is set within an interactive session, then

the setting is in force until it’s changed or the session ends If the option is set within a stored

proce-dure, then the setting persists only for the life of that stored procedure

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FIGURE 39-2

Management Studio’s Database Properties Options tab can be used to configure the most common

database properties

The connection-level options are typically configured by means of theSETcommand The following

code configures how SQL Server handlesnullswithin this current session:

SET ANSI_NULLS OFF;

Result:

Command(s) completed successfully

Connection properties can also be checked by means of theSessionProperty()function:

Select SESSIONPROPERTY (’ANSI_NULLS’);

Result:

0

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Management Studio allows you to set several query properties You can review and set these properties

for current queries by clicking the Query menu and then Query Options For all future connections,

review and set the properties by clicking the Tools menu and then Options Figure 39-3 shows an

example of the ANSI settings that SQL Server will use to run the queries

To view current settings of connection-level options, query the sys.dm_exec_connections

dynamic management view.

FIGURE 39-3

The ANSI settings that SQL Server uses to run your queries

Configuration Options

Because so many similar configuration options are controlled by different commands and at different

lev-els (server, database, connection), this section organizes the configuration options by topic, rather than

command or level

Displaying the advanced options

As with many operations, displaying advanced options can be achieved using several methods One

method is to query thesys.configurationscatalog view as shown here:

SELECT name, minimum, maximum, value, value_in_use

FROM sys.configurations

WHERE is_advanced = 1

ORDER BY name;

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The preceding example will display all the SQL Server advanced options To display all the options,

comment theWHEREclause Another method to display the advanced options is to turn on theshow

advanced optionsconfiguration, as follows:

EXEC sp_configure ‘show advanced options’, 1;

RECONFIGURE;

After a configuration setting is changed with sp_configure , the RECONFIGURE command causes the changes to take effect If you don’t run RECONFIGURE , then the config_value

field will still show the change, but the change won’t appear in the run_value field, even if you restart

the service Some configuration changes take effect only after SQL Server is restarted.

After you enable the advanced option display, you can use thesp_configurecommand to display a

list of all of the options:

EXEC sp_configure;

Result (with advanced options enabled):

run_value - - - -

default full-text language 0 2147483647 1033 1033

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filestream access level 0 2 2 2

max server memory (MB) 16 2147483647 2147483647

2147483647

65536

min memory per query (KB) 512 2147483647 1024

1024

4096

600

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