ptg 174 CHAPTER 7 SQL Server System and Database Administration TABLE 7.2 SQL Server 2008 Alternatives for SQL Server 2000 System Tables SQL Server 2000 System Table SQL Server 2008 System View View Type sys.foreign_keys Catalog view syscurconfigs sys.configurations Catalog view sysdatabases sys.databases Catalog view sysdepends sys.sql_dependencies Catalog view sysdevices sys.backup_devices Catalog view sysfilegroups sys.filegroups Catalog view sysfiles sys.database_files Catalog view sysforeignkeys sys.foreign_keys Catalog view sysfulltextcatalogs sys.fulltext_catalogs Catalog view sysindexes sys.indexes Catalog view sys.partitions Catalog view sys.allocation_units Catalog view sys.dm_db_partition_stats DMV sysindexkeys sys.index_columns Catalog view syslanguages sys.syslanguages Compatibility view syslockinfo sys.dm_tran_locks DMV syslocks sys.dm_tran_locks DMV syslogins sys.sql_logins (transact-sql) Catalog view sysmembers sys.database_role_members Catalog view sysmessages sys.messages Catalog view sysobjects sys.objects Catalog view sysoledbusers sys.linked_logins Catalog view sysopentapes sys.dm_io_backup_tapes DMV sysperfinfo sys.dm_os_performance_counters DMV syspermissions sys.database_permissions Catalog view sys.server_permissions Catalog view sysprocesses sys.dm_exec_connections DMV Download from www.wowebook.com ptg 175 System Views 7 TABLE 7.2 SQL Server 2008 Alternatives for SQL Server 2000 System Tables SQL Server 2000 System Table SQL Server 2008 System View View Type sys.dm_exec_sessions DMV sys.dm_exec_requests DMV sysprotects sys.database_permissions Catalog view sys.server_permissions Catalog view sysreferences sys.foreign_keys Catalog view sysremotelogins sys.remote_logins Catalog view sysservers sys.servers Catalog view systypes sys.types Catalog view sysusers sys.database_principals Catalog view Catalog Views Using catalog views is the preferred method for returning information used by the Microsoft SQL Server database engine. There is a catalog view to return information about almost every aspect of SQL Server. The number of catalog views is far too large to list here, but you can gain some insight into the range of information available by looking at the following list, which shows the categories of information covered by catalog views: . Change Tracking . Common language runtime (CLR) assembly . Data spaces and full text . Database mirroring . Data spaces . Endpoint . Extended properties . Linked servers . Messages (for errors) . Objects . Partition function . Resource Governor . Scalar types . Schemas Download from www.wowebook.com ptg 176 CHAPTER 7 SQL Server System and Database Administration . Security . Server-wide configuration . Service Broker . SQL Server Extended Events . XML schemas (XML type system) Some of the catalog views return information that is new to SQL Server 2008. Examples include the Change Tracking and Resource Governor catalog views. Other catalog views provide information that may have been available in prior versions through system tables, system procedures, and so on, but the new catalog views expand on the information returned and include elements that are new to SQL Server 2008. To demonstrate the use of a catalog view, let’s compare a simple SQL Server 2000 SELECT statement that returns object information to a SELECT statement in SQL Server 2008 that returns similar information. The following example shows a SELECT statement written in SQL Server 2000 to return any stored procedure created after a given date: select o.crdate, o.name from sysobjects o where type = ‘p’ and crdate > ‘1/1/08’ order by crdate, name Now, compare this SELECT statement to one that uses a SQL Server 2008 catalog view. The sys.objects catalog view is a new alternative to the SQL Server 2000 sysobjects system table. The following SELECT uses the sys.objects catalog view to return the same type of information as the preceding example: select o.create_date, o.modify_date, name from sys.objects o where type = ‘p’ and (create_date > ‘1/1/08’ or o.modify_date >= ‘1/1/08’) order by 1, 2, 3 As you can see, the modify_date column has been added to the SELECT statement. This column did not exist with the sysobjects system table. The addition of this column allows you to identify objects that were created as well as objects that were modified or altered. Let’s look at an example of using a catalog view to return the same kind of information returned in SQL Server 2000 with a system procedure. The handy sp_helpfile system procedure returns information about database files associated with a given database. This SQL Server 2000 procedure is still available in SQL Server 2008. An alternative to this procedure is the new sys.master_files catalog view. This view returns all the information that sp_helpfile returns and more. The following example shows a SELECT statement Download from www.wowebook.com ptg 177 System Views 7 using the sys.master_files catalog view to return the database files for the AdventureWorks2008R2 database: select * from sys.master_files where db_name(database_id) = ‘AdventureWorks2008R2’ You have the distinct advantage of being able to select the database files for all the data- bases on your server by using this catalog view. You can also tailor your SELECT statement to isolate database files based on the size of the database or the location of the physical database files. For example, to return all database files that are found somewhere on your C drive, you could use the following SELECT: select db_name(database_id), physical_name from sys.master_files where physical_name like ‘c:\%’ There are plenty of catalog views that provide information about SQL Server. When you are looking to return information about SQL Server components, you should look to the catalog views first. These views provide a great deal of flexibility and allow you to isolate the specific information you need. Information Schema Views Information schema views provide another system table–independent option for accessing SQL Server metadata. This type of view was available in prior versions of SQL Server. Using information schema views is a viable alternative for accessing SQL Server metadata from a production application. The information schema views enable an application that uses them to function properly even though the underlying system tables may have changed. Changes to the underlying system tables are most prevalent when a new version of SQL Server is released (such as SQL Server 2008), but changes can also occur as part of service packs to an existing version. The information schema views also have the advantage of being SQL-92 compatible. Compliance with the SQL-92 standard means that SQL statements written against these views work with other DBMSs that also adhere to the SQL-92 standard. The SQL-92 stan- dard supports a three-part naming convention, which SQL Server has implemented as database.schema.object. In SQL Server 2008, all the information schema views are in the same schema, named INFORMATION_SCHEMA. The following information schema views or objects are available: . CHECK_CONSTRAINTS . COLUMN_DOMAIN_USAGE . COLUMN_PRIVILEGES . COLUMNS . CONSTRAINT_COLUMN_USAGE Download from www.wowebook.com ptg 178 CHAPTER 7 SQL Server System and Database Administration . CONSTRAINT_TABLE_USAGE . DOMAIN_CONSTRAINTS . DOMAINS . KEY_COLUMN_USAGE . PARAMETERS . REFERENTIAL_CONSTRAINTS . ROUTINES . ROUTINE_COLUMNS . SCHEMATA . TABLE_CONSTRAINTS . TABLE_PRIVILEGES . TABLES . VIEW_COLUMN_USAGE . VIEW_TABLE_USAGE . VIEWS When you refer to information schema views in a SQL statement, you must use a qualified name that includes the schema name. For example, the following statement returns all the tables and columns in a given database, using the tables and columns information schema views: select t.TABLE_NAME, c.COLUMN_NAME from INFORMATION_SCHEMA.TABLES t join INFORMATION_SCHEMA.COLUMNS c on t.TABLE_NAME = c.TABLE_NAME order by t.TABLE_NAME, ORDINAL_POSITION TIP You can expand the Views node in a given database in the Object Explorer and open the System Views node to see a list of the available information schema views. The information schema views are listed at the top of the System Views node. If you expand the Column node under each information schema view, you see the available columns to select from the view. You can then drag the column into a query window for use in a SELECT statement. You can also use IntelliSense in a query window determine the columns. Fortunately, the names of the information schema views are fairly intuitive and reflect the kind of information they contain. The relationships between the information schema views can be derived from the column names shared between the tables. Download from www.wowebook.com ptg 179 System Views 7 Dynamic Management Views Dynamic management views (DMVs), which were introduced in SQL Server 2005, provide a simple means for assessing the state of a server. These views provide a lightweight means for gathering diagnostic information without the heavy burden associated with the tools available in SQL Server 2000. The SQL Server 2000 diagnostic tools, such as heavy Profiler traces, PerfMon, dbcc executions, and pssdiag, are still available, but oftentimes, the information returned from the DMVs is enough to determine what may be ailing a SQL Server machine. An extensive number of DMVs are available in SQL Server 2008. Some DMVs are scoped at the server level, and others are scoped at the database level. They are all found in the sys schema and have names that start with dm_. Table 7.3 lists the different types of DMVs. The DMVs in this table are categorized based on function as well as the starting characters in the DMV names. The naming convention gives you an easy means for identifying the type of each DMV. TABLE 7.3 Types of DMVs Category Name Prefix Information Captured Auditing dm_audit New Auditing information Service Broker dm_broker Server Broker statistics, including activated tasks and connections Change Data dm_cdc New Change Data Capture information CLR dm_clr CLR information, including the CLR loaded assemblies Cryptographic dm_cryp Security related data TDE dm_database Transparent D ata Encr yption Database dm_db Databases and database objects Execution dm_exec Execution of user code Full-Text dm_fts Full-Text Search information I/O dm_io Input and output on network disks Operating system dm_os Low-level operating system information, including memory and locking information Provider dm_provider Extensible Key Management (EKM) Query Notification dm_qn Active Query Notification subscriptions Replication dm_repl Replication information, including the articles, publications, and transaction involved in replication Download from www.wowebook.com ptg 180 CHAPTER 7 SQL Server System and Database Administration TABLE 7.3 Types of DMVs Category Name Prefix Information Captured Server dm_server Server Audit status Transaction dm_tran Transactions and isolati on-leve l information Object dm_sql Object References Extended Events dm_xe New event handling infrastructure TIP You can expand the Views node in a given database in the Object Explorer and open the System Views node to see a list of the available DMVs. The DMVs are all listed together and start with dm_. If you expand the Column node under each DMV, you see the available columns to select from the view. You can then drag the column into a query window to be included in a SELECT statement. To illustrate the value of the DMVs, let’s look at a performance scenario and compare the SQL Server 2000 approach to a SQL Server 2008 approach using DMVs. A common performance- related question is “What stored procedures are executing most frequently on my server?” With SQL Server 2000, the most likely way to find out is to run a Profiler trace. You must have a Profiler trace that has already been running to capture the stored procedure executions, or you must create a new trace and run it for a period of time to answer the performance ques- tion. The trace takes time to create and can affect server performance while it is running. With SQL Server 2008, you can use one of the DMVs in the execution category to answer the same performance question. The following example uses the sys.dm_exec_query_stats DMV along with a dynamic management function named dm_exec_sql_text. It returns the object IDs of the five most frequently executed stored procedures, along with the actual text associated with the procedure: select top 5 q.execution_count, q.total_worker_time, s.dbid, s.objectid, s.text from sys.dm_exec_query_stats q CROSS APPLY sys.dm_exec_sql_text (q.sql_handle) s ORDER BY q.execution_count desc The advantage of using a DMV is that it can return past information without having to explic- itly create a trace or implement some other performance tool. SQL Server automatically caches the information so that you can query it at any time. The collection of the data starts when the SQL Server instance is started, so you can get a good cross-section of information. Keep in mind that your results can change as the server continues to collect information over time. Many of the performance scenarios such as those that relate to memory, CPU utilization, blocking, and recompilation can be investigated using DMVs. You should consider using Download from www.wowebook.com ptg 181 System Views 7 DMVs to address performance problems before using other methods in SQL Server 2008. In many cases, you may be able to avoid costly traces and glean enough information from the DMV to solve your problem. NOTE Dynamic management functions return the same type of information as DMVs. The dynamic management functions also have names that start with dm_ and reside in the sys schema. You can find the dynamic management functions listed in the Object Explorer within the master database. If you select Function, System Functions, Table- Valued Functions, you see the dynamic management functions listed at the top. DMVs are also a great source of information that does not relate directly to performance. For example, you can use the dm_os_sys_info DMV to gather important server informa- tion, such as the number of CPUs, the amount of memory, and so on. The following example demonstrates the use of the dm_os_sys_info DMV to return CPU and memory information: select cpu_count, hyperthread_ratio, physical_memory_in_bytes from sys.dm_os_sys_info /* Results from prior select cpu_count hyperthread_ratio physical_memory_in_bytes 2 2 2146357248 */ The cpu_count column returns the number of logical CPUs, hyperthread_ratio returns the ratio between physical CPUs and logical CPUs, and the last column selected returns the physical memory on the SQL Server machine. System Stored Procedures System stored procedures have been a favorite of SQL Server DBAs since the inception of SQL Server. They provide a rich set of information that covers many different aspects of SQL Server. They can return some of the same types of information as system views, but they generally return a fixed set of information that cannot be modified as you can when using a SELECT statement against the system views. That is not to say that they are not valuable; they are valuable, and they are particularly useful for people who have been using SQL Server for a long time. System stored procedures such as sp_who, sp_lock, and sp_help are tools for a database professional that are as basic as a hammer is to a carpenter. System stored procedures have names that start with sp_, and they are found in the sys schema. They are global in scope, which allows you to execute them from any database, Download from www.wowebook.com ptg 182 CHAPTER 7 SQL Server System and Database Administration TABLE 7.4 Useful System Stored Procedures System Stored Procedure Description sp_configure Displays or changes server-wide configuration settings. sp_createstats Creates statistics that are used by the Query Optimizer for all tables in a database. sp_help Provides details about the object that is passed to it. If a table name is passed to this procedure, it returns information on the columns, constraints, indexes, and more. sp_helpdb If no parameters are supplied, returns relevant database information (including the space used) for all the databases on an instance of SQL Server. without qualifying the stored procedure name. They also run in the context of the data- base where you are working. In other words, if you execute sp_helpfile in the AdventureWorks2008R2 database, the database files for the AdventureWorks2008R2 database are returned. This same type of behavior exists for any stored procedure that is created in the master database with a name that starts with sp_. For example, if you create a proce- dure named sp_helpme in the master database and execute that procedure in the AdventureWorks2008R2 database, SQL Server ultimately looks for and finds the procedure in the master database. NOTE It is often useful to create your own system stored procedures to make it easier to exe- cute complex queries against the system views (or to provide information not provided by the built-in system procedures). For more information and tips on creating your own system stored procedures, refer to Chapter 28, “Creating and Managing Stored Procedures.” System stored procedures are listed in the Object Explorer, in the Programmability node within Stored Procedures and then System Stored Procedures. There are far too many system stored procedures to list or discuss them all here. A quick check of the master database lists more than 1,000 procedures. SQL Server Books Online provides detailed help on these procedures, which it groups into 18 different categories. Useful System Stored Procedures You are likely to use only a handful of system stored procedures on a regular basis. What procedures you use depends on the type of work you do with SQL Server and your capac- ity to remember their names. Table 7.4 contains a sample set of system stored procedures that you may find useful. Download from www.wowebook.com ptg 183 System Stored Procedures 7 Many of the administrative functions performed by SSMS can also be accomplished with system stored procedures. Examples include procedures that start with sp_add and sp_delete, which can be used to add and delete database objects. In addition, more than 90 system stored procedures start with sp_help, which return help information on database objects. TIP You can use the sys.all_objects catalog view to search for available system stored procedures. This catalog view lists objects that are schema scoped as well as system objects. For example, the query SELECT * FROM sys.all_objects WHERE name LIKE ‘sp_help%’ returns all the system stored procedures that start with sp_help. You can turn to Books Online for detailed help on any of the system stored procedures. Just enter sp_ in the index search, and you see a list of them all. Becoming familiar with some of the system stored procedures is well worth your while. Using them is a very fast and effective means for gathering information from SQL Server. They do not require the formation of a SELECT statement, and using them is often the easiest way to get information via a query window. Summary Administering SQL Server can be a complex and time-consuming job. Understanding the SQL Server internals and some of the easy ways to obtain information about a SQL Server instance can make this job a lot easier. Taking the time to learn what makes SQL Server tick expands your knowledge of this comprehensive DBMS and helps you make better decisions when working with it. Now that you know a bit about managing SQL Server, you may need to install an instance of SQL Server to administer. Take a look at Chapter 8, “Installing SQL Server 2008,” which guides you through the installation process. TABLE 7.4 Useful System Stored Procedures System Stored Procedure Description sp_helpfile Lists the database files associated with the database you are connected to. sp_lock Displays current locking information for the entire SQL Server instance. sp_spaceused Provides the number of rows and disk space used by the table, indexed view, or queue passed to it. sp_who Lists current processes that are connected to an instance of SQL Server. Download from www.wowebook.com . ptg 174 CHAPTER 7 SQL Server System and Database Administration TABLE 7.2 SQL Server 2008 Alternatives for SQL Server 2000 System Tables SQL Server 2000 System Table SQL Server 2008 System View. to SQL Server 2008. To demonstrate the use of a catalog view, let’s compare a simple SQL Server 2000 SELECT statement that returns object information to a SELECT statement in SQL Server 2008. the SQL Server 2000 approach to a SQL Server 2008 approach using DMVs. A common performance- related question is “What stored procedures are executing most frequently on my server? ” With SQL Server