Dynamic Management Views and Dynamic Management Functions - Microsoft SQL Server 2012 Performance Tuning - page 140

All DMVs and DMFs are located in the sys schema and all DMVs and DMFs have a common
naming convention, which is dm_* . This prefix is generally followed by a category prefix to
which a DMV or DMF belongs, which is followed by the name of DMV or DMF.
Executing these DMVs and DMFs requires VIEW SERVER STATE
and VIEW DATABASE STATE permissions.
The following section discusses some of the categories of DMVs and DMFs that we will cover
in this topic:
F Execution-specific DMVs and DMFs ( sys.dm_exec_* ): This category provides the
statistics related to query execution. These DMVs and DMFs can be used to monitor
statistics pertaining to the cached queries, execution plans, active connections/
sessions, and currently running queries along with their execution plans.
F Index-specific DMVs and DMFs ( sys.dm_db_index_* and sys.dm_db_
missing_* ): This category provides the statistics related to indexes. These DMVs
and DMFs can be used to monitor and troubleshoot the performance of the indexes
by finding missing indexes, unused indexes and examining the index usage statistics.
F Database-specific DMVs and DMFs ( sys.dm_db_* ): This category provides the
statistics related to databases. These DMVs and DMFs can be used to monitor and
troubleshoot the performance of databases by analyzing the database-specific file
statistics, session statistics, and task statistics.
F I/O-specific DMVs and DMFs ( sys.dm_io_* ): This category provides the statistics
related to I/O operations. These DMVs and DMFs can be used to monitor and
troubleshoot the I/O performance of SQL Server.
F OS-specific DMVs and DMFs ( sys.dm_os_* ): This category provides the statistics
related to SQL OS internals. These DMVs can be used to monitor and troubleshoot
the server configuration issues.
F Transaction-specific DMVs and DMFs ( sys.dm_tran_* ): This category provides the
statistics related to transactions. These DMVs and DMFs can be used to monitor and
troubleshoot the locking and blocking issues caused by long-running transactions.
The statistics provided by dynamic management views and dynamic
management functions are not persistent. These statistics, for most
of the DMVs and DMFs, are reset when SQL Server is restarted
or DBCC SQLPERF ('sys.dm_os_wait_stats', CLEAR)
command is executed.