sys.database_files (Transact-SQL)

Artykuł
02/13/2015

Contains a row per file of a database as stored in the database itself. This is a per-database view.

Column name	Data type	Description
file_id	int	ID of the file within database.
file_guid	uniqueidentifier	GUID for the file. NULL = Database was upgraded from an earlier version of SQL Server.
type	tinyint	File type: 0 = Rows (Includes files of full-text catalogs that are upgraded to or created in SQL Server 2012.) 1 = Log 2 = FILESTREAM 3 = Identified for informational purposes only. Not supported. Future compatibility is not guaranteed. 4 = Full-text (Full-text catalogs earlier than SQL Server 2012; full-text catalogs that are upgraded to or created in SQL Server 2012 will report a file type 0.)
type_desc	nvarchar(60)	Description of the file type: ROWS (Includes files of full-text catalogs that are upgraded to or created in SQL Server 2012.) LOG FILESTREAM FULLTEXT (Full-text catalogs earlier than SQL Server 2012.)
data_space_id	int	Value can be 0 or greater than 0. A value of 0 represents the database log file, and a value greater than 0 represents the ID of the filegroup where this data file is stored.
name	sysname	Logical name of the file in the database.
physical_name	nvarchar(260)	Operating-system file name. If the database is hosted by an AlwaysOn readable secondary replica, physical_name indicates the file location of the primary replica database. For the correct file location of a readable secondary database, query sys.sysaltfiles.
state	tinyint	File state: 0 = ONLINE 1 = RESTORING 2 = RECOVERING 3 = RECOVERY_PENDING 4 = SUSPECT 5 = Identified for informational purposes only. Not supported. Future compatibility is not guaranteed. 6 = OFFLINE 7 = DEFUNCT
state_desc	nvarchar(60)	Description of the file state: ONLINE RESTORING RECOVERING RECOVERY_PENDING SUSPECT OFFLINE DEFUNCT For more information, see File States.
size	int	Current size of the file, in 8-KB pages. 0 = Not applicable For a database snapshot, size reflects the maximum space that the snapshot can ever use for the file. For FILESTREAM filegroup containers, size reflects the current used size of the container.
max_size	int	Maximum file size, in 8-KB pages: 0 = No growth is allowed. -1 = File will grow until the disk is full. 268435456 = Log file will grow to a maximum size of 2 TB. [!UWAGA] Databases that are upgraded with an unlimited log file size will report -1 for the maximum size of the log file. For FILESTREAM filegroup containers, max_size reflects the maximum size of the container.
growth	int	0 = File is fixed size and will not grow. >0 = File will grow automatically. If is_percent_growth = 0, growth increment is in units of 8-KB pages, rounded to the nearest 64 KB. If is_percent_growth = 1, growth increment is expressed as a whole number percentage.
is_media_read_only	bit	1 = File is on read-only media. 0 = File is on read-write media.
is_read_only	bit	1 = File is marked read-only. 0 = File is marked read/write.
is_sparse	bit	1 = File is a sparse file. 0 = File is not a sparse file. For more information, see View the Size of the Sparse File of a Database Snapshot (Transact-SQL).
is_percent_growth	bit	1 = Growth of the file is a percentage. 0 = Absolute growth size in pages.
is_name_reserved	bit	1 = Dropped file name (name or physical_name) is reusable only after the next log backup. When files are dropped from a database, the logical names stay in a reserved state until the next log backup. This column is relevant only under the full recovery model and the bulk-logged recovery model.
create_lsn	numeric(25,0)	Log sequence number (LSN) at which the file was created.
drop_lsn	numeric(25,0)	LSN at which the file was dropped. 0 = The file name is unavailable for reuse.
read_only_lsn	numeric(25,0)	LSN at which the filegroup that contains the file changed from read/write to read-only (most recent change).
read_write_lsn	numeric(25,0)	LSN at which the filegroup that contains the file changed from read-only to read/write (most recent change).
differential_base_lsn	numeric(25,0)	Base for differential backups. Data extents changed after this LSN will be included in a differential backup.
differential_base_guid	uniqueidentifier	Unique identifier of the base backup on which a differential backup will be based.
differential_base_time	datetime	Time corresponding to differential_base_lsn.
redo_start_lsn	numeric(25,0)	LSN at which the next roll forward must start. Is NULL unless state = RESTORING or state = RECOVERY_PENDING.
redo_start_fork_guid	uniqueidentifier	Unique identifier of the recovery fork. The first_fork_guid of the next log backup restored must match this value. This represents the current state of the file.
redo_target_lsn	numeric(25,0)	LSN at which the online roll forward on this file can stop. Is NULL unless state = RESTORING or state = RECOVERY_PENDING.
redo_target_fork_guid	uniqueidentifier	The recovery fork on which the file can be recovered. Paired with redo_target_lsn.
backup_lsn	numeric(25,0)	The LSN of the most recent data or differential backup of the file.

[!UWAGA]

When you drop or rebuild large indexes, or drop or truncate large tables, the Database Engine defers the actual page deallocations, and their associated locks, until after the transaction commits. Deferred drop operations do not release allocated space immediately. Therefore, the values returned by sys.database_files immediately after dropping or truncating a large object may not reflect the actual disk space available.