sys.dm_db_stats_properties (Transact-SQL)

Article
05/16/2013

Returns properties of statistics for the specified database object (table or indexed view) in the current SQL Server database.

Note

The dynamic management object, sys.dm_db_stats_properties, is available in SQL Server 2012 starting with Service Pack 1 and in SQL Server 2008 R2 starting with Service Pack 2.

Syntax

sys.dm_db_stats_properties (object_id, stats_id)

Arguments

object_id
Is the ID of the object in the current database for which properties of one of its statistics is requested. object_id is int.
stats_id
Is the ID of statistics for the specified object_id. The statistics ID can be obtained from the sys.stats dynamic management view. stats_id is int.

Table Returned

Column name	Data type	Description
object_id	int	ID of the object (table or indexed view) for which to return the properties of the statistics object.
stats_id	int	ID of the statistics object. Is unique within the table or indexed view. For more information, see sys.stats (Transact-SQL).
last_updated	datetime2	Date and time the statistics object was last updated.
rows	bigint	Total number of rows in the table or indexed view when statistics were last updated. If the statistics are filtered or correspond to a filtered index, the number of rows might be less than the number of rows in the table.
rows_sampled	bigint	Total number of rows sampled for statistics calculations.
steps	int	Number of steps in the histogram. For more information, see DBCC SHOW_STATISTICS (Transact-SQL).
unfiltered_rows	bigint	Total number of rows in the table before applying the filter expression (for filtered statistics). If statistics are not filtered, unfiltered_rows is equal to the value returns in the rows column.
modification_counter	bigint	Total number of modifications for the leading statistics column (the column on which the histogram is built) since the last time statistics were updated.

Remarks

sys.dm_db_stats_properties returns an empty rowset under any of the following conditions:

object_id or stats_id is NULL.
The specified object is not found or does not correspond to a table or indexed view.
The specified statistics ID does not correspond to existing statistics for the specified object ID.
The current user does not have permissions to view the statistics object.

This behavior allows for the safe usage of sys.dm_db_stats_properties when cross applied to rows in views such as sys.objects and sys.stats.

Permissions

Requires that the user has select permissions on statistics columns or the user owns the table or the user is a member of the sysadmin fixed server role, the db_owner fixed database role, or the db_ddladmin fixed database role.

Examples

A. Returning all statistics properties for a table

The following example returns properties of all statistics that exist for the table TEST.

SELECT
    sp.stats_id, name, filter_definition, last_updated, rows, rows_sampled, steps, unfiltered_rows, modification_counter 
FROM sys.stats AS stat 
CROSS APPLY sys.dm_db_stats_properties(stat.object_id, stat.stats_id) AS sp
WHERE stat.object_id = object_id('TEST');

B. Returning statistics properties for frequently modified objects

The following example returns all tables, indexed views, and statistics in the current database for which the leading column was modified more than 1000 times since the last statistics update.

SELECT 
    obj.name, obj.object_id, stat.name, stat.stats_id, last_updated, modification_counter
FROM sys.objects AS obj 
JOIN sys.stats stat ON stat.object_id = obj.object_id
CROSS APPLY sys.dm_db_stats_properties(stat.object_id, stat.stats_id) AS sp
WHERE modification_counter > 1000;

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