Search This Blog

Determining when statistics were last updated in SQL Server?

Rebuild all indexes on all tables in the SQL Server database


1) Through the header information using DBCC SHOW_STATISTICS
The syntax lets you specify a table or indexed view along with a target index name, statistics name, or column name (see below):
1
2
3
4
5
6
7
8
USE [<Database_Name>]
GO
 
DBCC SHOW_STATISTICS (table_or_indexed_view_name
                     ,index_or_statistics_name_coloumn_name')
[ WITH [ NO_INFOMSGS ] < option > [ , n ] ]
< option > :: =
    STAT_HEADER | DENSITY_VECTOR | HISTOGRAM | STATS_STREAM
Example: Returning all statistics information
The following example returns all statistics information for theIXC_ServerChecks_Results_LoadID index of the ServerChecks.Results table.
1
2
3
4
5
USE [SQLComplianceDW]
GO
 
DBCC SHOW_STATISTICS('ServerChecks.Results'
                     ,IXC_ServerChecks_Results_LoadID)
01
The first result set of the DBCC SHOW_STATISTICS command returns the header information, including when the statistics were last updated. To only return the header information about the statistic, you executed DBCC SHOW_STATISTICS with STATS_HEADER option.
1
2
3
4
USE [SQLComplianceDW]
GO
 
DBCC SHOW_STATISTICS('ServerChecks.Results', IXC_ServerChecks_Results_LoadID) WITH STAT_HEADER;
02
Note that STAT_HEADER, HISTOGRAM and DENSITY_VECTOR options are only available in SQL Server 2005 and later releases.
As you can see from above example, DBCC SHOW_STATISTICS returns statistics information for the index name, statistics name, or column name of the specified table or in indexed view, however, if you only want to see the statistics update date for all statistics objects that exists for the tables, indexes, and indexed views in the database, you query sys.stats and useSTATS_DATE() function.
2) Through STATS_DATE() function and sys.stats system catalog view
To determine date when the statistics where last updated, you execute sys.stats system catalog view with STATS_DATE() function, as follow:
1
2
3
4
SELECT OBJECT_NAME(object_id) AS [ObjectName]
      ,[name] AS [StatisticName]
      ,STATS_DATE([object_id], [stats_id]) AS [StatisticUpdateDate]
FROM sys.stats;
03
As you can see, this query returns date of the most recent update for statistics on a table or indexed view.

Rebuild all indexes on all tables in the SQL Server database

Generate the script for Rebuilt indexes for all tables, and dynamically generate and execute ALTER INDEX statements. This script is compatible with SQL Server 2005 and above versions.
Here is this script:

--/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
--Arguments             Data Type               Description
--------------          ------------            ------------
--@FillFactor           [int]                   Specifies a percentage that indicates how full the Database Engine should make the leaf level
--                                              of each index page during index creation or alteration. The valid inputs for this parameter
--                                              must be an integer value from 1 to 100 The default is 0.
--                                              For more information, see http://technet.microsoft.com/en-us/library/ms177459.aspx.
 
--@PadIndex             [varchar](3)            Specifies index padding. The PAD_INDEX option is useful only when FILLFACTOR is specified,
--                                              because PAD_INDEX uses the percentage specified by FILLFACTOR. If the percentage specified
--                                              for FILLFACTOR is not large enough to allow for one row, the Database Engine internally
--                                              overrides the percentage to allow for the minimum. The number of rows on an intermediate
--                                              index page is never less than two, regardless of how low the value of fillfactor. The valid
--                                              inputs for this parameter are ON or OFF. The default is OFF.
--                                              For more information, see http://technet.microsoft.com/en-us/library/ms188783.aspx.
 
--@SortInTempDB         [varchar](3)            Specifies whether to store temporary sort results in tempdb. The valid inputs for this
--                                              parameter are ON or OFF. The default is OFF.
--                                              For more information, see http://technet.microsoft.com/en-us/library/ms188281.aspx.
 
--@OnlineRebuild        [varchar](3)            Specifies whether underlying tables and associated indexes are available for queries and data
--                                              modification during the index operation. The valid inputs for this parameter are ON or OFF.
--                                              The default is OFF.
--                                              Note: Online index operations are only available in Enterprise edition of Microsoft
--                                                      SQL Server 2005 and above.
--                                              For more information, see http://technet.microsoft.com/en-us/library/ms191261.aspx.
 
--@DataCompression      [varchar](4)            Specifies the data compression option for the specified index, partition number, or range of
--                                              partitions. The options  for this parameter are as follows:
--                                                  > NONE - Index or specified partitions are not compressed.
--                                                  > ROW  - Index or specified partitions are compressed by using row compression.
--                                                  > PAGE - Index or specified partitions are compressed by using page compression.
--                                              The default is NONE.
--                                              Note: Data compression feature is only available in Enterprise edition of Microsoft
--                                                      SQL Server 2005 and above.
--                                              For more information about compression, see http://technet.microsoft.com/en-us/library/cc280449.aspx.
 
--@MaxDOP               [int]                   Overrides the max degree of parallelism configuration option for the duration of the index
--                                              operation. The valid input for this parameter can be between 0 and 64, but should not exceed
--                                              number of processors available to SQL Server.
--                                              For more information, see http://technet.microsoft.com/en-us/library/ms189094.aspx.
--- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -*/
 
-- Ensure a USE <databasename> statement has been executed first.
 
SET NOCOUNT ON;
 
DECLARE  @Version                           [numeric] (18, 10)
        ,@SQLStatementID                    [int]
        ,@CurrentTSQLToExecute              [nvarchar](max)
        ,@FillFactor                        [int]        = 100 -- Change if needed
        ,@PadIndex                          [varchar](3) = N'OFF' -- Change if needed
        ,@SortInTempDB                      [varchar](3) = N'OFF' -- Change if needed
        ,@OnlineRebuild                     [varchar](3) = N'OFF' -- Change if needed
        ,@LOBCompaction                     [varchar](3) = N'ON' -- Change if needed
        ,@DataCompression                   [varchar](4) = N'NONE' -- Change if needed
        ,@MaxDOP                            [int]        = NULL -- Change if needed
        ,@IncludeDataCompressionArgument    [char](1);
 
IF OBJECT_ID(N'TempDb.dbo.#Work_To_Do') IS NOT NULL
    DROP TABLE #Work_To_Do
CREATE TABLE #Work_To_Do
    (
      [sql_id] [int] IDENTITY(1, 1)
                     PRIMARY KEY ,
      [tsql_text] [varchar](1024) ,
      [completed] [bit]
    )
 
SET @Version = CAST(LEFT(CAST(SERVERPROPERTY(N'ProductVersion') AS [nvarchar](128)), CHARINDEX('.', CAST(SERVERPROPERTY(N'ProductVersion') AS [nvarchar](128))) - 1) + N'.' + REPLACE(RIGHT(CAST(SERVERPROPERTY(N'ProductVersion') AS [nvarchar](128)), LEN(CAST(SERVERPROPERTY(N'ProductVersion') AS [nvarchar](128))) - CHARINDEX('.', CAST(SERVERPROPERTY(N'ProductVersion') AS [nvarchar](128)))), N'.', N'') AS [numeric](18, 10))
 
IF @DataCompression IN (N'PAGE', N'ROW', N'NONE')
    AND (
        @Version >= 10.0
        AND SERVERPROPERTY(N'EngineEdition') = 3
        )
BEGIN
    SET @IncludeDataCompressionArgument = N'Y'
END
 
IF @IncludeDataCompressionArgument IS NULL
BEGIN
    SET @IncludeDataCompressionArgument = N'N'
END
 
INSERT INTO #Work_To_Do ([tsql_text], [completed])
SELECT 'ALTER INDEX [' + i.[name] + '] ON' + SPACE(1) + QUOTENAME(t2.[TABLE_CATALOG]) + '.' + QUOTENAME(t2.[TABLE_SCHEMA]) + '.' + QUOTENAME(t2.[TABLE_NAME]) + SPACE(1) + 'REBUILD WITH (' + SPACE(1) + + CASE
        WHEN @PadIndex IS NULL
            THEN 'PAD_INDEX =' + SPACE(1) + CASE i.[is_padded]
                    WHEN 1
                        THEN 'ON'
                    WHEN 0
                        THEN 'OFF'
                    END
        ELSE 'PAD_INDEX =' + SPACE(1) + @PadIndex
        END + CASE
        WHEN @FillFactor IS NULL
            THEN ', FILLFACTOR =' + SPACE(1) + CONVERT([varchar](3), REPLACE(i.[fill_factor], 0, 100))
        ELSE ', FILLFACTOR =' + SPACE(1) + CONVERT([varchar](3), @FillFactor)
        END + CASE
        WHEN @SortInTempDB IS NULL
            THEN ''
        ELSE ', SORT_IN_TEMPDB =' + SPACE(1) + @SortInTempDB
        END + CASE
        WHEN @OnlineRebuild IS NULL
            THEN ''
        ELSE ', ONLINE =' + SPACE(1) + @OnlineRebuild
        END + ', STATISTICS_NORECOMPUTE =' + SPACE(1) + CASE st.[no_recompute]
        WHEN 0
            THEN 'OFF'
        WHEN 1
            THEN 'ON'
        END + ', ALLOW_ROW_LOCKS =' + SPACE(1) + CASE i.[allow_row_locks]
        WHEN 0
            THEN 'OFF'
        WHEN 1
            THEN 'ON'
        END + ', ALLOW_PAGE_LOCKS =' + SPACE(1) + CASE i.[allow_page_locks]
        WHEN 0
            THEN 'OFF'
        WHEN 1
            THEN 'ON'
        END + CASE
        WHEN @IncludeDataCompressionArgument = N'Y'
            THEN CASE
                    WHEN @DataCompression IS NULL
                        THEN ''
                    ELSE ', DATA_COMPRESSION =' + SPACE(1) + @DataCompression
                    END
        ELSE ''
        END + CASE
        WHEN @MaxDop IS NULL
            THEN ''
        ELSE ', MAXDOP =' + SPACE(1) + CONVERT([varchar](2), @MaxDOP)
        END + SPACE(1) + ')'
    ,0
FROM [sys].[tables] t1
INNER JOIN [sys].[indexes] i ON t1.[object_id] = i.[object_id]
    AND i.[index_id] > 0
    AND i.[type] IN (1, 2)
INNER JOIN [INFORMATION_SCHEMA].[TABLES] t2 ON t1.[name] = t2.[TABLE_NAME]
    AND t2.[TABLE_TYPE] = 'BASE TABLE'
INNER JOIN [sys].[stats] AS st WITH (NOLOCK) ON st.[object_id] = t1.[object_id]
    AND st.[name] = i.[name]
 
SELECT @SQLStatementID = MIN([sql_id])
FROM #Work_To_Do
WHERE [completed] = 0
 
WHILE @SQLStatementID IS NOT NULL
BEGIN
    SELECT @CurrentTSQLToExecute = [tsql_text]
    FROM #Work_To_Do
    WHERE [sql_id] = @SQLStatementID
 
    PRINT @CurrentTSQLToExecute
 
    EXEC [sys].[sp_executesql] @CurrentTSQLToExecute
 
    UPDATE #Work_To_Do
    SET [completed] = 1
    WHERE [sql_id] = @SQLStatementID
 
    SELECT @SQLStatementID = MIN([sql_id])
    FROM #Work_To_Do
    WHERE [completed] = 0
END