Identifying Duplicate Indexes

本文是在阅读《Troubleshooting SQL Server》->Chapter 5: Missing Indexes->Identifying Duplicate Indexes时，文中提及两个处理重复索引的链接。此处整理链接文章，方便自己后期查看，详细内容请参考原文：How can you tell if an index is REALLY a duplicate? and Removing duplicate indexes
一、创建新的存储过程，返回表上的索引信息
Step 1: Setup sp_SQLskills_ExposeColsInIndexLevels

/*============================================================================
  File:     sp_SQLskills_ExposeColsInIndexLevels

  Summary:  This procedure lists columns in the key vs. those in the leaf level
            of a nonclustered index. This is dependent on whether or not the
            nonclustered is UNIQUE as well as whether or not the table has a
            clustered index. It also changes based on whether or not the
            clustering key is UNIQUE.

  Date:     May 2010

  Version:    SQL Server 2005/2008
------------------------------------------------------------------------------
  Written by Paul S. Randal and Kimberly L. Tripp, SQLskills.com

  For more scripts and sample code, check out
    http://www.SQLskills.com

  This script is intended only as a supplement to demos and lectures
  given by SQLskills instructors.  

  THIS CODE AND INFORMATION ARE PROVIDED "AS IS" WITHOUT WARRANTY OF
  ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED
  TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
  PARTICULAR PURPOSE.
============================================================================*/

USE master
go

if OBJECTPROPERTY(OBJECT_ID('sp_SQLskills_ExposeColsInIndexLevels'), 'IsProcedure') = 1
    drop procedure sp_SQLskills_ExposeColsInIndexLevels
go

create procedure sp_SQLskills_ExposeColsInIndexLevels
(
    @object_id int,
    @index_id int,
    @ColsInTree nvarchar(2126) OUTPUT,
    @ColsInLeaf nvarchar(max) OUTPUT
)
AS
BEGIN
    declare @nonclus_uniq int
            , @column_id int
            , @column_name nvarchar(260)
            , @col_descending bit
            , @colstr    nvarchar (max);

    -- Get clustered index keys (id and name)
    select sic.column_id, QUOTENAME(sc.name, N']') AS column_name, is_descending_key
    into #clus_keys
    from sys.index_columns AS sic
        JOIN sys.columns AS sc
            ON sic.column_id = sc.column_id AND sc.object_id = sic.object_id
    where sic.[object_id] = @object_id
    and [index_id] = 1;

    -- Get nonclustered index keys
    select sic.column_id, sic.is_included_column, QUOTENAME(sc.name, N']') AS column_name, is_descending_key
    into #nonclus_keys
    from sys.index_columns AS sic
        JOIN sys.columns AS sc
            ON sic.column_id = sc.column_id
                AND sc.object_id = sic.object_id
    where sic.[object_id] = @object_id
        and sic.[index_id] = @index_id;

    -- Is the nonclustered unique?
    select @nonclus_uniq = is_unique
    from sys.indexes
    where [object_id] = @object_id
        and [index_id] = @index_id;

    if (@nonclus_uniq = 0)
    begin
        -- Case 1: nonunique nonclustered index

        -- cursor for nonclus columns not included and
        -- nonclus columns included but also clus keys
        declare mycursor cursor for
            select column_id, column_name, is_descending_key
            from #nonclus_keys
            where is_included_column = 0
        open mycursor;
        fetch next from mycursor into @column_id, @column_name, @col_descending;
        WHILE @@FETCH_STATUS = 0
        begin
            select @colstr = ISNULL(@colstr, N'') + @column_name + CASE WHEN @col_descending = 1 THEN '(-)' ELSE N'' END + N', ';
            fetch next from mycursor into @column_id, @column_name, @col_descending;
        end
        close mycursor;
        deallocate mycursor;

        -- cursor over clus_keys if clustered
        declare mycursor cursor for
            select column_id, column_name, is_descending_key from #clus_keys
            where column_id not in (select column_id from #nonclus_keys
                where is_included_column = 0)
        open mycursor;
        fetch next from mycursor into @column_id, @column_name, @col_descending;
        WHILE @@FETCH_STATUS = 0
        begin
            select @colstr = ISNULL(@colstr, N'') + @column_name + CASE WHEN @col_descending = 1 THEN '(-)' ELSE N'' END + N', ';
            fetch next from mycursor into @column_id, @column_name, @col_descending;
        end
        close mycursor;
        deallocate mycursor;    

        select @ColsInTree = substring(@colstr, 1, LEN(@colstr) -1);

        -- find columns not in the nc and not in cl - that are still left to be included.
        declare mycursor cursor for
            select column_id, column_name, is_descending_key from #nonclus_keys
            where column_id not in (select column_id from #clus_keys UNION select column_id from #nonclus_keys where is_included_column = 0)
        open mycursor;
        fetch next from mycursor into @column_id, @column_name, @col_descending;
        WHILE @@FETCH_STATUS = 0
        begin
            select @colstr = ISNULL(@colstr, N'') + @column_name + CASE WHEN @col_descending = 1 THEN '(-)' ELSE N'' END + N', ';
            fetch next from mycursor into @column_id, @column_name, @col_descending;
        end
        close mycursor;
        deallocate mycursor;    

        select @ColsInLeaf = substring(@colstr, 1, LEN(@colstr) -1);

    end

    -- Case 2: unique nonclustered
    else
    begin
        -- cursor over nonclus_keys that are not includes
        select @colstr = ''
        declare mycursor cursor for
            select column_id, column_name, is_descending_key from #nonclus_keys
            where is_included_column = 0
        open mycursor;
        fetch next from mycursor into @column_id, @column_name, @col_descending;
        WHILE @@FETCH_STATUS = 0
        begin
            select @colstr = ISNULL(@colstr, N'') + @column_name + CASE WHEN @col_descending = 1 THEN '(-)' ELSE N'' END + N', ';
            fetch next from mycursor into @column_id, @column_name, @col_descending;
        end
        close mycursor;
        deallocate mycursor;

        select @ColsInTree = substring(@colstr, 1, LEN(@colstr) -1);

        -- start with the @ColsInTree and add remaining columns not present...
        declare mycursor cursor for
            select column_id, column_name, is_descending_key from #nonclus_keys
            WHERE is_included_column = 1;
        open mycursor;
        fetch next from mycursor into @column_id, @column_name, @col_descending;
        WHILE @@FETCH_STATUS = 0
        begin
            select @colstr = ISNULL(@colstr, N'') + @column_name + CASE WHEN @col_descending = 1 THEN '(-)' ELSE N'' END + N', ';
            fetch next from mycursor into @column_id, @column_name, @col_descending;
        end
        close mycursor;
        deallocate mycursor;

        -- get remaining clustered column as long as they're not already in the nonclustered
        declare mycursor cursor for
            select column_id, column_name, is_descending_key from #clus_keys
            where column_id not in (select column_id from #nonclus_keys)
        open mycursor;
        fetch next from mycursor into @column_id, @column_name, @col_descending;
        WHILE @@FETCH_STATUS = 0
        begin
            select @colstr = ISNULL(@colstr, N'') + @column_name + CASE WHEN @col_descending = 1 THEN '(-)' ELSE N'' END + N', ';
            fetch next from mycursor into @column_id, @column_name, @col_descending;
        end
        close mycursor;
        deallocate mycursor;    

        select @ColsInLeaf = substring(@colstr, 1, LEN(@colstr) -1);
        select @colstr = ''

    end
    -- Cleanup
    drop table #clus_keys;
    drop table #nonclus_keys;

END;
GO

exec sys.sp_MS_marksystemobject 'sp_SQLskills_ExposeColsInIndexLevels'
go

sp_SQLskills_ExposeColsInIndexLevels

这段代码用于返回tree/leaf结点的定义。
Step 2: Setup the replacement procedure for sp_helpindex -> sp_SQLskills_helpindex

/*============================================================================
  File:     sp_SQLskills_helpindex.sql

  Summary:  So, what are the included columns?! Do you have a filter?
            This is a MODIFIED sp_helpindex script that includes:
               - Index IDs
               - INCLUDEd columns
               - Filtered index columns
               - Leaf/tree details for rowstore indexes
               - Columns defined for columnstore indexes
            Additional details:
               - whether or not the index is disabled
               - Index usage stats

  Date:     February 2016

  Version:  Works on 2008R2 - 2016 (requires: sp_SQLskills_ExposeColsInIndexLevels)
------------------------------------------------------------------------------
  Written by Kimberly L. Tripp, SYSolutions, Inc.

  For more scripts and sample code, check out
    http://www.SQLskills.com

  This script is intended only as a supplement to demos and lectures
  given by SQLskills instructors.  

  THIS CODE AND INFORMATION ARE PROVIDED "AS IS" WITHOUT WARRANTY OF
  ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED
  TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
  PARTICULAR PURPOSE.
============================================================================*/

USE [master];
GO

IF OBJECTPROPERTY(OBJECT_ID(N'sp_SQLskills_helpindex')
        , N'IsProcedure') = 1
    DROP PROCEDURE [dbo].[sp_SQLskills_helpindex];
GO

SET ANSI_NULLS ON;
SET QUOTED_IDENTIFIER ON;
GO

CREATE PROCEDURE [dbo].[sp_SQLskills_helpindex]
    @objname nvarchar(776)        -- the table to check for indexes
as

--     June 2016: Support for clustered columnstore as well as removing
--                errors around other index types (hekaton, XML, spatial, etc.)
--September 2013: Correct the output for columnstore indexes.
-- November 2010: Added a column to show if an index is disabled.
--      May 2010: Added tree/leaf columns to the output - this requires the
--                stored procedure: sp_SQLskills_ExposeColsInIndexLevels
--    March 2010: Added index_id to the output (ordered by index_id as well)
--   August 2008: Fixed a bug (missing begin/end block) AND I found
--                a few other issues that people hadn't noticed (yikes!)!
--    April 2008: Updated to add included columns to the output. 

-- See my blog for updates and/or additional information
-- http://www.SQLskills.com/blogs/Kimberly (Kimberly L. Tripp)

    set nocount on

    declare @objid int,                -- the object id of the table
            @indid smallint,        -- the index id of an index
            @type tinyint,            -- the index type
            @groupid int,              -- the filegroup id of an index
            @indname sysname,
            @groupname sysname,
            @status int,
            @keys nvarchar(2126),    --Length (16*max_identifierLength)+(15*2)+(16*3)
            @inc_columns nvarchar(max),
            @inc_Count smallint,
            @loop_inc_Count smallint,
            @dbname    sysname,
            @ignore_dup_key    bit,
            @is_unique bit,
            @is_hypothetical bit,
            @is_primary_key    bit,
            @is_unique_key bit,
            @is_disabled bit,
            @auto_created bit,
            @no_recompute bit,
            @filter_definition nvarchar(max),
            @ColsInTree nvarchar(2126),
            @ColsInLeaf nvarchar(max),
            @ExecStr nvarchar(max)

    -- Check to see that the object names are local to the current database.
    select @dbname = parsename(@objname,3)
    if @dbname is null
        select @dbname = db_name()
    else if @dbname <> db_name()
        begin
            raiserror(15250,-1,-1)
            return (1)
        end

    -- Check to see the the table exists and initialize @objid.
    select @objid = object_id(@objname)
    if @objid is NULL
    begin
        raiserror(15009,-1,-1,@objname,@dbname)
        return (1)
    end

    -- OPEN CURSOR OVER INDEXES (skip stats: bug shiloh_51196)
    declare ms_crs_ind cursor local static for
        select i.index_id, i.[type], i.data_space_id, QUOTENAME(i.name, N']') AS name,
            i.ignore_dup_key, i.is_unique, i.is_hypothetical, i.is_primary_key, i.is_unique_constraint,
            s.auto_created, s.no_recompute, i.filter_definition, i.is_disabled
        from sys.indexes as i
            join sys.stats as s
                on i.object_id = s.object_id
                    and i.index_id = s.stats_id
        where i.object_id = @objid
    open ms_crs_ind
    fetch ms_crs_ind into @indid, @type, @groupid, @indname, @ignore_dup_key, @is_unique, @is_hypothetical,
            @is_primary_key, @is_unique_key, @auto_created, @no_recompute, @filter_definition, @is_disabled

    -- IF NO INDEX, QUIT
    if @@fetch_status < 0
    begin
        deallocate ms_crs_ind
        raiserror(15472,-1,-1,@objname) -- Object does not have any indexes.
        return (0)
    end

    -- create temp tables
    CREATE TABLE #spindtab
    (
        objname                nvarchar(776), -- for exec sp_MSforeachtable identifying indexes on which table(Add By Uest)
        index_name            sysname    collate database_default NOT NULL,
        index_id            int,
        [type]                tinyint,
        ignore_dup_key        bit,
        is_unique            bit,
        is_hypothetical        bit,
        is_primary_key        bit,
        is_unique_key        bit,
        is_disabled         bit,
        auto_created        bit,
        no_recompute        bit,
        groupname            sysname collate database_default NULL,
        index_keys            nvarchar(2126)    collate database_default NULL, -- see @keys above for length descr
        filter_definition    nvarchar(max),
        inc_Count            smallint,
        inc_columns            nvarchar(max),
        cols_in_tree        nvarchar(2126),
        cols_in_leaf        nvarchar(max)
    )

    CREATE TABLE #IncludedColumns
    (    RowNumber    smallint,
        [Name]    nvarchar(128)
    )

    -- Now check out each index, figure out its type and keys and
    --    save the info in a temporary table that we'll print out at the end.
    while @@fetch_status >= 0
    begin
        -- First we'll figure out what the keys are.
        declare @i int, @thiskey nvarchar(131) -- 128+3

        select @keys = QUOTENAME(index_col(@objname, @indid, 1), N']'), @i = 2
        if (indexkey_property(@objid, @indid, 1, 'isdescending') = 1)
            select @keys = @keys  + '(-)'

        select @thiskey = QUOTENAME(index_col(@objname, @indid, @i), N']')
        if ((@thiskey is not null) and (indexkey_property(@objid, @indid, @i, 'isdescending') = 1))
            select @thiskey = @thiskey + '(-)'

        while (@thiskey is not null )
        begin
            select @keys = @keys + ', ' + @thiskey, @i = @i + 1
            select @thiskey = QUOTENAME(index_col(@objname, @indid, @i), N']')
            if ((@thiskey is not null) and (indexkey_property(@objid, @indid, @i, 'isdescending') = 1))
                select @thiskey = @thiskey + '(-)'
        end

        -- Second, we'll figure out what the included columns are.
        select @inc_columns = NULL

        SELECT @inc_Count = count(*)
        FROM sys.tables AS tbl
        INNER JOIN sys.indexes AS si
            ON (si.index_id > 0
                and si.is_hypothetical = 0)
                AND (si.object_id=tbl.object_id)
        INNER JOIN sys.index_columns AS ic
            ON (ic.column_id > 0
                and (ic.key_ordinal > 0 or ic.partition_ordinal = 0 or ic.is_included_column != 0))
                AND (ic.index_id=CAST(si.index_id AS int) AND ic.object_id=si.object_id)
        INNER JOIN sys.columns AS clmns
            ON clmns.object_id = ic.object_id
            and clmns.column_id = ic.column_id
        WHERE ic.is_included_column = 1 and
            (si.index_id = @indid) and
            (tbl.object_id= @objid)

        IF @inc_Count > 0
        BEGIN
            DELETE FROM #IncludedColumns
            INSERT #IncludedColumns
                SELECT ROW_NUMBER() OVER (ORDER BY clmns.column_id)
                , clmns.name
                FROM sys.tables AS tbl
                INNER JOIN sys.indexes AS si
                    ON (si.index_id > 0
                        AND si.is_hypothetical = 0)
                        AND (si.object_id=tbl.object_id)
                INNER JOIN sys.index_columns AS ic
                    ON (ic.column_id > 0
                        AND (ic.key_ordinal > 0 OR ic.partition_ordinal = 0 OR ic.is_included_column != 0))
                        AND (ic.index_id=CAST(si.index_id AS int) AND ic.object_id=si.object_id)
                INNER JOIN sys.columns AS clmns
                    ON clmns.object_id = ic.object_id
                    AND clmns.column_id = ic.column_id
                WHERE ic.is_included_column = 1 AND
                    (si.index_id = @indid) AND
                    (tbl.object_id= @objid)

            SELECT @inc_columns = QUOTENAME([Name], N']')
            FROM #IncludedColumns
            WHERE RowNumber = 1

            SET @loop_inc_Count = 1

            WHILE @loop_inc_Count < @inc_Count
            BEGIN
                SELECT @inc_columns = @inc_columns + ', ' + QUOTENAME([Name], N']')
                    FROM #IncludedColumns WHERE RowNumber = @loop_inc_Count + 1
                SET @loop_inc_Count = @loop_inc_Count + 1
            END
        END

        SELECT @groupname = null

        SELECT @groupname = name
        FROM sys.data_spaces
        WHERE data_space_id = @groupid

        -- Get the column list for the tree and leaf level, for all nonclustered indexes IF
        -- the table has a clustered index

        -- Clustered index is non-unique
        IF @indid = 1 AND
                (SELECT is_unique
                    FROM sys.indexes
                    WHERE index_id = 1
                        AND object_id = @objid) = 0
            SELECT @ColsInTree = @keys + N', UNIQUIFIER', @ColsInLeaf = N'All columns "included" - the leaf level IS the data row, plus the UNIQUIFIER'

        -- Clustered index AND is unique
        IF @indid = 1 AND (SELECT is_unique FROM sys.indexes WHERE index_id = 1 AND object_id = @objid) = 1
            SELECT @ColsInTree = @keys, @ColsInLeaf = N'All columns "included" - the leaf level IS the data row.'

        -- Only run this for nonclustered indexes
        IF @indid > 1
            EXEC [sp_SQLskills_ExposeColsInIndexLevels] @objid, @indid, @ColsInTree OUTPUT, @ColsInLeaf OUTPUT

        -- Nonclustered, non-unique index with non-unique clustered ROWSTORE (type = 1) index
        IF @indid > 1 AND @is_unique = 0
                AND (SELECT is_unique
                    FROM sys.indexes
                    WHERE index_id = 1 AND type = 1
                        AND object_id = @objid) = 0
            SELECT @ColsInTree = @ColsInTree + N', UNIQUIFIER', @ColsInLeaf = @ColsInLeaf + N', UNIQUIFIER'

        -- Nonclustered, unique index with non-unique clustered ROWSTORE (type = 1) index
        IF @indid > 1 AND @is_unique = 1
            AND (SELECT is_unique
                    FROM sys.indexes
                    WHERE index_id = 1 AND type = 1
                        AND object_id = @objid) = 0
            SELECT @ColsInLeaf = @ColsInLeaf + N', UNIQUIFIER'

        -- Nonclustered rowstore on a heap
        IF (@indid > 1 AND @type = 2)
                AND (SELECT COUNT(*)
                     FROM sys.indexes
                     WHERE index_id = 1
                        AND object_id = @objid) = 0 -- table is a HEAP
        BEGIN
            IF (@is_unique_key = 0)
                SELECT @ColsInTree = @keys + N', RID'
                    , @ColsInLeaf = @keys + N', RID' + CASE WHEN @inc_columns IS NOT NULL THEN N', ' + @inc_columns ELSE N'' END

            IF (@is_unique_key = 1)
                SELECT @ColsInTree = @keys
                    , @ColsInLeaf = @keys + N', RID' + CASE WHEN @inc_columns IS NOT NULL THEN N', ' + @inc_columns ELSE N'' END
        END

        -- INSERT ROW FOR INDEX

        insert into #spindtab values (@objname, @indname, @indid, @type, @ignore_dup_key, @is_unique, @is_hypothetical,
            @is_primary_key, @is_unique_key, @is_disabled, @auto_created, @no_recompute, @groupname, @keys, @filter_definition, @inc_Count, @inc_columns, @ColsInTree, @ColsInLeaf)

        -- Next index
        fetch ms_crs_ind into @indid, @type, @groupid, @indname, @ignore_dup_key, @is_unique, @is_hypothetical,
            @is_primary_key, @is_unique_key, @auto_created, @no_recompute, @filter_definition, @is_disabled
    end
    deallocate ms_crs_ind

    -- DISPLAY THE RESULTS

-- Query by version
    IF CONVERT(smallint, SUBSTRING(CONVERT(varchar(50), SERVERPROPERTY('ProductVersion')), 1, 2)) < 16

        select @ExecStr = 

            N'select '
                + N'''table_name'' = objname,              '
                + N'''index_id'' = index_id,              '
                + N'''is_disabled'' = is_disabled,        '
                + N'''index_name'' = index_name,          '
                + N'''index_description'' =               '
                    + N' convert(varchar(210), ' --bits 16 off, 1, 2, 16777216 on, located on group   '
                    + N'   case when index_id = 1 and type = 1 then ''clustered''                   '
                    + N'       when index_id = 1 and type = 5 then ''clustered, columnstore''       '
                    + N'       when index_id > 1 and type = 2 then ''nonclustered''    '
                    + N'       when index_id > 1 and type = 6 then ''nonclustered, columnstore''    '
                    + N'       when index_id > 1 and type = 7 then ''nonclustered, HASH''    '
                    + N'   else ''new index type'' end                                              '
                    + N'   + case when ignore_dup_key <>0 then '', ignore duplicate keys'' else '''' end '
                    + N'   + case when is_unique=1 then '', unique'' else '''' end                       '
                    + N'   + case when is_hypothetical <>0 then '', hypothetical'' else '''' end         '
                    + N'   + case when is_primary_key <>0 then '', primary key'' else '''' end           '
                    + N'   + case when is_unique_key <>0 then '', unique key'' else '''' end             '
                    + N'   + case when auto_created <>0 then '', auto create'' else '''' end             '
                    + N'   + case when no_recompute <>0 then '', stats no recompute'' else '''' end      '
                    + N'   + case when groupname IS NOT NULL then '' located on '' + groupname else '''' end),  '
                + N'''index_keys'' =
                      case when type IN (5, 6) then ''n/a, see columns_in_leaf for details''
                      else index_keys end,
                   ''included_columns'' =
                      case when type IN (5, 6) then ''n/a, columnstore index''
                           when type = 7 then ''n/a, HASH''
                      else inc_columns end,
                   ''filter_definition'' =
                      case when type IN (5, 6) then ''n/a, columnstore index''
                           when type = 7 then ''n/a, HASH''
                      else filter_definition end,
                   ''columns_in_tree'' =
                      case when type IN (5, 6) then ''n/a, columnstore index''
                           when type = 7 then ''n/a, HASH''
                      else cols_in_tree end,
                   ''columns_in_leaf'' =
                      case when type IN (5, 6) then ''Columns with columnstore index: '' + cols_in_leaf
                            when type = 7 then ''n/a, HASH''
                      else cols_in_leaf end 

            from #spindtab
            order by index_id '

    IF CONVERT(smallint, SUBSTRING(CONVERT(varchar(50), SERVERPROPERTY('ProductVersion')), 1, 2)) >= 16

        select @ExecStr = 

            N'select '
                + N'''table_name'' = objname,              '
                + N'''index_id'' = index_id,              '
                + N'''is_disabled'' = is_disabled,        '
                + N'''index_name'' = index_name,          '
                + N'''index_description'' =               '
                    + N' convert(varchar(210), ' --bits 16 off, 1, 2, 16777216 on, located on group   '
                    + N'   case when index_id = 1 and type = 1 then ''clustered''                   '
                    + N'       when index_id = 1 and type = 5 then ''clustered, columnstore''       '
                    + N'       when index_id > 1 and type = 2 then ''nonclustered''    '
                    + N'       when index_id > 1 and type = 6 then ''nonclustered, columnstore''    '
                    + N'       when index_id > 1 and type = 7 then ''nonclustered, HASH''    '
                    + N'   else ''new index type'' end                                              '
                    + N'   + case when ignore_dup_key <>0 then '', ignore duplicate keys'' else '''' end '
                    + N'   + case when is_unique=1 then '', unique'' else '''' end                       '
                    + N'   + case when is_hypothetical <>0 then '', hypothetical'' else '''' end         '
                    + N'   + case when is_primary_key <>0 then '', primary key'' else '''' end           '
                    + N'   + case when is_unique_key <>0 then '', unique key'' else '''' end             '
                    + N'   + case when auto_created <>0 then '', auto create'' else '''' end             '
                    + N'   + case when no_recompute <>0 then '', stats no recompute'' else '''' end      '
                    + N'   + case when memory_optimized = 1 then '' located in MEMORY '' else '''' end   '
                    + N'   + case when groupname IS NOT NULL AND
                                    (memory_optimized = 0 OR memory_optimized IS NULL)
                                    then '' located on '' + groupname else '''' end),  '
                + N'''index_keys'' =
                      case when type IN (5, 6) then ''n/a, see columns_in_leaf for details''
                      else index_keys end,
                   ''included_columns'' =
                      case when type IN (5, 6) then ''n/a, columnstore index''
                           when type = 7 then ''n/a, HASH''
                      else inc_columns end,
                   ''filter_definition'' =
                      case when type IN (5, 6) then ''n/a, columnstore index''
                           when type = 7 then ''n/a, HASH''
                      else filter_definition end,
                   ''columns_in_tree'' =
                      case when type IN (5, 6) then ''n/a, columnstore index''
                           when type = 7 then ''n/a, HASH''
                      else cols_in_tree end,
                   ''columns_in_leaf'' =
                      case when type IN (5, 6) then ''Columns with columnstore index: '' + cols_in_leaf
                            when type = 7 then ''n/a, HASH''
                      else cols_in_leaf end 

            from #spindtab
            order by index_id '

    --SELECT (@ExecStr)
    EXEC (@ExecStr)

    return (0) -- sp_SQLskills_helpindex
go

exec [sys].[sp_MS_marksystemobject] 'sp_SQLskills_helpindex'
go

sp_SQLskills_helpindex

返回结果添加table_name字段，方便 exec sp_MSforeachtable 得到库下所有表格上的索引信息
二、sp_helpindex VS sp_SQLskills_helpindex
首先得到测试数据

USE Test
GO
SELECT *
INTO Test.dbo.SalesOrderDetail
FROM AdventureWorks2008R2.Sales.SalesOrderDetail
GO
CREATE UNIQUE CLUSTERED INDEX CIX_SalesOrderDetailID ON dbo.SalesOrderDetail(SalesOrderDetailID)
CREATE INDEX IX_SalesOrderID1 ON dbo.SalesOrderDetail(SalesOrderID,rowguid,SalesOrderDetailID) INCLUDE(LineTotal)
CREATE INDEX IX_SalesOrderID2 ON dbo.SalesOrderDetail(SalesOrderID,rowguid) INCLUDE(LineTotal)
CREATE INDEX IX_SalesOrderID3 ON dbo.SalesOrderDetail(SalesOrderID,rowguid) INCLUDE(SalesOrderDetailID,LineTotal)
CREATE UNIQUE INDEX IX_SalesOrderID4 ON dbo.SalesOrderDetail(SalesOrderID,rowguid) INCLUDE(SalesOrderDetailID,LineTotal)
GO
-- Clean up
--DROP TABLE Test.dbo.SalesOrderDetail

Test Data

对比sp_helpindex和sp_SQLskills_helpindex的返回结果

USE Test
GO
sp_helpindex 'dbo.SalesOrderDetail'
GO
sp_SQLskills_helpindex 'dbo.SalesOrderDetail'
GO

helpindex

从返回的结果来看sp_helpindex的结果不够友好，只知道索引名称、描述、键值。而sp_SQLskills_helpindex返回有表名、索引ID、是否禁用、索引名称、描述、键值、包含列、过滤条件、tree/leaf定义。
从sp_SQLskills_helpindex结果可以得知IX_SalesOrderID1、IX_SalesOrderID2、IX_SalesOrderID3具有相同的tree/leaf定义，后面的两个索引重复。
三、如何得到重复索引

if OBJECT_ID('tempdb..#FindDupes') is not null
    DROP TABLE #FindDupes;
GO

CREATE TABLE #FindDupes
(
 table_name            varchar(776),
 index_id           int,
 is_disabled        bit,
 index_name         sysname,
 index_description  varchar(210),
 index_keys         nvarchar(2126),
 included_columns   nvarchar(max),
 filter_definition  nvarchar(max),
 columns_in_tree    nvarchar(2126),
 columns_in_leaf    nvarchar(max)
);
GO

--INSERT INTO #FindDupes EXEC sp_SQLskills_helpindex 'dbo.SalesOrderDetail';
EXEC sp_MSforeachtable 'insert into #FindDupes exec sp_SQLskills_helpindex ''?'''
GO

-- find duplicate indexes
SELECT t1.index_id, COUNT(*) AS 'Duplicate Indexes w/Lower Index_ID',
        N'DROP INDEX '
            + t1.table_name
            + N'.'
            + t1.index_name AS 'Drop Index Statement'
FROM #FindDupes AS t1
    INNER JOIN #FindDupes AS t2
        ON t1.table_name=t2.table_name
            AND t1.columns_in_tree = t2.columns_in_tree
            AND t1.columns_in_leaf = t2.columns_in_leaf
            AND ISNULL(t1.filter_definition, 1) = ISNULL(t2.filter_definition, 1)
            AND PATINDEX('%unique%', t1.index_description) = PATINDEX('%unique%', t2.index_description)
            AND t1.index_id > t2.index_id
GROUP BY t1.index_id, N'DROP INDEX ' + t1.table_name
                    + N'.' + t1.index_name;
GO

Find Duplicate Indexes

具体数据表直接执行，使用sp_MSforeachtable返回整个数据库中各数据表的索引信息

重点关注大表，频繁写入的数据表，检查是否有重复索引。