SQL Fool Adventures in SQL Tuning – a blog for the rest of us

Create Procedure dbo.dba_viewPageData_sp
 
        /* Declare Parameters */
          @databaseName varchar(128)
        , @tableName    varchar(128)    = Null -- database.schema.tableName
        , @indexName    varchar(128)    = Null
        , @fileNumber   int             = Null
        , @pageNumber   int             = Null
        , @printOption  int             = 3    -- 0, 1, 2, or 3
        , @pageType     char(4)         = 'Leaf' -- Leaf, Root, or IAM
 
As
/*********************************************************************************
    Name:       dba_viewPageData_sp
 
    Author:     Michelle Ufford
 
    Purpose:    Retrieves page data for the specified table/page.
 
    Notes:      Can pass either the table name or the pageID, but must pass one, or
                you'll end up with no results. 
                If the table name is passed, it will return the first page.
 
        @tableName must be '<databaseName>.<schemaName>.<tableName>' in order to
            function correctly for cross-database joins.  
 
        @printOption can be one of following values:
            0 - print just the page header
            1 - page header plus per-row hex dumps and a dump of the page slot array
            2 - page header plus whole page hex dump
            3 - page header plus detailed per-row interpretation
 
        Page Options borrowed from: 
        https://blogs.msdn.com/sqlserverstorageengine/archive/2006/06/10/625659.aspx
 
        @pageType must be one of the following values:
            Leaf - returns the first page of the leaf level of your index or heap
            Root - returns the root page of your index
            IAM - returns the index allocation map chain for your index or heap
 
        Conversions borrowed from:
        http://sqlskills.com/blogs/paul/post/Inside-The-Storage-Engine-
        sp_AllocationMetadata-putting-undocumented-system-catalog-views-to-work.aspx
 
    Called by:  DBA
 
    Date        User    Description
    ----------------------------------------------------------------------------
    2009-05-06  MFU     Initial release for public consumption
*********************************************************************************
    Exec dbo.dba_viewPageData_sp
          @databaseName = 'AdventureWorks'
        , @tableName    = 'AdventureWorks.Sales.SalesOrderDetail'
        , @indexName    = 'IX_SalesOrderDetail_ProductID'
        --, @fileNumber   = 1
        --, @pageNumber   = 38208
        , @printOption  = 3
        , @pageType     = 'Root';
*********************************************************************************/
 
Set NoCount On;
Set XACT_Abort On;
Set Ansi_Padding On;
Set Ansi_Warnings On;
Set ArithAbort On;
Set Concat_Null_Yields_Null On;
Set Numeric_RoundAbort Off;
 
Begin
 
    Declare @fileID         int
        , @pageID           int
        , @sqlStatement     nvarchar(1200)
        , @sqlParameters    nvarchar(255)
        , @errorMessage     varchar(100);
 
    Begin Try
 
        If @fileNumber Is Null And @pageNumber Is Null And @tableName Is Null
        Begin
            Set @errorMessage = 'You must provide either a file/page number, or a table name!';
            RaisError(@errorMessage, 16, 1);
        End;
 
        If @pageType Not In ('Leaf', 'Root', 'IAM')
        Begin
            Set @errorMessage = 'You have entered an invalid page type; valid options are "Leaf", "Root", or "IAM"';
            RaisError(@errorMessage, 16, 1);
        End;
 
        If @fileNumber Is Null Or @pageNumber Is Null
        Begin
 
            Set @sqlStatement = 
            Case When @pageType = 'Leaf' Then
                'Select Top 1 @p_fileID = Convert (varchar(6), Convert (int, 
                    SubString (au.first_page, 6, 1) +
                    SubString (au.first_page, 5, 1)))
                , @p_pageID = Convert (varchar(20), Convert (int, 
                     SubString (au.first_page, 4, 1) +
                     SubString (au.first_page, 3, 1) +
                     SubString (au.first_page, 2, 1) +
                     SubString (au.first_page, 1, 1)))'
            When @pageType = 'Root' Then
                'Select Top 1 @p_fileID = Convert (varchar(6), Convert (int, 
                    SubString (au.root_page, 6, 1) +
                    SubString (au.root_page, 5, 1)))
                , @p_pageID = Convert (varchar(20), Convert (int, 
                     SubString (au.root_page, 4, 1) +
                     SubString (au.root_page, 3, 1) +
                     SubString (au.root_page, 2, 1) +
                     SubString (au.root_page, 1, 1)))'
            When @pageType = 'IAM' Then
                'Select Top 1 @p_fileID = Convert (varchar(6), Convert (int, 
                    SubString (au.first_iam_page, 6, 1) +
                    SubString (au.first_iam_page, 5, 1)))
                , @p_pageID = Convert (varchar(20), Convert (int, 
                     SubString (au.first_iam_page, 4, 1) +
                     SubString (au.first_iam_page, 3, 1) +
                     SubString (au.first_iam_page, 2, 1) +
                     SubString (au.first_iam_page, 1, 1)))'
            End + 
            'From ' + QuoteName(ParseName(@databaseName, 1)) + '.sys.indexes AS i
            Join ' + QuoteName(ParseName(@databaseName, 1)) + '.sys.partitions AS p
                On i.[object_id] = p.[object_id]
                And i.index_id = p.index_id
            Join ' + QuoteName(ParseName(@databaseName, 1)) + '.sys.system_internals_allocation_units AS au
                On p.hobt_id = au.container_id
            Where p.[object_id] = Object_ID(@p_tableName)
                And au.first_page > 0x000000000000 ' 
                + Case When @indexName Is Null 
                    Then ';' 
                    Else 'And i.name = @p_indexName;' End;
 
            Set @sqlParameters = '@p_tableName varchar(128)
                                , @p_indexName varchar(128)
                                , @p_fileID int OUTPUT
                                , @p_pageID int OUTPUT';
 
            Execute sp_executeSQL @sqlStatement
                        , @sqlParameters
                        , @p_tableName = @tableName
                        , @p_indexName = @indexName
                        , @p_fileID = @fileID OUTPUT
                        , @p_pageID = @pageID OUTPUT;
 
            End
            Else
            Begin
                Select @fileID = @fileNumber
                    , @pageID = @pageNumber;
            End;
 
        DBCC TraceOn (3604);
        DBCC Page (@databaseName, @fileID, @pageID, @printOption);
        DBCC TraceOff (3604);
 
    End Try
    Begin Catch
 
        Print @errorMessage;
 
    End Catch;
 
    Set NoCount Off;
    Return 0;
End
Go

    Exec dbo.dba_viewPageData_sp
          @databaseName = 'AdventureWorks'
        , @tableName    = 'AdventureWorks.Sales.SalesOrderDetail'
        , @indexName    = 'IX_SalesOrderDetail_ProductID';

DBCC execution completed. If DBCC printed error messages, contact your system administrator.
 
PAGE: (1:11000)
 
BUFFER:
 
BUF @0x0391F140
 
bpage = 0x0C0C0000                   bhash = 0x00000000                   bpageno = (1:11000)
bdbid = 7                            breferences = 0                      bUse1 = 35177
bstat = 0x1c00009                    blog = 0x21212159                    bnext = 0x00000000