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

8Jun/1013

Check VLF Counts

Today I stumbled across a database with 87,302 VLF's. Yes, that's right... 87 THOUSAND. Most of our databases have a few dozen VLF's, but this was an old database that had grown to 1.5 TB and had the default autogrowth settings left in tact. How did we discover this? During a routine reboot of the server, this database took 30 minutes to recover, but there were no error messages or status messages in the log.

Now, this blog post is not about VLF's or why you should keep the number of VLF's to a small, manageable number -- although I hear under 50 is a good rule of thumb. No, the purpose of this blog post is to share a little script I wrote to check the number of VLF's each database uses:

CREATE TABLE #stage(
    FileID      INT
  , FileSize    BIGINT
  , StartOffset BIGINT
  , FSeqNo      BIGINT
  , [Status]    BIGINT
  , Parity      BIGINT
  , CreateLSN   NUMERIC(38)
);
 
CREATE TABLE #results(
    Database_Name   sysname
  , VLF_count       INT 
);
 
EXEC sp_msforeachdb N'Use ?; 
            Insert Into #stage 
            Exec sp_executeSQL N''DBCC LogInfo(?)''; 
 
            Insert Into #results 
            Select DB_Name(), Count(*) 
            From #stage; 
 
            Truncate Table #stage;'
 
SELECT * 
FROM #results
ORDER BY VLF_count DESC;
 
DROP TABLE #stage;
DROP TABLE #results;

This script is low-impact and is safe to run on large, production databases during business hours. However, just be aware that it's using some undocumented commands.

For more information on VLF's, check out these excellent articles:

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4Jun/103

Index Interrogation for SQL Server 2008

I had previously posted an index interrogation script for SQL Server 2005. I've updated that script for 2008; namely, it includes filtered index definitions. For anyone interested:

DECLARE @objectID INT = OBJECT_ID('Sales.SalesOrderHeader');
 
WITH indexCTE(partition_scheme_name
            , partition_function_name
            , data_space_id)
AS (
    SELECT sps.name
        , spf.name
        , sps.data_space_id
    FROM sys.partition_schemes AS sps
    Join sys.partition_functions AS spf
        ON sps.function_id = spf.function_id
)
 
SELECT st.name AS 'table_name'
    , IsNull(ix.name, '') AS 'index_name'
    , ix.OBJECT_ID
    , ix.index_id
	, CAST(
        CASE WHEN ix.index_id = 1 
                THEN 'clustered' 
            WHEN ix.index_id =0
                THEN 'heap'
            ELSE 'nonclustered' END
		+ CASE WHEN ix.ignore_dup_key <> 0 
            THEN ', ignore duplicate keys' 
                ELSE '' END
		+ CASE WHEN ix.is_unique <> 0 
            THEN ', unique' 
                ELSE '' END
		+ CASE WHEN ix.is_primary_key <> 0 
            THEN ', primary key' ELSE '' END AS VARCHAR(210)
        ) AS 'index_description'
    , IsNull(REPLACE( REPLACE( REPLACE(
        (   
            SELECT c.name AS 'columnName'
            FROM sys.index_columns AS sic
            Join sys.columns AS c 
                ON c.column_id = sic.column_id 
                And c.OBJECT_ID = sic.OBJECT_ID
            WHERE sic.OBJECT_ID = ix.OBJECT_ID
                And sic.index_id = ix.index_id
                And is_included_column = 0
            ORDER BY sic.index_column_id
            FOR XML Raw)
            , '"/><row columnName="', ', ')
            , '<row columnName="', '')
            , '"/>', ''), '')
        AS 'indexed_columns'
    , IsNull(REPLACE( REPLACE( REPLACE(
        (   
            SELECT c.name AS 'columnName'
            FROM sys.index_columns AS sic
            Join sys.columns AS c 
                ON c.column_id = sic.column_id 
                And c.OBJECT_ID = sic.OBJECT_ID
            WHERE sic.OBJECT_ID = ix.OBJECT_ID
                And sic.index_id = ix.index_id
                And is_included_column = 1
            ORDER BY sic.index_column_id
            FOR XML Raw)
            , '"/><row columnName="', ', ')
            , '<row columnName="', '')
            , '"/>', ''), '')
        AS 'included_columns'
    , ix.filter_definition
    , IsNull(cte.partition_scheme_name, '') AS 'partition_scheme_name'
    , COUNT(partition_number) AS 'partition_count'
    , SUM(ROWS) AS 'row_count'
FROM sys.indexes AS ix
Join sys.partitions AS sp
    ON ix.OBJECT_ID = sp.OBJECT_ID
    And ix.index_id = sp.index_id
Join sys.tables AS st
    ON ix.OBJECT_ID = st.OBJECT_ID
LEFT Join indexCTE AS cte
    ON ix.data_space_id = cte.data_space_id
WHERE ix.OBJECT_ID = IsNull(@objectID, ix.OBJECT_ID)
GROUP BY st.name
    , IsNull(ix.name, '')
    , ix.OBJECT_ID
    , ix.index_id
	, CAST(
        CASE WHEN ix.index_id = 1 
                THEN 'clustered' 
            WHEN ix.index_id =0
                THEN 'heap'
            ELSE 'nonclustered' END
		+ CASE WHEN ix.ignore_dup_key <> 0 
            THEN ', ignore duplicate keys' 
                ELSE '' END
		+ CASE WHEN ix.is_unique <> 0 
            THEN ', unique' 
                ELSE '' END
		+ CASE WHEN ix.is_primary_key <> 0 
            THEN ', primary key' ELSE '' END AS VARCHAR(210)
        )
    , ix.filter_definition
    , IsNull(cte.partition_scheme_name, '')
    , IsNull(cte.partition_function_name, '')
ORDER BY table_name
    , index_id;

You may need to create some indexes to see this in AdventureWorks:

CREATE NONCLUSTERED INDEX IX_Sales_SalesOrderHeader_filtered_2005
    ON Sales.SalesOrderHeader(AccountNumber)
    Include (CustomerID, SalesPersonID)
    WHERE OrderDate >= '2005-01-01'
        And OrderDate < '2006-01-01';
table_name           index_name                               object_id   index_id    index_description                   indexed_columns      included_columns               filter_definition                                            partition_scheme_name partition_count row_count
-------------------- ---------------------------------------- ----------- ----------- ----------------------------------- -------------------- ------------------------------ ------------------------------------------------------------ --------------------- --------------- --------------------
SalesOrderHeader     PK_SalesOrderHeader_SalesOrderID         1010102639  1           clustered, unique, primary key      SalesOrderID                                        NULL                                                                               1               31465
SalesOrderHeader     AK_SalesOrderHeader_rowguid              1010102639  2           nonclustered, unique                rowguid                                             NULL                                                                               1               31465
SalesOrderHeader     AK_SalesOrderHeader_SalesOrderNumber     1010102639  3           nonclustered, unique                SalesOrderNumber                                    NULL                                                                               1               31465
SalesOrderHeader     IX_SalesOrderHeader_CustomerID           1010102639  5           nonclustered                        CustomerID                                          NULL                                                                               1               31465
SalesOrderHeader     IX_SalesOrderHeader_SalesPersonID        1010102639  6           nonclustered                        SalesPersonID                                       NULL                                                                               1               31465
SalesOrderHeader     IX_Sales_SalesOrderHeader_filtered_2005  1010102639  13          nonclustered                        AccountNumber        CustomerID, SalesPersonID      ([OrderDate]>='2005-01-01' AND [OrderDate]<'2006-01-01')                           1               1379
Tagged as: , , , , , 3 Comments
22Apr/1039

Index Defrag Script, v4.0

In my blog post, "Index Defrag Script Updates - Beta Testers Needed", I stated "I'll hopefully have the new version online in just a few days." That was dated January 26th. I had every intention of following through with it, too, but something came up:

My daughter, Chloe Lynn, was born on February 10th. She's a happy, healthy baby girl who consumes all of my free time and already has both her parents wrapped around her adorable little finger. So while I apologize for the delay in posting the latest version, I hope you can understand and forgive me. :)

Alrighty, back to SQL stuff! This version of the script has been significantly overhauled from previous versions. Here's a full synopsis of the changes and enhancements:

- There's now a time limit option so you have more control over how long your defrags run. This time limit is checked *before* a defrag is begun, so it's still possible to have a defrag occur after the time limit is exceeded (i.e. a large index).

- I've added a static table for managing the index defrag scans. This way, you can start and stop the defrag process without the need to rescan. This is especially useful for VLDB's or any environment where you're unable to complete the defrags in one operation.

- Just in case you want to perform a rescan, even if there's still indexes left to defrag from your last rescan, there's a parameter to force it.

- There's now an option to sort by page count, range scan count, or fragmentation level. Range scan count is defaulted, as the indexes that have high amounts of range scans will benefit the most from having a defragged index. You can also specify whether you want to sort by ASC or DESC.

- There's now min and max parameters for page counts. This is useful for a) ignoring indexes with less than 1 extent (as recommended by Microsoft) and b) for scheduling index operations by size. For instance, you may want to defrag your small indexes during business hours but leave your big indexes for evening or weekend hours.

- There's now a parameterized option for sorting in TEMPDB. This may reduce execution time and will prevent unnecessary database file size inflation during defrags. NOTE: Make sure you have enough free space in TEMPDB prior to enabling this option.

- I moved the SQL statement output to display before execution so you can see what's currently executing.

- I've added a debug output of the parameters selected. I've added additional validation to the start of the script, so this will help show you if an invalid value was submitted and overwritten.

- I've added new columns to the log table to show what command is being executed and what error, if any, occurred when trying to execute.

- I've added try/catch logic to handle errors during execution; this way, a single error will not prevent the whole script from terminating.

- The script will now force a rebuild for indexes with allow_page_locks = off.

- For those who use partitioning, you can now exclude the right-most populated partition from the defrag operation. This won't be applicable for all partitioning schemes, but for sliding-window scenarios (one of the most common schemes), it'll reduce contention on the partition that's being actively written to.

- I've fixed a bug where tables with LOB indexes may have more than one record returned from sys.dm_db_index_physical_stats.

- For various reasons, I've removed the option to rebuild stats.

Also, if you have a previous version of the script installed, this version will rename those tables, since there have been some changes made to them.

FAQ:

I often receive the same questions about this script, so allow me to answer them here:

"I keep running the script, but my index is still fragmented. Why?"
This is most likely a very small index. Here's what Microsoft has to say:

"In general, fragmentation on small indexes is often not controllable. The pages of small indexes are stored on mixed extents. Mixed extents are shared by up to eight objects, so the fragmentation in a small index might not be reduced after reorganizing or rebuilding the index. For more information about mixed extents, see Understanding Pages and Extents."

"What database should I create it in?" or "Can I create this in the MASTER database?"
It's up to you where you create it. You could technically create it in the MASTER database, but I recommend creating a utility database for your DBA administrative tasks.

"Can I run this againt a SharePoint database?"
I've never tried personally, but I've been told it runs just fine.

"What are the minimum requirements to run this script?" or "Will this run on SQL Server 2000 instances?"
You need to be on SQL Server 2005 SP2 or higher.

Without further ado, here's the script:

/* Scroll down to the see notes, disclaimers, and licensing information */
 
DECLARE @indexDefragLog_rename      VARCHAR(128)
    , @indexDefragExclusion_rename  VARCHAR(128)
    , @indexDefragStatus_rename     VARCHAR(128);
 
SELECT @indexDefragLog_rename       = 'dba_indexDefragLog_obsolete_' + CONVERT(VARCHAR(10), GETDATE(), 112)
    , @indexDefragExclusion_rename  = 'dba_indexDefragExclusion_obsolete_' + CONVERT(VARCHAR(10), GETDATE(), 112)
    , @indexDefragStatus_rename     = 'dba_indexDefragStatus_obsolete_' + CONVERT(VARCHAR(10), GETDATE(), 112);
 
IF Exists(SELECT [OBJECT_ID] FROM sys.tables WHERE [name] = 'dba_indexDefragLog')
    EXECUTE SP_RENAME dba_indexDefragLog, @indexDefragLog_rename;
 
IF Exists(SELECT [OBJECT_ID] FROM sys.tables WHERE [name] = 'dba_indexDefragExclusion')
    EXECUTE SP_RENAME dba_indexDefragExclusion, @indexDefragExclusion_rename;
 
IF Exists(SELECT [OBJECT_ID] FROM sys.tables WHERE [name] = 'dba_indexDefragStatus')
    EXECUTE SP_RENAME dba_indexDefragStatus, @indexDefragStatus_rename;
Go
 
CREATE TABLE dbo.dba_indexDefragLog
(
      indexDefrag_id    INT IDENTITY(1,1)   Not Null
    , databaseID        INT                 Not Null
    , databaseName      NVARCHAR(128)       Not Null
    , objectID          INT                 Not Null
    , objectName        NVARCHAR(128)       Not Null
    , indexID           INT                 Not Null
    , indexName         NVARCHAR(128)       Not Null
    , partitionNumber   SMALLINT            Not Null
    , fragmentation     FLOAT               Not Null
    , page_count        INT                 Not Null
    , dateTimeStart     DATETIME            Not Null
    , dateTimeEnd       DATETIME            Null
    , durationSeconds   INT                 Null
    , sqlStatement      VARCHAR(4000)       Null
    , errorMessage      VARCHAR(1000)       Null
 
    CONSTRAINT PK_indexDefragLog_v40
        PRIMARY KEY CLUSTERED (indexDefrag_id)
);
 
PRINT 'dba_indexDefragLog Table Created';
 
CREATE TABLE dbo.dba_indexDefragExclusion
(
      databaseID        INT                 Not Null
    , databaseName      NVARCHAR(128)       Not Null
    , objectID          INT                 Not Null
    , objectName        NVARCHAR(128)       Not Null
    , indexID           INT                 Not Null
    , indexName         NVARCHAR(128)       Not Null
    , exclusionMask     INT                 Not Null
        /* 1=Sunday, 2=Monday, 4=Tuesday, 8=Wednesday, 16=Thursday, 32=Friday, 64=Saturday */
 
    CONSTRAINT PK_indexDefragExclusion_v40
        PRIMARY KEY CLUSTERED (databaseID, objectID, indexID)
);
 
PRINT 'dba_indexDefragExclusion Table Created';
 
CREATE TABLE dbo.dba_indexDefragStatus
(
      databaseID        INT
    , databaseName      NVARCHAR(128)
    , objectID          INT
    , indexID           INT
    , partitionNumber   SMALLINT
    , fragmentation     FLOAT
    , page_count        INT
    , range_scan_count  BIGINT
    , schemaName        NVARCHAR(128)   Null
    , objectName        NVARCHAR(128)   Null
    , indexName         NVARCHAR(128)   Null
    , scanDate          DATETIME        
    , defragDate        DATETIME        Null
    , printStatus       BIT             DEFAULT(0)
    , exclusionMask     INT             DEFAULT(0)
 
    CONSTRAINT PK_indexDefragStatus_v40
        PRIMARY KEY CLUSTERED(databaseID, objectID, indexID, partitionNumber)
);
 
PRINT 'dba_indexDefragStatus Table Created';
 
IF OBJECTPROPERTY(OBJECT_ID('dbo.dba_indexDefrag_sp'), N'IsProcedure') = 1
BEGIN
    DROP PROCEDURE dbo.dba_indexDefrag_sp;
    PRINT 'Procedure dba_indexDefrag_sp dropped';
END;
Go
 
CREATE PROCEDURE dbo.dba_indexDefrag_sp
 
    /* Declare Parameters */
      @minFragmentation     FLOAT           = 10.0  
        /* in percent, will not defrag if fragmentation less than specified */
    , @rebuildThreshold     FLOAT           = 30.0  
        /* in percent, greater than @rebuildThreshold will result in rebuild instead of reorg */
    , @executeSQL           BIT             = 1     
        /* 1 = execute; 0 = print command only */
    , @defragOrderColumn    NVARCHAR(20)    = 'range_scan_count'
        /* Valid options are: range_scan_count, fragmentation, page_count */
    , @defragSortOrder      NVARCHAR(4)     = 'DESC'
        /* Valid options are: ASC, DESC */
    , @timeLimit            INT             = 720 /* defaulted to 12 hours */
        /* Optional time limitation; expressed in minutes */
    , @DATABASE             VARCHAR(128)    = Null
        /* Option to specify a database name; null will return all */
    , @tableName            VARCHAR(4000)   = Null  -- databaseName.schema.tableName
        /* Option to specify a table name; null will return all */
    , @forceRescan          BIT             = 0
        /* Whether or not to force a rescan of indexes; 1 = force, 0 = use existing scan, if available */
    , @scanMode             VARCHAR(10)     = N'LIMITED'
        /* Options are LIMITED, SAMPLED, and DETAILED */
    , @minPageCount         INT             = 8 
        /*  MS recommends > 1 extent (8 pages) */
    , @maxPageCount         INT             = Null
        /* NULL = no limit */
    , @excludeMaxPartition  BIT             = 0
        /* 1 = exclude right-most populated partition; 0 = do not exclude; see notes for caveats */
    , @onlineRebuild        BIT             = 1     
        /* 1 = online rebuild; 0 = offline rebuild; only in Enterprise */
    , @sortInTempDB         BIT             = 1
        /* 1 = perform sort operation in TempDB; 0 = perform sort operation in the index's database */
    , @maxDopRestriction    TINYINT         = Null
        /* Option to restrict the number of processors for the operation; only in Enterprise */
    , @printCommands        BIT             = 0     
        /* 1 = print commands; 0 = do not print commands */
    , @printFragmentation   BIT             = 0
        /* 1 = print fragmentation prior to defrag; 
           0 = do not print */
    , @defragDelay          CHAR(8)         = '00:00:05'
        /* time to wait between defrag commands */
    , @debugMode            BIT             = 0
        /* display some useful comments to help determine if/where issues occur */
 
AS
/*********************************************************************************
    Name:       dba_indexDefrag_sp
 
    Author:     Michelle Ufford, http://sqlfool.com
 
    Purpose:    Defrags one or more indexes for one or more databases
 
    Notes:
 
    CAUTION: TRANSACTION LOG SIZE SHOULD BE MONITORED CLOSELY WHEN DEFRAGMENTING.
             DO NOT RUN UNATTENDED ON LARGE DATABASES DURING BUSINESS HOURS.
 
      @minFragmentation     defaulted to 10%, will not defrag if fragmentation 
                            is less than that
 
      @rebuildThreshold     defaulted to 30% as recommended by Microsoft in BOL;
                            greater than 30% will result in rebuild instead
 
      @executeSQL           1 = execute the SQL generated by this proc; 
                            0 = print command only
 
      @defragOrderColumn    Defines how to prioritize the order of defrags.  Only
                            used if @executeSQL = 1.  
                            Valid options are: 
                            range_scan_count = count of range and table scans on the
                                               index; in general, this is what benefits 
                                               the most from defragmentation
                            fragmentation    = amount of fragmentation in the index;
                                               the higher the number, the worse it is
                            page_count       = number of pages in the index; affects
                                               how long it takes to defrag an index
 
      @defragSortOrder      The sort order of the ORDER BY clause.
                            Valid options are ASC (ascending) or DESC (descending).
 
      @timeLimit            Optional, limits how much time can be spent performing 
                            index defrags; expressed in minutes.
 
                            NOTE: The time limit is checked BEFORE an index defrag
                                  is begun, thus a long index defrag can exceed the
                                  time limitation.
 
      @database             Optional, specify specific database name to defrag;
                            If not specified, all non-system databases will
                            be defragged.
 
      @tableName            Specify if you only want to defrag indexes for a 
                            specific table, format = databaseName.schema.tableName;
                            if not specified, all tables will be defragged.
 
      @forceRescan          Whether or not to force a rescan of indexes.  If set
                            to 0, a rescan will not occur until all indexes have
                            been defragged.  This can span multiple executions.
                            1 = force a rescan
                            0 = use previous scan, if there are indexes left to defrag
 
      @scanMode             Specifies which scan mode to use to determine
                            fragmentation levels.  Options are:
                            LIMITED - scans the parent level; quickest mode,
                                      recommended for most cases.
                            SAMPLED - samples 1% of all data pages; if less than
                                      10k pages, performs a DETAILED scan.
                            DETAILED - scans all data pages.  Use great care with
                                       this mode, as it can cause performance issues.
 
      @minPageCount         Specifies how many pages must exist in an index in order 
                            to be considered for a defrag.  Defaulted to 8 pages, as 
                            Microsoft recommends only defragging indexes with more 
                            than 1 extent (8 pages).  
 
                            NOTE: The @minPageCount will restrict the indexes that
                            are stored in dba_indexDefragStatus table.
 
      @maxPageCount         Specifies the maximum number of pages that can exist in 
                            an index and still be considered for a defrag.  Useful
                            for scheduling small indexes during business hours and
                            large indexes for non-business hours.
 
                            NOTE: The @maxPageCount will restrict the indexes that
                            are defragged during the current operation; it will not
                            prevent indexes from being stored in the 
                            dba_indexDefragStatus table.  This way, a single scan
                            can support multiple page count thresholds.
 
      @excludeMaxPartition  If an index is partitioned, this option specifies whether
                            to exclude the right-most populated partition.  Typically,
                            this is the partition that is currently being written to in
                            a sliding-window scenario.  Enabling this feature may reduce
                            contention.  This may not be applicable in other types of 
                            partitioning scenarios.  Non-partitioned indexes are 
                            unaffected by this option.
                            1 = exclude right-most populated partition
                            0 = do not exclude
 
      @onlineRebuild        1 = online rebuild; 
                            0 = offline rebuild
 
      @sortInTempDB         Specifies whether to defrag the index in TEMPDB or in the
                            database the index belongs to.  Enabling this option may
                            result in faster defrags and prevent database file size 
                            inflation.
                            1 = perform sort operation in TempDB
                            0 = perform sort operation in the index's database 
 
      @maxDopRestriction    Option to specify a processor limit for index rebuilds
 
      @printCommands        1 = print commands to screen; 
                            0 = do not print commands
 
      @printFragmentation   1 = print fragmentation to screen;
                            0 = do not print fragmentation
 
      @defragDelay          Time to wait between defrag commands; gives the
                            server a little time to catch up 
 
      @debugMode            1 = display debug comments; helps with troubleshooting
                            0 = do not display debug comments
 
    Called by:  SQL Agent Job or DBA
 
    ----------------------------------------------------------------------------
    DISCLAIMER: 
    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 or merchantability and/or fitness for a particular purpose.
    ----------------------------------------------------------------------------
    LICENSE: 
    This index defrag script is free to download and use for personal, educational, 
    and internal corporate purposes, provided that this header is preserved. 
    Redistribution or sale of this index defrag script, in whole or in part, is 
    prohibited without the author's express written consent.
    ----------------------------------------------------------------------------
    Date        Initials	Version Description
    ----------------------------------------------------------------------------
    2007-12-18  MFU         1.0     Initial Release
    2008-10-17  MFU         1.1     Added @defragDelay, CIX_temp_indexDefragList
    2008-11-17  MFU         1.2     Added page_count to log table
                                    , added @printFragmentation option
    2009-03-17  MFU         2.0     Provided support for centralized execution
                                    , consolidated Enterprise & Standard versions
                                    , added @debugMode, @maxDopRestriction
                                    , modified LOB and partition logic  
    2009-06-18  MFU         3.0     Fixed bug in LOB logic, added @scanMode option
                                    , added support for stat rebuilds (@rebuildStats)
                                    , support model and msdb defrag
                                    , added columns to the dba_indexDefragLog table
                                    , modified logging to show "in progress" defrags
                                    , added defrag exclusion list (scheduling)
    2009-08-28  MFU         3.1     Fixed read_only bug for database lists
    2010-04-20  MFU         4.0     Added time limit option
                                    , added static table with rescan logic
                                    , added parameters for page count & SORT_IN_TEMPDB
                                    , added try/catch logic and additional debug options
                                    , added options for defrag prioritization
                                    , fixed bug for indexes with allow_page_lock = off
                                    , added option to exclude right-most partition
                                    , removed @rebuildStats option
                                    , refer to http://sqlfool.com for full release notes
*********************************************************************************
    Example of how to call this script:
 
        Exec dbo.dba_indexDefrag_sp
              @executeSQL           = 1
            , @printCommands        = 1
            , @debugMode            = 1
            , @printFragmentation   = 1
            , @forceRescan          = 1
            , @maxDopRestriction    = 1
            , @minPageCount         = 8
            , @maxPageCount         = Null
            , @minFragmentation     = 1
            , @rebuildThreshold     = 30
            , @defragDelay          = '00:00:05'
            , @defragOrderColumn    = 'page_count'
            , @defragSortOrder      = 'DESC'
            , @excludeMaxPartition  = 1
            , @timeLimit            = Null;
*********************************************************************************/																
SET NOCOUNT ON;
SET XACT_Abort ON;
SET Quoted_Identifier ON;
 
BEGIN
 
    BEGIN Try
 
        /* Just a little validation... */
        IF @minFragmentation IS Null 
            Or @minFragmentation Not Between 0.00 And 100.0
                SET @minFragmentation = 10.0;
 
        IF @rebuildThreshold IS Null
            Or @rebuildThreshold Not Between 0.00 And 100.0
                SET @rebuildThreshold = 30.0;
 
        IF @defragDelay Not Like '00:[0-5][0-9]:[0-5][0-9]'
            SET @defragDelay = '00:00:05';
 
        IF @defragOrderColumn IS Null
            Or @defragOrderColumn Not In ('range_scan_count', 'fragmentation', 'page_count')
                SET @defragOrderColumn = 'range_scan_count';
 
        IF @defragSortOrder IS Null
            Or @defragSortOrder Not In ('ASC', 'DESC')
                SET @defragSortOrder = 'DESC';
 
        IF @scanMode Not In ('LIMITED', 'SAMPLED', 'DETAILED')
            SET @scanMode = 'LIMITED';
 
        IF @debugMode IS Null
            SET @debugMode = 0;
 
        IF @forceRescan IS Null
            SET @forceRescan = 0;
 
        IF @sortInTempDB IS Null
            SET @sortInTempDB = 1;
 
 
        IF @debugMode = 1 RAISERROR('Undusting the cogs and starting up...', 0, 42) WITH NoWait;
 
        /* Declare our variables */
        DECLARE   @objectID                 INT
                , @databaseID               INT
                , @databaseName             NVARCHAR(128)
                , @indexID                  INT
                , @partitionCount           BIGINT
                , @schemaName               NVARCHAR(128)
                , @objectName               NVARCHAR(128)
                , @indexName                NVARCHAR(128)
                , @partitionNumber          SMALLINT
                , @fragmentation            FLOAT
                , @pageCount                INT
                , @sqlCommand               NVARCHAR(4000)
                , @rebuildCommand           NVARCHAR(200)
                , @dateTimeStart            DATETIME
                , @dateTimeEnd              DATETIME
                , @containsLOB              BIT
                , @editionCheck             BIT
                , @debugMessage             NVARCHAR(4000)
                , @updateSQL                NVARCHAR(4000)
                , @partitionSQL             NVARCHAR(4000)
                , @partitionSQL_Param       NVARCHAR(1000)
                , @LOB_SQL                  NVARCHAR(4000)
                , @LOB_SQL_Param            NVARCHAR(1000)
                , @indexDefrag_id           INT
                , @startDateTime            DATETIME
                , @endDateTime              DATETIME
                , @getIndexSQL              NVARCHAR(4000)
                , @getIndexSQL_Param        NVARCHAR(4000)
                , @allowPageLockSQL         NVARCHAR(4000)
                , @allowPageLockSQL_Param   NVARCHAR(4000)
                , @allowPageLocks           INT
                , @excludeMaxPartitionSQL   NVARCHAR(4000);
 
        /* Initialize our variables */
        SELECT @startDateTime = GETDATE()
            , @endDateTime = DATEADD(MINUTE, @timeLimit, GETDATE());
 
        /* Create our temporary tables */
        CREATE TABLE #databaseList
        (
              databaseID        INT
            , databaseName      VARCHAR(128)
            , scanStatus        BIT
        );
 
        CREATE TABLE #processor 
        (
              [INDEX]           INT
            , Name              VARCHAR(128)
            , Internal_Value    INT
            , Character_Value   INT
        );
 
        CREATE TABLE #maxPartitionList
        (
              databaseID        INT
            , objectID          INT
            , indexID           INT
            , maxPartition      INT
        );
 
        IF @debugMode = 1 RAISERROR('Beginning validation...', 0, 42) WITH NoWait;
 
        /* Make sure we're not exceeding the number of processors we have available */
        INSERT INTO #processor
        EXECUTE XP_MSVER 'ProcessorCount';
 
        IF @maxDopRestriction IS Not Null And @maxDopRestriction > (SELECT Internal_Value FROM #processor)
            SELECT @maxDopRestriction = Internal_Value
            FROM #processor;
 
        /* Check our server version; 1804890536 = Enterprise, 610778273 = Enterprise Evaluation, -2117995310 = Developer */
        IF (SELECT SERVERPROPERTY('EditionID')) In (1804890536, 610778273, -2117995310) 
            SET @editionCheck = 1 -- supports online rebuilds
        ELSE
            SET @editionCheck = 0; -- does not support online rebuilds
 
        /* Output the parameters we're working with */
        IF @debugMode = 1 
        BEGIN
 
            SELECT @debugMessage = 'Your selected parameters are... 
            Defrag indexes with fragmentation greater than ' + CAST(@minFragmentation AS VARCHAR(10)) + ';
            Rebuild indexes with fragmentation greater than ' + CAST(@rebuildThreshold AS VARCHAR(10)) + ';
            You' + CASE WHEN @executeSQL = 1 THEN ' DO' ELSE ' DO NOT' END + ' want the commands to be executed automatically; 
            You want to defrag indexes in ' + @defragSortOrder + ' order of the ' + UPPER(@defragOrderColumn) + ' value;
            You have' + CASE WHEN @timeLimit IS Null THEN ' not specified a time limit;' ELSE ' specified a time limit of ' 
                + CAST(@timeLimit AS VARCHAR(10)) END + ' minutes;
            ' + CASE WHEN @DATABASE IS Null THEN 'ALL databases' ELSE 'The ' + @DATABASE + ' database' END + ' will be defragged;
            ' + CASE WHEN @tableName IS Null THEN 'ALL tables' ELSE 'The ' + @tableName + ' table' END + ' will be defragged;
            We' + CASE WHEN Exists(SELECT TOP 1 * FROM dbo.dba_indexDefragStatus WHERE defragDate IS Null)
                And @forceRescan <> 1 THEN ' WILL NOT' ELSE ' WILL' END + ' be rescanning indexes;
            The scan will be performed in ' + @scanMode + ' mode;
            You want to limit defrags to indexes with' + CASE WHEN @maxPageCount IS Null THEN ' more than ' 
                + CAST(@minPageCount AS VARCHAR(10)) ELSE
                ' between ' + CAST(@minPageCount AS VARCHAR(10))
                + ' and ' + CAST(@maxPageCount AS VARCHAR(10)) END + ' pages;
            Indexes will be defragged' + CASE WHEN @editionCheck = 0 Or @onlineRebuild = 0 THEN ' OFFLINE;' ELSE ' ONLINE;' END + '
            Indexes will be sorted in' + CASE WHEN @sortInTempDB = 0 THEN ' the DATABASE' ELSE ' TEMPDB;' END + '
            Defrag operations will utilize ' + CASE WHEN @editionCheck = 0 Or @maxDopRestriction IS Null 
                THEN 'system defaults for processors;' 
                ELSE CAST(@maxDopRestriction AS VARCHAR(2)) + ' processors;' END + '
            You' + CASE WHEN @printCommands = 1 THEN ' DO' ELSE ' DO NOT' END + ' want to print the ALTER INDEX commands; 
            You' + CASE WHEN @printFragmentation = 1 THEN ' DO' ELSE ' DO NOT' END + ' want to output fragmentation levels; 
            You want to wait ' + @defragDelay + ' (hh:mm:ss) between defragging indexes;
            You want to run in' + CASE WHEN @debugMode = 1 THEN ' DEBUG' ELSE ' SILENT' END + ' mode.';
 
            RAISERROR(@debugMessage, 0, 42) WITH NoWait;
 
        END;
 
        IF @debugMode = 1 RAISERROR('Grabbing a list of our databases...', 0, 42) WITH NoWait;
 
        /* Retrieve the list of databases to investigate */
        INSERT INTO #databaseList
        SELECT database_id
            , name
            , 0 -- not scanned yet for fragmentation
        FROM sys.databases
        WHERE name = IsNull(@DATABASE, name)
            And [name] Not In ('master', 'tempdb')-- exclude system databases
            And [STATE] = 0 -- state must be ONLINE
            And is_read_only = 0;  -- cannot be read_only
 
        /* Check to see if we have indexes in need of defrag; otherwise, re-scan the database(s) */
        IF Not Exists(SELECT TOP 1 * FROM dbo.dba_indexDefragStatus WHERE defragDate IS Null)
            Or @forceRescan = 1
        BEGIN
 
            /* Truncate our list of indexes to prepare for a new scan */
            TRUNCATE TABLE dbo.dba_indexDefragStatus;
 
            IF @debugMode = 1 RAISERROR('Looping through our list of databases and checking for fragmentation...', 0, 42) WITH NoWait;
 
            /* Loop through our list of databases */
            WHILE (SELECT COUNT(*) FROM #databaseList WHERE scanStatus = 0) > 0
            BEGIN
 
                SELECT TOP 1 @databaseID = databaseID
                FROM #databaseList
                WHERE scanStatus = 0;
 
                SELECT @debugMessage = '  working on ' + DB_NAME(@databaseID) + '...';
 
                IF @debugMode = 1
                    RAISERROR(@debugMessage, 0, 42) WITH NoWait;
 
               /* Determine which indexes to defrag using our user-defined parameters */
                INSERT INTO dbo.dba_indexDefragStatus
                (
                      databaseID
                    , databaseName
                    , objectID
                    , indexID
                    , partitionNumber
                    , fragmentation
                    , page_count
                    , range_scan_count
                    , scanDate
                )
                SELECT
                      ps.database_id AS 'databaseID'
                    , QUOTENAME(DB_NAME(ps.database_id)) AS 'databaseName'
                    , ps.OBJECT_ID AS 'objectID'
                    , ps.index_id AS 'indexID'
                    , ps.partition_number AS 'partitionNumber'
                    , SUM(ps.avg_fragmentation_in_percent) AS 'fragmentation'
                    , SUM(ps.page_count) AS 'page_count'
                    , os.range_scan_count
                    , GETDATE() AS 'scanDate'
                FROM sys.dm_db_index_physical_stats(@databaseID, OBJECT_ID(@tableName), Null , Null, @scanMode) AS ps
                Join sys.dm_db_index_operational_stats(@databaseID, OBJECT_ID(@tableName), Null , Null) AS os
                    ON ps.database_id = os.database_id
                    And ps.OBJECT_ID = os.OBJECT_ID
                    and ps.index_id = os.index_id
                    And ps.partition_number = os.partition_number
                WHERE avg_fragmentation_in_percent >= @minFragmentation 
                    And ps.index_id > 0 -- ignore heaps
                    And ps.page_count > @minPageCount 
                    And ps.index_level = 0 -- leaf-level nodes only, supports @scanMode
                GROUP BY ps.database_id 
                    , QUOTENAME(DB_NAME(ps.database_id)) 
                    , ps.OBJECT_ID 
                    , ps.index_id 
                    , ps.partition_number 
                    , os.range_scan_count
                OPTION (MaxDop 2);
 
                /* Do we want to exclude right-most populated partition of our partitioned indexes? */
                IF @excludeMaxPartition = 1
                BEGIN
 
                    SET @excludeMaxPartitionSQL = '
                        Select ' + CAST(@databaseID AS VARCHAR(10)) + ' As [databaseID]
                            , [object_id]
                            , index_id
                            , Max(partition_number) As [maxPartition]
                        From ' + DB_NAME(@databaseID) + '.sys.partitions
                        Where partition_number > 1
                            And [rows] > 0
                        Group By object_id
                            , index_id;';
 
                    INSERT INTO #maxPartitionList
                    EXECUTE SP_EXECUTESQL @excludeMaxPartitionSQL;
 
                END;
 
                /* Keep track of which databases have already been scanned */
                UPDATE #databaseList
                SET scanStatus = 1
                WHERE databaseID = @databaseID;
 
            END
 
            /* We don't want to defrag the right-most populated partition, so
               delete any records for partitioned indexes where partition = Max(partition) */
            IF @excludeMaxPartition = 1
            BEGIN
 
                DELETE ids
                FROM dbo.dba_indexDefragStatus AS ids
                Join #maxPartitionList AS mpl
                    ON ids.databaseID = mpl.databaseID
                    And ids.objectID = mpl.objectID
                    And ids.indexID = mpl.indexID
                    And ids.partitionNumber = mpl.maxPartition;
 
            END;
 
            /* Update our exclusion mask for any index that has a restriction on the days it can be defragged */
            UPDATE ids
            SET ids.exclusionMask = ide.exclusionMask
            FROM dbo.dba_indexDefragStatus AS ids
            Join dbo.dba_indexDefragExclusion AS ide
                ON ids.databaseID = ide.databaseID
                And ids.objectID = ide.objectID
                And ids.indexID = ide.indexID;
 
        END
 
        SELECT @debugMessage = 'Looping through our list... there are ' + CAST(COUNT(*) AS VARCHAR(10)) + ' indexes to defrag!'
        FROM dbo.dba_indexDefragStatus
        WHERE defragDate IS Null
            And page_count Between @minPageCount And IsNull(@maxPageCount, page_count);
 
        IF @debugMode = 1 RAISERROR(@debugMessage, 0, 42) WITH NoWait;
 
        /* Begin our loop for defragging */
        WHILE (SELECT COUNT(*) 
               FROM dbo.dba_indexDefragStatus 
               WHERE (
                           (@executeSQL = 1 And defragDate IS Null) 
                        Or (@executeSQL = 0 And defragDate IS Null And printStatus = 0)
                     )
                And exclusionMask & POWER(2, DATEPART(weekday, GETDATE())-1) = 0
                And page_count Between @minPageCount And IsNull(@maxPageCount, page_count)) > 0
        BEGIN
 
            /* Check to see if we need to exit our loop because of our time limit */        
            IF IsNull(@endDateTime, GETDATE()) < GETDATE()
            BEGIN
                RAISERROR('Our time limit has been exceeded!', 11, 42) WITH NoWait;
            END;
 
            IF @debugMode = 1 RAISERROR('  Picking an index to beat into shape...', 0, 42) WITH NoWait;
 
            /* Grab the index with the highest priority, based on the values submitted; 
               Look at the exclusion mask to ensure it can be defragged today */
            SET @getIndexSQL = N'
            Select Top 1 
                  @objectID_Out         = objectID
                , @indexID_Out          = indexID
                , @databaseID_Out       = databaseID
                , @databaseName_Out     = databaseName
                , @fragmentation_Out    = fragmentation
                , @partitionNumber_Out  = partitionNumber
                , @pageCount_Out        = page_count
            From dbo.dba_indexDefragStatus
            Where defragDate Is Null ' 
                + CASE WHEN @executeSQL = 0 THEN 'And printStatus = 0' ELSE '' END + '
                And exclusionMask & Power(2, DatePart(weekday, GetDate())-1) = 0
                And page_count Between @p_minPageCount and IsNull(@p_maxPageCount, page_count)
            Order By + ' + @defragOrderColumn + ' ' + @defragSortOrder;
 
            SET @getIndexSQL_Param = N'@objectID_Out        int OutPut
                                     , @indexID_Out         int OutPut
                                     , @databaseID_Out      int OutPut
                                     , @databaseName_Out    nvarchar(128) OutPut
                                     , @fragmentation_Out   int OutPut
                                     , @partitionNumber_Out int OutPut
                                     , @pageCount_Out       int OutPut
                                     , @p_minPageCount      int
                                     , @p_maxPageCount      int';
 
            EXECUTE SP_EXECUTESQL @getIndexSQL
                , @getIndexSQL_Param
                , @p_minPageCount       = @minPageCount
                , @p_maxPageCount       = @maxPageCount
                , @objectID_Out         = @objectID OUTPUT
                , @indexID_Out          = @indexID OUTPUT
                , @databaseID_Out       = @databaseID OUTPUT
                , @databaseName_Out     = @databaseName OUTPUT
                , @fragmentation_Out    = @fragmentation OUTPUT
                , @partitionNumber_Out  = @partitionNumber OUTPUT
                , @pageCount_Out        = @pageCount OUTPUT;
 
            IF @debugMode = 1 RAISERROR('  Looking up the specifics for our index...', 0, 42) WITH NoWait;
 
            /* Look up index information */
            SELECT @updateSQL = N'Update ids
                Set schemaName = QuoteName(s.name)
                    , objectName = QuoteName(o.name)
                    , indexName = QuoteName(i.name)
                From dbo.dba_indexDefragStatus As ids
                Inner Join ' + @databaseName + '.sys.objects As o
                    On ids.objectID = o.object_id
                Inner Join ' + @databaseName + '.sys.indexes As i
                    On o.object_id = i.object_id
                    And ids.indexID = i.index_id
                Inner Join ' + @databaseName + '.sys.schemas As s
                    On o.schema_id = s.schema_id
                Where o.object_id = ' + CAST(@objectID AS VARCHAR(10)) + '
                    And i.index_id = ' + CAST(@indexID AS VARCHAR(10)) + '
                    And i.type > 0
                    And ids.databaseID = ' + CAST(@databaseID AS VARCHAR(10));
 
            EXECUTE SP_EXECUTESQL @updateSQL;
 
            /* Grab our object names */
            SELECT @objectName  = objectName
                , @schemaName   = schemaName
                , @indexName    = indexName
            FROM dbo.dba_indexDefragStatus
            WHERE objectID = @objectID
                And indexID = @indexID
                And databaseID = @databaseID;
 
            IF @debugMode = 1 RAISERROR('  Grabbing the partition count...', 0, 42) WITH NoWait;
 
            /* Determine if the index is partitioned */
            SELECT @partitionSQL = 'Select @partitionCount_OUT = Count(*)
                                        From ' + @databaseName + '.sys.partitions
                                        Where object_id = ' + CAST(@objectID AS VARCHAR(10)) + '
                                            And index_id = ' + CAST(@indexID AS VARCHAR(10)) + ';'
                , @partitionSQL_Param = '@partitionCount_OUT int OutPut';
 
            EXECUTE SP_EXECUTESQL @partitionSQL, @partitionSQL_Param, @partitionCount_OUT = @partitionCount OUTPUT;
 
            IF @debugMode = 1 RAISERROR('  Seeing if there are any LOBs to be handled...', 0, 42) WITH NoWait;
 
            /* Determine if the table contains LOBs */
            SELECT @LOB_SQL = ' Select @containsLOB_OUT = Count(*)
                                From ' + @databaseName + '.sys.columns With (NoLock) 
                                Where [object_id] = ' + CAST(@objectID AS VARCHAR(10)) + '
                                   And (system_type_id In (34, 35, 99)
                                            Or max_length = -1);'
                                /*  system_type_id --> 34 = image, 35 = text, 99 = ntext
                                    max_length = -1 --> varbinary(max), varchar(max), nvarchar(max), xml */
                    , @LOB_SQL_Param = '@containsLOB_OUT int OutPut';
 
            EXECUTE SP_EXECUTESQL @LOB_SQL, @LOB_SQL_Param, @containsLOB_OUT = @containsLOB OUTPUT;
 
            IF @debugMode = 1 RAISERROR('  Checking for indexes that do not allow page locks...', 0, 42) WITH NoWait;
 
            /* Determine if page locks are allowed; for those indexes, we need to always rebuild */
            SELECT @allowPageLockSQL = 'Select @allowPageLocks_OUT = Count(*)
                                        From ' + @databaseName + '.sys.indexes
                                        Where object_id = ' + CAST(@objectID AS VARCHAR(10)) + '
                                            And index_id = ' + CAST(@indexID AS VARCHAR(10)) + '
                                            And Allow_Page_Locks = 0;'
                , @allowPageLockSQL_Param = '@allowPageLocks_OUT int OutPut';
 
            EXECUTE SP_EXECUTESQL @allowPageLockSQL, @allowPageLockSQL_Param, @allowPageLocks_OUT = @allowPageLocks OUTPUT;
 
            IF @debugMode = 1 RAISERROR('  Building our SQL statements...', 0, 42) WITH NoWait;
 
            /* If there's not a lot of fragmentation, or if we have a LOB, we should reorganize */
            IF (@fragmentation < @rebuildThreshold Or @containsLOB >= 1 Or @partitionCount > 1)
                And @allowPageLocks = 0
            BEGIN
 
                SET @sqlCommand = N'Alter Index ' + @indexName + N' On ' + @databaseName + N'.' 
                                    + @schemaName + N'.' + @objectName + N' ReOrganize';
 
                /* If our index is partitioned, we should always reorganize */
                IF @partitionCount > 1
                    SET @sqlCommand = @sqlCommand + N' Partition = ' 
                                    + CAST(@partitionNumber AS NVARCHAR(10));
 
            END
            /* If the index is heavily fragmented and doesn't contain any partitions or LOB's, 
               or if the index does not allow page locks, rebuild it */
            ELSE IF (@fragmentation >= @rebuildThreshold Or @allowPageLocks <> 0)
                And IsNull(@containsLOB, 0) != 1 And @partitionCount <= 1
            BEGIN
 
                /* Set online rebuild options; requires Enterprise Edition */
                IF @onlineRebuild = 1 And @editionCheck = 1 
                    SET @rebuildCommand = N' Rebuild With (Online = On';
                ELSE
                    SET @rebuildCommand = N' Rebuild With (Online = Off';
 
                /* Set sort operation preferences */
                IF @sortInTempDB = 1 
                    SET @rebuildCommand = @rebuildCommand + N', Sort_In_TempDB = On';
                ELSE
                    SET @rebuildCommand = @rebuildCommand + N', Sort_In_TempDB = Off';
 
                /* Set processor restriction options; requires Enterprise Edition */
                IF @maxDopRestriction IS Not Null And @editionCheck = 1
                    SET @rebuildCommand = @rebuildCommand + N', MaxDop = ' + CAST(@maxDopRestriction AS VARCHAR(2)) + N')';
                ELSE
                    SET @rebuildCommand = @rebuildCommand + N')';
 
                SET @sqlCommand = N'Alter Index ' + @indexName + N' On ' + @databaseName + N'.'
                                + @schemaName + N'.' + @objectName + @rebuildCommand;
 
            END
            ELSE
                /* Print an error message if any indexes happen to not meet the criteria above */
                IF @printCommands = 1 Or @debugMode = 1
                    RAISERROR('We are unable to defrag this index.', 0, 42) WITH NoWait;
 
            /* Are we executing the SQL?  If so, do it */
            IF @executeSQL = 1
            BEGIN
 
                SET @debugMessage = 'Executing: ' + @sqlCommand;
 
                /* Print the commands we're executing if specified to do so */
                IF @printCommands = 1 Or @debugMode = 1
                    RAISERROR(@debugMessage, 0, 42) WITH NoWait;
 
                /* Grab the time for logging purposes */
                SET @dateTimeStart  = GETDATE();
 
                /* Log our actions */
                INSERT INTO dbo.dba_indexDefragLog
                (
                      databaseID
                    , databaseName
                    , objectID
                    , objectName
                    , indexID
                    , indexName
                    , partitionNumber
                    , fragmentation
                    , page_count
                    , dateTimeStart
                    , sqlStatement
                )
                SELECT
                      @databaseID
                    , @databaseName
                    , @objectID
                    , @objectName
                    , @indexID
                    , @indexName
                    , @partitionNumber
                    , @fragmentation
                    , @pageCount
                    , @dateTimeStart
                    , @sqlCommand;
 
                SET @indexDefrag_id = SCOPE_IDENTITY();
 
                /* Wrap our execution attempt in a try/catch and log any errors that occur */
                BEGIN Try
 
                    /* Execute our defrag! */
                    EXECUTE SP_EXECUTESQL @sqlCommand;
                    SET @dateTimeEnd = GETDATE();
 
                    /* Update our log with our completion time */
                    UPDATE dbo.dba_indexDefragLog
                    SET dateTimeEnd = @dateTimeEnd
                        , durationSeconds = DATEDIFF(SECOND, @dateTimeStart, @dateTimeEnd)
                    WHERE indexDefrag_id = @indexDefrag_id;
 
                END Try
                BEGIN Catch
 
                    /* Update our log with our error message */
                    UPDATE dbo.dba_indexDefragLog
                    SET dateTimeEnd = GETDATE()
                        , durationSeconds = -1
                        , errorMessage = Error_Message()
                    WHERE indexDefrag_id = @indexDefrag_id;
 
                    IF @debugMode = 1 
                        RAISERROR('  An error has occurred executing this command! Please review the dba_indexDefragLog table for details.'
                            , 0, 42) WITH NoWait;
 
                END Catch
 
                /* Just a little breather for the server */
                WAITFOR Delay @defragDelay;
 
                UPDATE dbo.dba_indexDefragStatus
                SET defragDate = GETDATE()
                    , printStatus = 1
                WHERE databaseID       = @databaseID
                  And objectID         = @objectID
                  And indexID          = @indexID
                  And partitionNumber  = @partitionNumber;
 
            END
            ELSE
            /* Looks like we're not executing, just printing the commands */
            BEGIN
                IF @debugMode = 1 RAISERROR('  Printing SQL statements...', 0, 42) WITH NoWait;
 
                IF @printCommands = 1 Or @debugMode = 1 
                    PRINT IsNull(@sqlCommand, 'error!');
 
                UPDATE dbo.dba_indexDefragStatus
                SET printStatus = 1
                WHERE databaseID       = @databaseID
                  And objectID         = @objectID
                  And indexID          = @indexID
                  And partitionNumber  = @partitionNumber;
            END
 
        END
 
        /* Do we want to output our fragmentation results? */
        IF @printFragmentation = 1
        BEGIN
 
            IF @debugMode = 1 RAISERROR('  Displaying a summary of our action...', 0, 42) WITH NoWait;
 
            SELECT databaseID
                , databaseName
                , objectID
                , objectName
                , indexID
                , indexName
                , partitionNumber
                , fragmentation
                , page_count
                , range_scan_count
            FROM dbo.dba_indexDefragStatus
            WHERE defragDate >= @startDateTime
            ORDER BY defragDate;
 
        END;
 
    END Try
    BEGIN Catch
 
        SET @debugMessage = Error_Message() + ' (Line Number: ' + CAST(Error_Line() AS VARCHAR(10)) + ')';
        PRINT @debugMessage;
 
    END Catch;
 
    /* When everything is said and done, make sure to get rid of our temp table */
    DROP TABLE #databaseList;
    DROP TABLE #processor;
    DROP TABLE #maxPartitionList;
 
    IF @debugMode = 1 RAISERROR('DONE!  Thank you for taking care of your indexes!  :)', 0, 42) WITH NoWait;
 
    SET NOCOUNT OFF;
    RETURN 0
END

You can also download it here: dba_indexDefrag_sp_v40_public.txt

I've had this latest version in production on terabyte-size databases running SQL Server 2005 and 2008 Enterprise editions for the last 3 months, where it runs nightly without issue. I've also had numerous beta testers report success in their environments, too. But to be safe, make sure to keep an eye on it the first time it runs to ensure you understand the impact on your server.

Enjoy!

Michelle

Tagged as: , , , , , , , , , , , 39 Comments
3Aug/096

Find Recently Executed Stored Procedures

This past weekend, we had an issue where replication fell far behind on one of our databases. The replicated database is used for all sorts of reporting, so the immediate need was to identify processes that may have been affected by the incomplete data.

Now, there's hundreds of stored procedures that reference the affected database; the trick is finding out which ones are relevant. To do this, I used the sys.dm_exec_query_stats DMV. This does two things for me. One, it shows me a list of stored procedures in cache, meaning they've been executed relatively recently and are probably relevant to the search. Secondly, it shows me the last execution time, which in some cases may have been before the issue, meaning I do not need to worry about re-running those processes.

Here's the query I used:

SELECT DB_NAME(dest.[dbid]) AS 'databaseName'
    , OBJECT_NAME(dest.objectid, dest.[dbid]) AS 'procName'
    , MAX(deqs.last_execution_time) AS 'last_execution'
FROM sys.dm_exec_query_stats AS deqs
Cross Apply sys.dm_exec_sql_text(deqs.sql_handle) AS dest
WHERE dest.[TEXT] Like '%yourTableName%' -- replace
    And dest.[dbid] IS Not Null  -- exclude ad-hocs
GROUP BY DB_NAME(dest.[dbid])
    , OBJECT_NAME(dest.objectid, dest.[dbid])
ORDER BY databaseName
    , procName
OPTION (MaxDop 1);

This will return results similar to:

databaseName         procName                       last_execution
-------------------- ------------------------------ -----------------------
AdventureWorks       ufnGetProductListPrice         2009-08-03 09:57:25.390
AdventureWorksDW     DimProductCategoryGet_sp       2009-08-03 09:59:05.820
AdventureWorksDW     DimProductGet_sp               2009-08-03 09:58:38.370

I want to stress that this is *not* a list of all referencing objects, but rather a list of recently executed stored procedures that are still in memory. This list may not be accurate if your cache has recently been flushed or if you've recently rebooted your server.

Tagged as: , , , 6 Comments
29Jul/098

Poor (Wo)Man’s Graph

Lary shared this poor (wo)man's graph with me today, and I thought it was pretty awesome:

SELECT OrderDate 
    , COUNT(*) AS 'orders'
    , REPLICATE('=', COUNT(*)) AS 'orderGraph'
    , SUM(TotalDue) AS 'revenue'
    , REPLICATE('$', SUM(TotalDue)/1000) AS 'revenueGraph'
FROM AdventureWorks.Sales.SalesOrderHeader
WHERE OrderDate Between '2003-07-15' And '2003-07-31'
GROUP BY OrderDate
ORDER BY OrderDate;

This will return a simple but effective "graph" for you:

orderDate  orders orderGraph                     revenue  revenueGraph
---------- ------ ------------------------------ -------- ----------------------------------------
2003-07-15 19     ===================            34025.24 $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$      
2003-07-16 14     ==============                 26687.65 $$$$$$$$$$$$$$$$$$$$$$$$$$$             
2003-07-17 16     ================               32411.93 $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$        
2003-07-18 9      =========                      18634.91 $$$$$$$$$$$$$$$$$$$                     
2003-07-19 13     =============                  19603.23 $$$$$$$$$$$$$$$$$$$$                    
2003-07-20 24     ========================       47522.80 $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
2003-07-21 9      =========                      11781.62 $$$$$$$$$$$$                            
2003-07-22 17     =================              32322.50 $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$        
2003-07-23 15     ===============                30906.44 $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$         
2003-07-24 28     ============================   51107.90 $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
2003-07-25 15     ===============                27058.10 $$$$$$$$$$$$$$$$$$$$$$$$$$$             
2003-07-26 18     ==================             41076.49 $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
2003-07-27 15     ===============                22169.88 $$$$$$$$$$$$$$$$$$$$$$                  
2003-07-28 16     ================               23945.80 $$$$$$$$$$$$$$$$$$$$$$$$                
2003-07-29 25     =========================      51122.95 $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
2003-07-30 12     ============                   23476.44 $$$$$$$$$$$$$$$$$$$$$$$                 
2003-07-31 18     ==================             36266.76 $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$

Who needs Reporting Services when you've got REPLICATE? ;)

Tagged as: , 8 Comments
9Jul/093

Index Defrag Script Update

A couple of people pointed out to me that the stats rebuild feature in my defrag script will only complete for one database. Whoopsies! I've fixed the bug and updated the script in my previous post, so if you're using my defrag script, please update it. Thanks to Derick and SuperCoolMoss for letting me know about the bug.

I've also received a couple of other requests for feature enhancements. I'm currently swamped at work and outside of work, but as soon as I get time, I will release the latest version. Realistically, it'll probably be sometime after summer ends. :)

Thank you to everyone for their comments and suggestions!

Tagged as: , , , , , 3 Comments
4Jun/097

Random Number Generator in T-SQL

Ever need to generate a random number in T-SQL? I have, on a couple of different occasions. I'm pretty sure that there's several different ways of doing this in T-SQL, but here's what I use:

DECLARE @maxRandomValue TINYINT = 100
	, @minRandomValue TINYINT = 0;
 
SELECT CAST(((@maxRandomValue + 1) - @minRandomValue) 
	* RAND() + @minRandomValue AS TINYINT) AS 'randomNumber';

This approach uses the RAND() function to generate a random seed; it also ensures that the value returned is between the specified min and max value. I've been using this method in one stored procedure that's called a couple of hundred times per second, and it seems to perform pretty well.

What method do YOU use to generate a random number? Is it faster than this method?

Tagged as: , , 7 Comments
17Nov/0820

Updated Index Defrag Script (2005, 2008)

Thanks to everyone who left a comment or sent me an e-mail regarding the Index Defrag Script. I've received some great feedback and requests for features. I've also had some questions regarding how to use it, which I will answer at the end of this post.

Changes include:
- separate version for both Enterprise and Standard editions
    - Standard edition removes partitioning and online options
- output option to see fragmentation levels
- page_count added to the log table

I've also verified that this script works well in SQL 2008.

Enterprise Version:

IF EXISTS(SELECT OBJECT_ID FROM sys.tables
                WHERE [name] = N'dba_indexDefragLog')
BEGIN
 
    DROP TABLE dbo.dba_indexDefragLog;
 
    PRINT 'dba_indexDefragLog table dropped!';
 
END
 
CREATE TABLE dbo.dba_indexDefragLog
(
      indexDefrag_id    INT IDENTITY(1,1)   NOT NULL
    , objectID          INT                 NOT NULL
    , objectName        NVARCHAR(130)       NOT NULL
    , indexID           INT                 NOT NULL
    , indexName         NVARCHAR(130)       NOT NULL
    , partitionNumber   SMALLINT            not null
    , fragmentation     FLOAT               NOT NULL
    , page_count        INT                 NOT NULL
    , dateTimeStart     DATETIME            NOT NULL
    , durationSeconds   INT                 NOT NULL
    CONSTRAINT PK_indexDefragLog
        PRIMARY KEY CLUSTERED (indexDefrag_id)
);
 
PRINT 'dba_indexDefragLog Table Created';
 
IF OBJECTPROPERTY(OBJECT_ID('dbo.dba_indexDefrag_sp'),
        N'IsProcedure') IS Null
BEGIN
    EXECUTE ('Create Procedure dbo.dba_indexDefrag_sp
        As Print ''Hello World!''');
    RAISERROR('Procedure dba_indexDefrag_sp created.'
        , 10, 1);
END;
Go
 
SET ANSI_Nulls ON;
SET Ansi_Padding ON;
SET Ansi_Warnings ON;
SET ArithAbort ON;
SET Concat_Null_Yields_Null ON;
SET NOCOUNT ON;
SET Numeric_RoundAbort OFF;
SET Quoted_Identifier ON;
Go
 
ALTER PROCEDURE dbo.dba_indexDefrag_sp
 
    /* Declare Parameters */
      @minFragmentation     FLOAT           = 10.0
        /* in percent, will not defrag if fragmentation
           less than specified */
    , @rebuildThreshold     FLOAT           = 30.0
        /* in percent, greater than @rebuildThreshold
           will result in rebuild instead of reorg */
    , @onlineRebuild        BIT             = 1     
        /* 1 = online rebuild; 0 = offline rebuild */
    , @executeSQL           BIT             = 1
        /* 1 = execute; 0 = print command only */
    , @tableName            VARCHAR(4000)   = Null 
        /* Option to specify a table name */
    , @printCommands        BIT             = 0
        /* 1 = print commands; 0 = do not print commands */
    , @printFragmentation   BIT             = 0
        /* 1 = print fragmentation prior to defrag; 
           0 = do not print */
    , @defragDelay          CHAR(8)         = '00:00:05'
        /* time to wait between defrag commands */
AS
/********************************************************************
    Name:       dba_indexDefrag_sp
 
    Author:     Michelle F. Ufford
 
    Purpose:    Defrags all indexes for the current database
 
    Notes:      This script was designed for SQL Server 2005
                Enterprise Edition.
 
    CAUTION: Monitor transaction log if executing for the first time!
 
      @minFragmentation     defaulted to 10%, will not defrag if
                            fragmentation if less than specified.
 
      @rebuildThreshold     defaulted to 30% as recommended by
                            Microsoft in BOL;
                            > than 30% will result in rebuild instead
 
      @onlineRebuild        1 = online rebuild; 
                            0 = offline rebuild
 
      @executeSQL           1 = execute the SQL generated by this proc;
                            0 = print command only
 
      @tableName            Specify if you only want to defrag indexes
                            for a specific table
 
      @printCommands        1 = print commands to screen;
                            0 = do not print commands
 
      @printFragmentation   1 = print fragmentation to screen;
                            0 = do not print fragmentation
 
      @defragDelay          time to wait between defrag commands;
                            gives the server some time to catch up
 
    Called by:  SQL Agent Job or DBA
 
    Date        Initials  Description
    ----------------------------------------------------------------
    2008-10-27  MFU       Initial Release
    2008-11-17  MFU       Added page_count to log table
                          , added @printFragmentation option
********************************************************************
    Exec dbo.dba_indexDefrag_sp
          @executeSQL         = 1
        , @printCommands      = 1
        , @minFragmentation   = 0
        , @printFragmentation = 1;
********************************************************************/
 
SET NOCOUNT ON;
SET XACT_Abort ON;
 
BEGIN
 
    /* Declare our variables */
    DECLARE   @objectID         INT
            , @indexID          INT
            , @partitionCount   BIGINT
            , @schemaName       NVARCHAR(130)
            , @objectName       NVARCHAR(130)
            , @indexName        NVARCHAR(130)
            , @partitionNumber  SMALLINT
            , @partitions       SMALLINT
            , @fragmentation    FLOAT
            , @pageCount        INT
            , @sqlCommand       NVARCHAR(4000)
            , @rebuildCommand   NVARCHAR(200)
            , @dateTimeStart    DATETIME
            , @dateTimeEnd      DATETIME
            , @containsLOB      BIT;
 
    /* Just a little validation... */
    IF @minFragmentation Not Between 0.00 And 100.0
        SET @minFragmentation = 10.0;
 
    IF @rebuildThreshold Not Between 0.00 And 100.0
        SET @rebuildThreshold = 30.0;
 
    IF @defragDelay Not Like '00:[0-5][0-9]:[0-5][0-9]'
        SET @defragDelay = '00:00:05';
 
    /* Determine which indexes to defrag using our
       user-defined parameters */
    SELECT
          OBJECT_ID AS objectID
        , index_id AS indexID
        , partition_number AS partitionNumber
        , avg_fragmentation_in_percent AS fragmentation
        , page_count 
        , 0 AS 'defragStatus'
            /* 0 = unprocessed, 1 = processed */
    INTO #indexDefragList
    FROM sys.dm_db_index_physical_stats
        (DB_ID(), OBJECT_ID(@tableName), NULL , NULL, N'Limited')
    WHERE avg_fragmentation_in_percent > @minFragmentation
        And index_id > 0
    OPTION (MaxDop 1);
 
    /* Create a clustered index to boost performance a little */
    CREATE CLUSTERED INDEX CIX_temp_indexDefragList
        ON #indexDefragList(objectID, indexID, partitionNumber);
 
    /* Begin our loop for defragging */
    WHILE (SELECT COUNT(*) FROM #indexDefragList
            WHERE defragStatus = 0) > 0
    BEGIN
 
        /* Grab the most fragmented index first to defrag */
        SELECT TOP 1
              @objectID         = objectID
            , @fragmentation    = fragmentation
            , @indexID          = indexID
            , @partitionNumber  = partitionNumber
            , @pageCount        = page_count
        FROM #indexDefragList
        WHERE defragStatus = 0
        ORDER BY fragmentation DESC;
 
        /* Look up index information */
        SELECT @objectName = QUOTENAME(o.name)
             , @schemaName = QUOTENAME(s.name)
        FROM sys.objects AS o
        INNER Join sys.schemas AS s
            ON s.schema_id = o.schema_id
        WHERE o.OBJECT_ID = @objectID;
 
        SELECT @indexName = QUOTENAME(name)
        FROM sys.indexes
        WHERE OBJECT_ID = @objectID
            And index_id = @indexID
            And type > 0;
 
        /* Determine if the index is partitioned */
        SELECT @partitionCount = COUNT(*)
        FROM sys.partitions
        WHERE OBJECT_ID = @objectID
            And index_id = @indexID;
 
        /* Look for LOBs */
        SELECT TOP 1
            @containsLOB = column_id
        FROM sys.columns WITH (NOLOCK)
        WHERE 
            [OBJECT_ID] = @objectID
            And (system_type_id In (34, 35, 99)
            -- 34 = image, 35 = text, 99 = ntext
                    Or max_length = -1);
            -- varbinary(max), varchar(max), nvarchar(max), xml
 
        /* See if we should rebuild or reorganize; handle thusly */
        IF @fragmentation < @rebuildThreshold And @partitionCount <= 1
            SET @sqlCommand = N'Alter Index ' + @indexName + N' On '
                + @schemaName + N'.' + @objectName + N' ReOrganize';
 
        IF @fragmentation >= @rebuildThreshold
            And IsNull(@containsLOB, 0) = 0
                -- Cannot rebuild if the table has one or more LOB
            And @partitionCount <= 1
        BEGIN
 
            /* We should always rebuild online if possible
                (SQL 2005 Enterprise) */
            IF @onlineRebuild = 0
                SET @rebuildCommand = N' Rebuild With
                    (Online = Off, MaxDop = 1)';
            ELSE
                SET @rebuildCommand = N' Rebuild With
                    (Online = On, MaxDop = 1)';
 
            SET @sqlCommand = N'Alter Index ' + @indexName + N' On '
                + @schemaName + N'.' + @objectName + @rebuildCommand;
        END;
 
        /* If our index is partitioned, we should always reorganize */
        IF @partitionCount > 1
            SET @sqlCommand = N'Alter Index ' + @indexName + N' On '
                + @schemaName + N'.' + @objectName + N' ReOrganize'
                + N' Partition = '
                + CAST(@partitionNumber AS NVARCHAR(10));
                -- no MaxDop needed, single threaded operation
 
        /* Are we executing the SQL?  If so, do it */
        IF @executeSQL = 1
        BEGIN
 
            /* Grab the time for logging purposes */
            SET @dateTimeStart  = GETDATE();
            EXECUTE (@sqlCommand);
            SET @dateTimeEnd  = GETDATE();
 
            /* Log our actions */
            INSERT INTO dbo.dba_indexDefragLog
            (
                  objectID
                , objectName
                , indexID
                , indexName
                , partitionNumber
                , fragmentation
                , page_count
                , dateTimeStart
                , durationSeconds
            )
            SELECT
                  @objectID
                , @objectName
                , @indexID
                , @indexName
                , @partitionNumber
                , @fragmentation
                , @pageCount
                , @dateTimeStart
                , DATEDIFF(SECOND, @dateTimeStart, @dateTimeEnd);
 
            /* Just a little breather for the server */
            WAITFOR Delay @defragDelay;
 
            /* Print if specified to do so */
            IF @printCommands = 1
                PRINT N'Executed: ' + @sqlCommand;
        END
        ELSE
        /* Looks like we're not executing, just print
            the commands */
        BEGIN
            IF @printCommands = 1
                PRINT @sqlCommand;
        END
 
        /* Update our index defrag list when we've
            finished with that index */
        UPDATE #indexDefragList
        SET defragStatus = 1
        WHERE objectID         = @objectID
          And indexID          = @indexID
          And partitionNumber  = @partitionNumber;
 
    END
 
    /* Do we want to output our fragmentation results? */
    IF @printFragmentation = 1
        SELECT idl.objectID
            , o.name AS 'tableName'
            , idl.indexID
            , i.name AS 'indexName'
            , idl.fragmentation
            , idl.page_count
        FROM #indexDefragList AS idl
        Join sys.objects AS o
            ON idl.objectID = o.OBJECT_ID
        Join sys.indexes AS i
            ON idl.objectID = i.OBJECT_ID
            And idl.indexID = i.index_id;
 
    /* When everything is done, make sure to get rid of
        our temp table */
    DROP TABLE #indexDefragList;
 
    SET NOCOUNT OFF;
    RETURN 0
END
Go

 

Standard Version:

IF EXISTS(SELECT OBJECT_ID FROM sys.tables
                WHERE [name] = N'dba_indexDefragLog')
BEGIN
 
    DROP TABLE dbo.dba_indexDefragLog;
 
    PRINT 'dba_indexDefragLog table dropped!';
 
END
 
CREATE TABLE dbo.dba_indexDefragLog
(
      indexDefrag_id    INT IDENTITY(1,1)   NOT NULL
    , objectID          INT                 NOT NULL
    , objectName        NVARCHAR(130)       NOT NULL
    , indexID           INT                 NOT NULL
    , indexName         NVARCHAR(130)       NOT NULL
    , fragmentation     FLOAT               NOT NULL
    , page_count        INT                 NOT NULL
    , dateTimeStart     DATETIME            NOT NULL
    , durationSeconds   INT                 NOT NULL
    CONSTRAINT PK_indexDefragLog
        PRIMARY KEY CLUSTERED (indexDefrag_id)
);
 
PRINT 'dba_indexDefragLog Table Created';
 
IF OBJECTPROPERTY(OBJECT_ID('dbo.dba_indexDefragStandard_sp'),
        N'IsProcedure') IS Null
BEGIN
    EXECUTE ('Create Procedure dbo.dba_indexDefragStandard_sp
        As Print ''Hello World!''');
    RAISERROR('Procedure dba_indexDefragStandard_sp created.'
        , 10, 1);
END;
Go
 
SET ANSI_Nulls ON;
SET Ansi_Padding ON;
SET Ansi_Warnings ON;
SET ArithAbort ON;
SET Concat_Null_Yields_Null ON;
SET NOCOUNT ON;
SET Numeric_RoundAbort OFF;
SET Quoted_Identifier ON;
Go
 
ALTER PROCEDURE dbo.dba_indexDefragStandard_sp
 
    /* Declare Parameters */
      @minFragmentation     FLOAT           = 10.0
        /* in percent, will not defrag if fragmentation
           less than specified */
    , @rebuildThreshold     FLOAT           = 30.0
        /* in percent, greater than @rebuildThreshold
           will result in rebuild instead of reorg */
    , @executeSQL           BIT             = 1
        /* 1 = execute; 0 = print command only */
    , @tableName            VARCHAR(4000)   = Null 
        /* Option to specify a table name */
    , @printCommands        BIT             = 0
        /* 1 = print commands; 0 = do not print commands */
    , @printFragmentation   BIT             = 0
        /* 1 = print fragmentation prior to defrag; 
           0 = do not print */
    , @defragDelay          CHAR(8)         = '00:00:05'
        /* time to wait between defrag commands */
AS
/********************************************************************
    Name:       dba_indexDefragStandard_sp
 
    Author:     Michelle F. Ufford
 
    Purpose:    Defrags all indexes for the current database
 
    Notes:      This script was designed for SQL Server 2005
                Standard edition.
 
    CAUTION: Monitor transaction log if executing for the first time!
 
      @minFragmentation     defaulted to 10%, will not defrag if
                            fragmentation if less than specified.
 
      @rebuildThreshold     defaulted to 30% as recommended by
                            Microsoft in BOL;
                            > than 30% will result in rebuild instead
 
      @executeSQL           1 = execute the SQL generated by this proc;
                            0 = print command only
 
      @tableName            Specify if you only want to defrag indexes
                            for a specific table
 
      @printCommands        1 = print commands to screen;
                            0 = do not print commands
 
      @printFragmentation   1 = print fragmentation to screen;
                            0 = do not print fragmentation
 
      @defragDelay          time to wait between defrag commands;
                            gives the server some time to catch up
 
    Called by:  SQL Agent Job or DBA
 
    Date        Initials  Description
    ----------------------------------------------------------------
    2008-10-27  MFU       Initial Release
    2008-11-17  MFU       Added page_count to log table
                          , added @printFragmentation option
********************************************************************
    Exec dbo.dba_indexDefragStandard_sp
          @executeSQL         = 1
        , @printCommands      = 1
        , @minFragmentation   = 0
        , @printFragmentation = 1;
********************************************************************/
 
SET NOCOUNT ON;
SET XACT_Abort ON;
 
BEGIN
 
    /* Declare our variables */
    DECLARE   @objectID         INT
            , @indexID          INT
            , @schemaName       NVARCHAR(130)
            , @objectName       NVARCHAR(130)
            , @indexName        NVARCHAR(130)
            , @fragmentation    FLOAT
            , @pageCount        INT
            , @sqlCommand       NVARCHAR(4000)
            , @rebuildCommand   NVARCHAR(200)
            , @dateTimeStart    DATETIME
            , @dateTimeEnd      DATETIME
            , @containsLOB      BIT;
 
    /* Just a little validation... */
    IF @minFragmentation Not Between 0.00 And 100.0
        SET @minFragmentation = 10.0;
 
    IF @rebuildThreshold Not Between 0.00 And 100.0
        SET @rebuildThreshold = 30.0;
 
    IF @defragDelay Not Like '00:[0-5][0-9]:[0-5][0-9]'
        SET @defragDelay = '00:00:05';
 
    /* Determine which indexes to defrag using our
       user-defined parameters */
    SELECT
          OBJECT_ID AS objectID
        , index_id AS indexID
        , avg_fragmentation_in_percent AS fragmentation
        , page_count 
        , 0 AS 'defragStatus'
            /* 0 = unprocessed, 1 = processed */
    INTO #indexDefragList
    FROM sys.dm_db_index_physical_stats
        (DB_ID(), OBJECT_ID(@tableName), NULL , NULL, N'Limited')
    WHERE avg_fragmentation_in_percent > @minFragmentation
        And index_id > 0
    OPTION (MaxDop 1);
 
    /* Create a clustered index to boost performance a little */
    CREATE CLUSTERED INDEX CIX_temp_indexDefragList
        ON #indexDefragList(objectID, indexID);
 
    /* Begin our loop for defragging */
    WHILE (SELECT COUNT(*) FROM #indexDefragList
            WHERE defragStatus = 0) > 0
    BEGIN
 
        /* Grab the most fragmented index first to defrag */
        SELECT TOP 1
              @objectID         = objectID
            , @fragmentation    = fragmentation
            , @indexID          = indexID
            , @pageCount        = page_count
        FROM #indexDefragList
        WHERE defragStatus = 0
        ORDER BY fragmentation DESC;
 
        /* Look up index information */
        SELECT @objectName = QUOTENAME(o.name)
             , @schemaName = QUOTENAME(s.name)
        FROM sys.objects AS o
        INNER Join sys.schemas AS s
            ON s.schema_id = o.schema_id
        WHERE o.OBJECT_ID = @objectID;
 
        SELECT @indexName = QUOTENAME(name)
        FROM sys.indexes
        WHERE OBJECT_ID = @objectID
            And index_id = @indexID
            And type > 0;
 
        /* Look for LOBs */
        SELECT TOP 1
            @containsLOB = column_id
        FROM sys.columns WITH (NOLOCK)
        WHERE 
            [OBJECT_ID] = @objectID
            And (system_type_id In (34, 35, 99)
            -- 34 = image, 35 = text, 99 = ntext
                    Or max_length = -1);
            -- varbinary(max), varchar(max), nvarchar(max), xml
 
        /* See if we should rebuild or reorganize; handle thusly */
        IF @fragmentation < @rebuildThreshold 
            Or IsNull(@containsLOB, 0) > 0 
            -- Cannot rebuild if the table has one or more LOB
            SET @sqlCommand = N'Alter Index ' + @indexName + N' On '
                + @schemaName + N'.' + @objectName + N' ReOrganize;'
        ELSE
            SET @sqlCommand = N'Alter Index ' + @indexName + N' On '
                + @schemaName + N'.' + @objectName +  ' Rebuild '
                + 'With (MaxDop = 1)'; -- minimize impact on server
 
        /* Are we executing the SQL?  If so, do it */
        IF @executeSQL = 1
        BEGIN
 
            /* Grab the time for logging purposes */
            SET @dateTimeStart  = GETDATE();
            EXECUTE (@sqlCommand);
            SET @dateTimeEnd  = GETDATE();
 
            /* Log our actions */
            INSERT INTO dbo.dba_indexDefragLog
            (
                  objectID
                , objectName
                , indexID
                , indexName
                , fragmentation
                , page_count
                , dateTimeStart
                , durationSeconds
            )
            SELECT
                  @objectID
                , @objectName
                , @indexID
                , @indexName
                , @fragmentation
                , @pageCount
                , @dateTimeStart
                , DATEDIFF(SECOND, @dateTimeStart, @dateTimeEnd);
 
            /* Just a little breather for the server */
            WAITFOR Delay @defragDelay;
 
            /* Print if specified to do so */
            IF @printCommands = 1
                PRINT N'Executed: ' + @sqlCommand;
        END
        ELSE
        /* Looks like we're not executing, just print
            the commands */
        BEGIN
            IF @printCommands = 1
                PRINT @sqlCommand;
        END
 
        /* Update our index defrag list when we've
            finished with that index */
        UPDATE #indexDefragList
        SET defragStatus = 1
        WHERE objectID  = @objectID
          And indexID   = @indexID;
 
    END
 
    /* Do we want to output our fragmentation results? */
    IF @printFragmentation = 1
        SELECT idl.objectID
            , o.name AS 'tableName'
            , idl.indexID
            , i.name AS 'indexName'
            , idl.fragmentation
            , idl.page_count
        FROM #indexDefragList AS idl
        JOIN sys.objects AS o
            ON idl.objectID = o.OBJECT_ID
        JOIN sys.indexes AS i
            ON idl.objectID = i.OBJECT_ID
            AND idl.indexID = i.index_id;
 
    /* When everything is done, make sure to get rid of
        our temp table */
    DROP TABLE #indexDefragList;
 
    SET NOCOUNT OFF;
    RETURN 0
END
Go

 

For those who are having troubles with this script...

1) "Not all of my indexes were defragged!" or "Nothing happened when I executed this script."

This script will only defrag those indexes that surpass the specified threshold. If you're not seeing your index in the output, try executing this:

    EXEC dbo.dba_indexDefrag_sp
          @executeSQL    = 0
        , @printCommands = 1
        , @minFragmentation = 0
        , @printFragmentation = 1;

Check to see what your index's fragmentation level is. Maybe it's not as fragmented as you feared. :)

2) "My indexes are still fragmented after running this script."

To quote The Powers That Be (aka Microsoft)...

"In general, fragmentation on small indexes is often not controllable. The pages of small indexes are stored on mixed extents. Mixed extents are shared by up to eight objects, so the fragmentation in a small index might not be reduced after reorganizing or rebuilding the index." -- Reorganizing and Rebuilding Indexes

3) "Can I use this in my production environment?"

That really depends on your environment. I've successfully used this in some very large production environments. However, I wouldn't exactly recommend executing the script in the middle of a business day on a billion+ row, heavily fragmented, unpartitioned table, either. :)

If you're not sure what the impact will be, execute the commands-only version of the script...

    EXEC dbo.dba_indexDefrag_sp
	      @executeSQL    = 0
        , @printCommands = 1
        , @printFragmentation = 1;

... then execute the statements one at a time. Make sure you monitor tempdb and the transaction log to ensure you don't have any space issues.

If you have any additional questions or suggestions for this script, leave me a comment and I'll be happy to help. :)

Tagged as: , , , , , 20 Comments
12Nov/080

One-to-Many Inserts with Table-Valued Parameters

There's been much talk about table-valued parameters, but I've yet to see an example illustrating one of the greatest potential benefits of this new feature (at least, imho): one-to-many inserts.

But first, for those not yet up to speed on this new feature...

What are Table-Valued Parameters?

According to SQL Books Online 2008:

Table-valued parameters are a new parameter type in SQL Server 2008. Table-valued parameters are declared by using user-defined table types. You can use table-valued parameters to send multiple rows of data to a Transact-SQL statement or a routine, such as a stored procedure or function, without creating a temporary table or many parameters.

That's great, but why do I care?

This means that a single proc call with table-valued parameters can insert numerous records into one or more tables; for example, inserting a parent record into TableA (header) and several related child records into TableB (details). This has great potential when used with .NET, i.e. a web service that sends sales data to SQL Server.

In 2005, this can be accomplished by using XML and temp tables. My hope is this new feature will outperform the XML method. In my next post, I'll follow up with a performance comparison to see if table-valued parameters live up to the hype.

In the mean-time, let's take a look at how we would actually execute this in 2008.

NOTE: This is pseudo-code, so for clarity's sake, essentials like error handling are absent.

/* Create some tables to work with */
CREATE TABLE dbo.orders
(
      order_id      INT IDENTITY(1,1)   Not Null
    , orderDate     DATE                Not Null
    , customer_id   INT                 Not Null
 
    CONSTRAINT PK_orders
        PRIMARY KEY CLUSTERED(order_id)
);
 
CREATE TABLE dbo.orderDetails
(
      orderDetail_id    INT IDENTITY(1,1)   Not Null
    , order_id          INT                 Not Null
    , lineItem          INT                 Not Null
    , product_id        INT                 Not Null
 
    CONSTRAINT PK_orderDetails
        PRIMARY KEY CLUSTERED(orderDetail_id)
 
    CONSTRAINT FK_orderDetails_orderID
        FOREIGN KEY(order_id)
        REFERENCES dbo.orders(order_id)
);
 
 
/* Create our new table types */
CREATE TYPE dbo.orderTable AS TABLE 
( 
      orderDate     DATE
    , customer_id   INT
);
GO
 
CREATE TYPE dbo.orderDetailTable AS TABLE 
( 
      lineItem      INT
    , product_id    INT
);
GO
 
 
/* Let's check out our new data types */
SELECT *
FROM sys.types
WHERE [name] IN ('orderTable', 'orderDetailTable');
GO
 
 
/* Create a new procedure using a table-valued parameter */
CREATE PROCEDURE dbo.insert_orderTVP_sp
      @myOrderTable orderTable READONLY
    , @myOrderDetailTable orderDetailTable READONLY
AS
BEGIN
 
    SET NOCOUNT ON;
 
    DECLARE @myOrderID INT;
 
    INSERT INTO dbo.orders
    SELECT orderDate
        , customer_id
    FROM @myOrderTable;
 
    SET @myOrderID = SCOPE_IDENTITY();
 
    INSERT INTO dbo.orderDetails
    SELECT @myOrderID
        , lineItem
        , product_id
    FROM @myOrderDetailTable;
 
    SET NOCOUNT OFF;
 
END
GO
 
 
/* Call our new proc! */
DECLARE @myTableHeaderData AS orderTable
    , @myTableDetailData AS orderDetailTable;
 
INSERT INTO @myTableHeaderData
(orderDate, customer_id)
SELECT GETDATE(), 101;
 
INSERT INTO @myTableDetailData
(lineItem, product_id)
SELECT 10, 123 UNION ALL
SELECT 20, 456 UNION ALL
SELECT 30, 789;
 
EXECUTE dbo.insert_orderTVP_sp 
      @myTableHeaderData
    , @myTableDetailData;
 
 
/* Check our data */
SELECT * FROM dbo.orders;
SELECT * FROM dbo.orderDetails;
 
 
/* Clean up our mess */
DROP PROCEDURE insert_orderTVP_sp;
DROP TABLE dbo.orderDetails;
DROP TABLE dbo.orders;
DROP TYPE orderTable;
DROP TYPE orderDetailTable;
Tagged as: , No Comments
8Nov/080

Large Updates on Replicated Tables

Late last night, I executed a 70mm update on a replicated table. This was a somewhat low priority update, so the primary goal (aside from the data change) was to avoid any issues on the publishing and subscribing servers, including replication latency errors. I have performed many large updates in the past, but this was the first on a replicated table.

To minimize impact, one of our system DBA's suggested the use of a replicated stored procedure. Basically, instead of replicating each of the 70mm updates as a singleton transaction, the replicated stored procedure is called on the subscribing server, which then performs the bulk update locally. This was my first time using it and it worked beautifully.

Another of my colleagues, Jeff M., suggested the use of a control table. Normally, I would just output the last affected ID and update the script manually. However, this also worked so well that it will be adopted in all future update scripts.

Using the following pseudo-script and a replicated stored procedure, I was able to execute the update on 70mm records in 11.5 hours with *zero* impact on the servers and replication. I could've probably increased the batch size and reduced the execution time even further, but as I mentioned, this was a low priority update, so there was no need to push it.

This process should work equally well on non-replicated updates; merely replace the Execute statement with the actual update.

/************ Chunked Update Script with Control Table ************/
 
/* --------------------- Preparation Script --------------------- */
 
/* Note: Execute this section in a separate query window */
 
USE yourDatabase;
Go
 
SET NOCOUNT ON;
 
/* Create a control table to facilitate tweaking of parameters */
CREATE TABLE dbo.scratch_largeUpdate_control
(
      sizeOfBatch       INT
    , waitForDelay      CHAR(8)
    , minRecordToUpdate INT 
    , maxRecordToUpdate INT
);
 
/* Create your control data; you only want 1 row in this table */
INSERT INTO dbo.scratch_largeUpdate_control 
(sizeOfBatch, waitForDelay, minRecordToUpdate, maxRecordToUpdate)
SELECT 10000, '00:00:05', 40297132, 107459380;
 
/* Update Script */
UPDATE dbo.scratch_largeUpdate_control
SET sizeOfBatch  = 100000
  , waitForDelay = '00:00:30';
 
 
/* ------------------------ Update Script ------------------------ */
USE yourDatabase;
Go
 
SET NOCOUNT ON;
 
DECLARE 
      @batchSize        INT
    , @minID            INT
    , @maxID            INT
    , @procMinID        INT
    , @procMaxID        INT
    , @delay            CHAR(8)
    , @statusMsg        VARCHAR(1000);
 
BEGIN Try
 
    IF @@SERVERNAME Not In ('PRODSERVER')
        RAISERROR('Sorry, this cannot be executed here!', 16, 1);
 
    IF Not Exists(
            SELECT OBJECT_ID 
            FROM sys.objects 
            WHERE [name] = 'scratch_largeUpdate_control' 
            And type = 'U' )
        RAISERROR ('ERROR: Control table does not exist!', 16, 1)
            WITH NoWait;
    ELSE
        SELECT 
              @minID        = minRecordToUpdate 
            , @maxID        = maxRecordToUpdate 
            , @batchSize    = sizeOfBatch
            , @delay        = waitForDelay
        FROM dbo.scratch_largeUpdate_control WITH (NoLock);
 
    SET @statusMsg = 'Beginning update; batch size of ' 
        + CAST(@batchSize AS VARCHAR(10)) + ', delay of ' 
        + @delay + ' defined.  Estimate ' 
        + CAST((((@maxID - @minID) / @batchSize) + 1) AS VARCHAR(10)) 
        + ' iterations to be performed.'
 
    RAISERROR (@statusMsg, 10, 1) WITH NoWait;
 
    WHILE @minID < @maxID
    BEGIN
 
        SELECT @procMinID = @minID
            , @procMaxID = (@minID + (@batchSize - 1));
 
        /* Execute actual update code here 
           OR 
           Call a replicated stored procedure, i.e. */
        EXECUTE dbo.myReplicatedUpdateProc 
              @minRecordID = @procMinID
            , @maxRecordID = @procMaxID;
 
        SET @statusMsg = 
            'Updating records ' + CAST(@minID AS VARCHAR(10)) 
            + ' through ' + CAST((@minID + (@batchSize - 1)) 
            AS VARCHAR(10)) + '...';
 
        RAISERROR (@statusMsg, 10, 1) WITH NoWait;
 
        /* Update our control table with the last successfully
           updated record ID.  In the event of an error,
           we can start from here. */
        UPDATE dbo.scratch_largeUpdate_control 
        SET minRecordToUpdate = @minID + @batchSize;
 
        SELECT @minID = @minID + @batchSize; 
        WAITFOR Delay @delay; -- breather for the server
 
        /* Check to see if our control values have changed */
        IF Not Exists(
            SELECT * 
            FROM dbo.scratch_largeUpdate_control WITH (NoLock) 
            WHERE @batchSize = sizeOfBatch And @delay = waitForDelay)
        BEGIN
 
            /* There was a change, so grab our new values */
            SELECT @batchSize = sizeOfBatch
                 , @delay = waitForDelay
            FROM dbo.scratch_largeUpdate_control WITH (NoLock)
 
            /* Print a status message with the new values */
            SET @statusMsg = 'Parameters changed:  batch size = ' 
                + CAST(@batchSize AS VARCHAR(10)) 
                + ', delay = ' + @delay;
 
            RAISERROR (@statusMsg, 10, 1) WITH NoWait;
 
        END
    END
 
    RAISERROR ('Success!', 10, 1) WITH NoWait;
 
END Try
/* Handle your errors */
BEGIN Catch
 
        SET @statusMsg = 'An error has occurred and the last '
                         + 'transaction has been rolled back. '
                         + 'Last record successfully updated was '
                         + 'record_id = ' 
                         + CAST((@minID + (@batchSize - 1)) 
                            AS VARCHAR(10));
 
        RAISERROR (@statusMsg, 16, 1) WITH NoWait;
 
        /* Return the error message */
        SELECT Error_Number()
            , Error_Procedure()
		    , DB_NAME()
		    , Error_Line()
		    , Error_Message()
		    , Error_Severity()
		    , Error_State();
 
END Catch;
 
/* -------------------------- Clean-Up ----------------------------
Drop Table dbo.scratch_largeUpdate_control;
----------------------------------------------------------------- */
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