Index Defrag Script Updates – Beta Testers Needed
January 26, 2010 by Michelle Ufford · 4 Comments
Filed under: Miscellaneous, Performance & Tuning, SQL 2008, Syndication, T-SQL Scripts
Filed under: Miscellaneous, Performance & Tuning, SQL 2008, Syndication, T-SQL Scripts
Update: Wow! I’ve received a ton of responses to my request for beta testers. Thank you all! The SQL Community is really amazing. I’ll hopefully have the new version online in just a few days. 
Over the last few months, I’ve received many great comments and suggestions regarding my Index Defrag Script v3.0. I’ve just recently had time to implement most of these suggestions, plus some other things that I thought would be useful.
Here’s some of what you can look forward to shortly:
- Probably the single most requested feature, the new version of the script allows you to set a time limit for index defrags.
- There’s now a static table for managing the status of index defrags. This way, when your time limit is reached, you can pick up where you left off the next day, without the need to rescan indexes.
- There’s now an option to prioritize defrags by range scan counts, fragmentation level, or page counts.
- For those using partitioning, there is now an option to exclude the right-most populated partition from defrags (in theory, the one you’re writing to in a sliding-window scenario).
- Options such as page count limits and SORT_IN_TEMPDB are now parameterized.
- I’ve enhanced error logging.
- … and more!
Right now, I’m looking for a few folks who are willing to beta test the script. If you’re interested, please send me an e-mail at michelle at sqlfool dot com with the editions of SQL Server you can test this on (i.e. 2005 Standard, 2008 Enterprise, etc.).
Thank you!
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!
Index Defrag Script, v3.0
June 23, 2009 by Michelle Ufford · 89 Comments
Filed under: Performance & Tuning, SQL 2008, Syndication, T-SQL Scripts
Filed under: Performance & Tuning, SQL 2008, Syndication, T-SQL Scripts
I’ve just completed the latest version of my index defrag script! Here’s a brief list of the updates:
- Fixed a bug with the LOB logic. In the previous version, after a LOB was encountered, all subsequent indexes would be reorganized.
- Added support for stat rebuilds after the index defrag is complete (@rebuildStats)
- Added an exclusion list table (dba_indexDefragExclusion) to support index scheduling
- Modified logging to show which defrags are “in progress”; added columns to dba_indexDefragLog
- Added support for the defrag of the model and msdb databases
- Added @scanMode as a configurable parameter
So what can this index defrag script do? Well, for starters, you can:
- Schedule it to run with the default settings; it works “right out of the box” with no additional configuration necessary
- Run this one script from a centralized database for all databases on a server
- Run this script for a specific database or table
- Configure custom threshold limits and the point at which a rebuild should be performed (instead of a reorganize)
- Defrag individual partitions
- Log its actions and the duration of the defrag
- Run in “commands only” mode (@executeSQL = 0, @printCommands = 1)
- Customize performance parameters such as @maxDopRestriction and @defragDelay to minimize impact on the server
- Schedule specific indexes to only be defragged on weekends, or every other day
To use this last option, you need to add a record to the dba_indexDefragExclusion table. I think all of the columns are pretty self-explanatory except the [exclusionMask] column. The way this works is each day of the week is assigned a value:
1=Sunday, 2=Monday, 4=Tuesday, 8=Wednesday, 16=Thursday, 32=Friday, 64=Saturday
Take a SUM of the values for the days that you want excluded. So if you want an index to only be defragged on weekends, you would add up Monday through Friday (2+4+8+16+32) and use a value of 62 for the exclusionMask column. For a little more information on how this works, check out my blog post on Bitwise Operations.
Please note: if you don’t insert any records into the dba_indexDefragExclusion table, by default all indexes will be defragged every run-time if they exceed the specified thresholds. This is normal behavior and may be perfectly fine in your environment. However, if the dba_indexDefragExclusion table does not exist, the script will fail.
I try to document each parameter within the code, so check the comments section in the script for a full list of parameters and what they do.
Special thanks to everyone who helped beta test this script!
Without further ado, the script:
/* Drop Table Scripts: Drop Table dbo.dba_indexDefragLog; Drop Table dbo.dba_indexDefragExclusion; */ IF Not Exists(SELECT [OBJECT_ID] FROM sys.tables WHERE [name] In (N'dba_indexDefragLog', 'dba_indexDefragExclusion')) BEGIN 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 CONSTRAINT PK_indexDefragLog 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 PRIMARY KEY CLUSTERED (databaseID, objectID, indexID) ); PRINT 'dba_indexDefragExclusion Table Created'; END ELSE RAISERROR('One or more tables already exist. Please drop or rename before proceeding.', 16, 0); 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 = 5.0 /* 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 */ , @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 */ , @scanMode VARCHAR(10) = N'LIMITED' /* Options are LIMITED, SAMPLED, and DETAILED */ , @onlineRebuild BIT = 1 /* 1 = online rebuild; 0 = offline rebuild; only in Enterprise */ , @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 */ , @rebuildStats BIT = 1 /* option to rebuild stats after completed index defrags */ AS /********************************************************************************* Name: dba_indexDefrag_sp Author: Michelle Ufford, http://sqlfool.com Purpose: Defrags all indexes for the current database Notes: CAUTION: TRANSACTION LOG SIZE SHOULD BE MONITORED CLOSELY WHEN DEFRAGMENTING. @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 @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. @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. @onlineRebuild 1 = online rebuild; 0 = offline rebuild @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 @rebuildStats Affects only statistics that need to be rebuilt 1 = rebuild stats 0 = do not rebuild stats Called by: SQL Agent Job or DBA 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) ********************************************************************************* Exec dbo.dba_indexDefrag_sp @executeSQL = 0 , @printCommands = 1 , @debugMode = 1 , @printFragmentation = 1; *********************************************************************************/ SET NOCOUNT ON; SET XACT_Abort ON; SET Ansi_Padding ON; SET Ansi_Warnings ON; SET ArithAbort ON; SET Concat_Null_Yields_Null ON; SET Numeric_RoundAbort OFF; SET Quoted_Identifier ON; BEGIN 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 VARCHAR(128) , @updateSQL NVARCHAR(4000) , @partitionSQL NVARCHAR(4000) , @partitionSQL_Param NVARCHAR(1000) , @LOB_SQL NVARCHAR(4000) , @LOB_SQL_Param NVARCHAR(1000) , @rebuildStatsID INT , @rebuildStatsSQL NVARCHAR(1000) , @indexDefrag_id INT; /* Create our temporary tables */ CREATE TABLE #indexDefragList ( databaseID INT , databaseName NVARCHAR(128) , objectID INT , indexID INT , partitionNumber SMALLINT , fragmentation FLOAT , page_count INT , defragStatus BIT , schemaName NVARCHAR(128) Null , objectName NVARCHAR(128) Null , indexName NVARCHAR(128) Null ); CREATE TABLE #databaseList ( databaseID INT , databaseName VARCHAR(128) , scanStatus BIT , statsStatus BIT ); CREATE TABLE #processor ( [INDEX] INT , Name VARCHAR(128) , Internal_Value INT , Character_Value INT ); IF @debugMode = 1 RAISERROR('Beginning validation...', 0, 42) WITH NoWait; /* 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'; IF @scanMode Not In ('LIMITED', 'SAMPLED', 'DETAILED') SET @scanMode = 'LIMITED'; /* 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 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 , 0 -- statistics not yet updated FROM sys.databases WHERE name = IsNull(@DATABASE, name) And [name] Not In ('master', 'tempdb')-- exclude system databases And [STATE] = 0; -- state must be ONLINE 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 #indexDefragList SELECT database_id AS databaseID , QUOTENAME(DB_NAME(database_id)) AS 'databaseName' , [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 */ , Null AS 'schemaName' , Null AS 'objectName' , Null AS 'indexName' FROM sys.dm_db_index_physical_stats (@databaseID, OBJECT_ID(@tableName), Null , Null, @scanMode) WHERE avg_fragmentation_in_percent >= @minFragmentation And index_id > 0 -- ignore heaps And page_count > 8 -- ignore objects with less than 1 extent And index_level = 0 -- leaf-level nodes only, supports @scanMode OPTION (MaxDop 2); /* Keep track of which databases have already been scanned */ UPDATE #databaseList SET scanStatus = 1 WHERE databaseID = @databaseID; END CREATE CLUSTERED INDEX CIX_temp_indexDefragList ON #indexDefragList(databaseID, objectID, indexID, partitionNumber); /* Delete any indexes from our to-do that are also in our exclusion list for today */ DELETE idl FROM #indexDefragList AS idl Join dbo.dba_indexDefragExclusion AS ide ON idl.databaseID = ide.databaseID And idl.objectID = ide.objectID And idl.indexID = ide.indexID WHERE exclusionMask & POWER(2, DATEPART(weekday, GETDATE())-1) > 0; SELECT @debugMessage = 'Looping through our list... there''s ' + CAST(COUNT(*) AS VARCHAR(10)) + ' indexes to defrag!' FROM #indexDefragList; IF @debugMode = 1 RAISERROR(@debugMessage, 0, 42) WITH NoWait; /* Begin our loop for defragging */ WHILE (SELECT COUNT(*) FROM #indexDefragList WHERE defragStatus = 0) > 0 BEGIN IF @debugMode = 1 RAISERROR(' Picking an index to beat into shape...', 0, 42) WITH NoWait; /* Grab the most fragmented index first to defrag */ SELECT TOP 1 @objectID = objectID , @indexID = indexID , @databaseID = databaseID , @databaseName = databaseName , @fragmentation = fragmentation , @partitionNumber = partitionNumber , @pageCount = page_count FROM #indexDefragList WHERE defragStatus = 0 ORDER BY fragmentation DESC; IF @debugMode = 1 RAISERROR(' Looking up the specifics for our index...', 0, 42) WITH NoWait; /* Look up index information */ SELECT @updateSQL = N'Update idl Set schemaName = QuoteName(s.name) , objectName = QuoteName(o.name) , indexName = QuoteName(i.name) From #indexDefragList As idl Inner Join ' + @databaseName + '.sys.objects As o On idl.objectID = o.object_id Inner Join ' + @databaseName + '.sys.indexes As i On o.object_id = i.object_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 idl.databaseID = ' + CAST(@databaseID AS VARCHAR(10)); EXECUTE SP_EXECUTESQL @updateSQL; /* Grab our object names */ SELECT @objectName = objectName , @schemaName = schemaName , @indexName = indexName FROM #indexDefragList 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''s 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(' 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 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, rebuild it */ IF @fragmentation >= @rebuildThreshold 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 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; /* Are we executing the SQL? If so, do it */ IF @executeSQL = 1 BEGIN IF @debugMode = 1 RAISERROR(' Executing SQL statements...', 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 ) SELECT @databaseID , @databaseName , @objectID , @objectName , @indexID , @indexName , @partitionNumber , @fragmentation , @pageCount , @dateTimeStart; SET @indexDefrag_id = SCOPE_IDENTITY(); /* 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; /* 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 printing the commands */ BEGIN IF @debugMode = 1 RAISERROR(' Printing SQL statements...', 0, 42) WITH NoWait; IF @printCommands = 1 PRINT IsNull(@sqlCommand, 'error!'); END IF @debugMode = 1 RAISERROR(' Updating our index defrag status...', 0, 42) WITH NoWait; /* Update our index defrag list so we know we've finished with that index */ UPDATE #indexDefragList SET defragStatus = 1 WHERE databaseID = @databaseID And objectID = @objectID And indexID = @indexID And partitionNumber = @partitionNumber; END /* Do we want to output our fragmentation results? */ IF @printFragmentation = 1 BEGIN IF @debugMode = 1 RAISERROR(' Displaying fragmentation results...', 0, 42) WITH NoWait; SELECT databaseID , databaseName , objectID , objectName , indexID , indexName , fragmentation , page_count FROM #indexDefragList; END; /* Do we want to rebuild stats? */ IF @rebuildStats = 1 BEGIN WHILE Exists(SELECT TOP 1 * FROM #databaseList WHERE statsStatus = 0) BEGIN /* Build our SQL statement to update stats */ SELECT TOP 1 @rebuildStatsSQL = 'Use [' + databaseName + ']; ' + 'Execute sp_updatestats;' , @rebuildStatsID = databaseID FROM #databaseList WHERE statsStatus = 0; SET @debugMessage = 'Rebuilding Statistics: ' + @rebuildStatsSQL; IF @debugMode = 1 RAISERROR(@debugMessage, 0, 42) WITH NoWait; /* Execute our stats update! */ EXECUTE SP_EXECUTESQL @rebuildStatsSQL; /* Keep track of which databases have been updated */ UPDATE #databaseList SET statsStatus = 1 WHERE databaseID = @rebuildStatsID; END; END; /* When everything is said and done, make sure to get rid of our temp table */ DROP TABLE #indexDefragList; DROP TABLE #databaseList; DROP TABLE #processor; IF @debugMode = 1 RAISERROR('DONE! Thank you for taking care of your indexes! :)', 0, 42) WITH NoWait; SET NOCOUNT OFF; RETURN 0 END Go SET Quoted_Identifier OFF SET ANSI_Nulls ON Go
Automated Index Defrag Script
March 25, 2009 by Michelle Ufford · 35 Comments
Filed under: Performance & Tuning, SQL 2008, SQL Tips, T-SQL Scripts
Filed under: Performance & Tuning, SQL 2008, SQL Tips, T-SQL Scripts
Note: This script has been updated. You can find the latest version here: http://sqlfool.com/2009/06/index-defrag-script-v30/
So after much delay, here’s the latest and greatest version of my index defrag script.
A summary of the changes:
- Added support for centralized execution. Option to defrag indexes for a single database from another database, or for all non-system databases.
- Consolidated Enterprise and Standard versions of the script with new @editionCheck variable.
- Added parametrization for MaxDop restrictions during rebuilds; validates that the value does not exceed the actual number of processors on the server.
- Changed minimum fragmentation default value from 10 to 5 to match BOL recommendations.
- Limited defrags to objects with more than 8 pages.
- Added a debug option to give a little more insight into what’s happening and to assist with troubleshooting.
- Updated logic for handling partitions and LOBs.
And a couple of notes and explanations:
Don’t you know you can just pass NULL to sys.dm_db_index_physical_stats for the DatabaseID?
Yes, I realize you can do this. But I don’t want to defrag the system databases, i.e. tempdb, so I opted to handle it this way instead.
How long will this take?
It depends. I don’t necessarily recommend running it without specifying a database; at least, not unmonitored. You *can* do that, but it could take a while. For example, to run sys.dm_db_index_physical_stats for all databases and tables, totaling 2TB, took me 4.5 hours; that doesn’t even count the actual defrags.
Where should I put this?
It’s up to you. If you have a database for items like centralized maintenance or scratch tables, that may be a good place for it. If you prefer, you could also put this in each individual database and call it locally, too. I would not put this in the master or msdb databases.
This is pretty close to a complete rewrite, so please let me know if you encounter any bugs. And now… the code!
IF Not Exists(SELECT [OBJECT_ID] FROM sys.tables WHERE name = N'dba_indexDefragLog') BEGIN -- Drop Table dbo.dba_indexDefragLog 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 , durationSeconds INT Not Null CONSTRAINT PK_indexDefragLog PRIMARY KEY CLUSTERED (indexDefrag_id) ) PRINT 'dba_indexDefragLog Table Created'; END 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 = 5.0 /* 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 */ , @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 */ , @onlineRebuild BIT = 1 /* 1 = online rebuild; 0 = offline rebuild; only in Enterprise */ , @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 all indexes for one or more databases Notes: CAUTION: TRANSACTION LOG SIZE MUST BE MONITORED CLOSELY WHEN DEFRAGMENTING. @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 @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. @onlineRebuild 1 = online rebuild; 0 = offline rebuild @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 Date Initials Description ---------------------------------------------------------------------------- 2008-10-27 MFU Initial Release for public consumption 2008-11-17 MFU Added page-count to log table , added @printFragmentation option 2009-03-17 MFU Provided support for centralized execution, , consolidated Enterprise & Standard versions , added @debugMode, @maxDopRestriction , modified LOB and partition logic ********************************************************************************* Exec dbo.dba_indexDefrag_sp @executeSQL = 0 , @minFragmentation = 80 , @printCommands = 1 , @debugMode = 1 , @printFragmentation = 1 , @database = 'AdventureWorks' , @tableName = 'AdventureWorks.Sales.SalesOrderDetail'; *********************************************************************************/ SET NOCOUNT ON; SET XACT_Abort ON; SET Quoted_Identifier ON; BEGIN IF @debugMode = 1 RAISERROR('Dusting off the spiderwebs 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 , @partitions SMALLINT , @fragmentation FLOAT , @pageCount INT , @sqlCommand NVARCHAR(4000) , @rebuildCommand NVARCHAR(200) , @dateTimeStart DATETIME , @dateTimeEnd DATETIME , @containsLOB BIT , @editionCheck BIT , @debugMessage VARCHAR(128) , @updateSQL NVARCHAR(4000) , @partitionSQL NVARCHAR(4000) , @partitionSQL_Param NVARCHAR(1000) , @LOB_SQL NVARCHAR(4000) , @LOB_SQL_Param NVARCHAR(1000); /* Create our temporary tables */ CREATE TABLE #indexDefragList ( databaseID INT , databaseName NVARCHAR(128) , objectID INT , indexID INT , partitionNumber SMALLINT , fragmentation FLOAT , page_count INT , defragStatus BIT , schemaName NVARCHAR(128) Null , objectName NVARCHAR(128) Null , indexName NVARCHAR(128) Null ); CREATE TABLE #databaseList ( databaseID INT , databaseName VARCHAR(128) ); CREATE TABLE #processor ( [INDEX] INT , Name VARCHAR(128) , Internal_Value INT , Character_Value INT ); IF @debugMode = 1 RAISERROR('Beginning validation...', 0, 42) WITH NoWait; /* Just a little validation... */ IF @minFragmentation Not Between 0.00 And 100.0 SET @minFragmentation = 5.0; 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'; /* 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 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 FROM sys.databases WHERE name = IsNull(@DATABASE, name) And database_id > 4 -- exclude system databases And [STATE] = 0; -- state must be ONLINE 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) > 0 BEGIN SELECT TOP 1 @databaseID = databaseID FROM #databaseList; 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 #indexDefragList SELECT database_id AS databaseID , QUOTENAME(DB_NAME(database_id)) AS 'databaseName' , [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 */ , Null AS 'schemaName' , Null AS 'objectName' , Null AS 'indexName' FROM sys.dm_db_index_physical_stats (@databaseID, OBJECT_ID(@tableName), Null , Null, N'Limited') WHERE avg_fragmentation_in_percent >= @minFragmentation And index_id > 0 -- ignore heaps And page_count > 8 -- ignore objects with less than 1 extent OPTION (MaxDop 1); DELETE FROM #databaseList WHERE databaseID = @databaseID; END CREATE CLUSTERED INDEX CIX_temp_indexDefragList ON #indexDefragList(databaseID, objectID, indexID, partitionNumber); SELECT @debugMessage = 'Looping through our list... there''s ' + CAST(COUNT(*) AS VARCHAR(10)) + ' indexes to defrag!' FROM #indexDefragList; IF @debugMode = 1 RAISERROR(@debugMessage, 0, 42) WITH NoWait; /* Begin our loop for defragging */ WHILE (SELECT COUNT(*) FROM #indexDefragList WHERE defragStatus = 0) > 0 BEGIN IF @debugMode = 1 RAISERROR(' Picking an index to beat into shape...', 0, 42) WITH NoWait; /* Grab the most fragmented index first to defrag */ SELECT TOP 1 @objectID = objectID , @indexID = indexID , @databaseID = databaseID , @databaseName = databaseName , @fragmentation = fragmentation , @partitionNumber = partitionNumber , @pageCount = page_count FROM #indexDefragList WHERE defragStatus = 0 ORDER BY fragmentation DESC; IF @debugMode = 1 RAISERROR(' Looking up the specifics for our index...', 0, 42) WITH NoWait; /* Look up index information */ SELECT @updateSQL = N'Update idl Set schemaName = QuoteName(s.name) , objectName = QuoteName(o.name) , indexName = QuoteName(i.name) From #indexDefragList As idl Inner Join ' + @databaseName + '.sys.objects As o On idl.objectID = o.object_id Inner Join ' + @databaseName + '.sys.indexes As i On o.object_id = i.object_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 idl.databaseID = ' + CAST(@databaseID AS VARCHAR(10)); EXECUTE SP_EXECUTESQL @updateSQL; /* Grab our object names */ SELECT @objectName = objectName , @schemaName = schemaName , @indexName = indexName FROM #indexDefragList 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''s any LOBs to be handled...', 0, 42) WITH NoWait; /* Determine if the table contains LOBs */ SELECT @LOB_SQL = ' Select Top 1 @containsLOB_OUT = column_id 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(' 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 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, rebuild it */ IF @fragmentation >= @rebuildThreshold 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 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; /* Are we executing the SQL? If so, do it */ IF @executeSQL = 1 BEGIN IF @debugMode = 1 RAISERROR(' Executing SQL statements...', 0, 42) WITH NoWait; /* Grab the time for logging purposes */ SET @dateTimeStart = GETDATE(); EXECUTE SP_EXECUTESQL @sqlCommand; SET @dateTimeEnd = GETDATE(); /* Log our actions */ INSERT INTO dbo.dba_indexDefragLog ( databaseID , databaseName , objectID , objectName , indexID , indexName , partitionNumber , fragmentation , page_count , dateTimeStart , durationSeconds ) SELECT @databaseID , @databaseName , @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 printing the commands */ BEGIN IF @debugMode = 1 RAISERROR(' Printing SQL statements...', 0, 42) WITH NoWait; IF @printCommands = 1 PRINT IsNull(@sqlCommand, 'error!'); END IF @debugMode = 1 RAISERROR(' Updating our index defrag status...', 0, 42) WITH NoWait; /* Update our index defrag list so we know we've finished with that index */ UPDATE #indexDefragList SET defragStatus = 1 WHERE databaseID = @databaseID And objectID = @objectID And indexID = @indexID And partitionNumber = @partitionNumber; END /* Do we want to output our fragmentation results? */ IF @printFragmentation = 1 BEGIN IF @debugMode = 1 RAISERROR(' Displaying fragmentation results...', 0, 42) WITH NoWait; SELECT databaseID , databaseName , objectID , objectName , indexID , indexName , fragmentation , page_count FROM #indexDefragList; END; /* When everything is said and done, make sure to get rid of our temp table */ DROP TABLE #indexDefragList; DROP TABLE #databaseList; DROP TABLE #processor; IF @debugMode = 1 RAISERROR('DONE! Thank you for taking care of your indexes! :)', 0, 42) WITH NoWait; SET NOCOUNT OFF; RETURN 0 END Go
Thanks to my beta testers, @scoinva, @davidmtate, @jdanton, and @SuperCoolMoss!
Special thanks to SCM for keeping on me to finish this.
Happy Defragging!
Michelle
Source: http://sqlfool.com/2009/03/automated-index-defrag-script/
Updated Index Defrag Script (2005, 2008)
November 17, 2008 by Michelle Ufford · 18 Comments
Filed under: Performance & Tuning, SQL 2008, T-SQL Scripts
Filed under: Performance & Tuning, SQL 2008, T-SQL Scripts
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.
Index Defrag Script
Previously I posted that it’s important to keep your indexes in shape with weekly or (preferably) nightly defrags. Below is a script I use to execute nightly defrags in SQL 2005 Enterprise. I can’t claim complete credit… I believe this is a script I originally found on Microsoft and heavily modified to meet my needs.
You may want to modify the script if you’re doing much with XML or LOB’s. Also keep in mind that this is hitting the sys.dm_db_index_physical_stats table to view fragmentation information, which can be resource intensive.
If you’re not familiar with index defragmentation, check out “Alter Index” on Books Online.
IF Not Exists(SELECT OBJECT_ID FROM sys.tables WHERE [name] = N'dba_indexDefragLog') BEGIN 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 , dateTimeStart DATETIME not null , durationSeconds INT not null CONSTRAINT PK_indexDefragLog PRIMARY KEY CLUSTERED (indexDefrag_id) ); PRINT 'dba_indexDefragLog Table Created'; END 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 */ , @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: CAUTION: Monitor transaction log when 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 @defragDelay time to wait between defrag commands; gives the server a little time to catch up Called by: SQL Agent Job or DBA Date Initials Description ------------------------------------------------------------------- 2008-10-27 MFU Initial Release *********************************************************************** Exec dbo.dba_indexDefrag_sp @executeSQL = 0 , @printCommands = 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 , @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 , 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 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 , dateTimeStart , durationSeconds ) SELECT @objectID , @objectName , @indexID , @indexName , @partitionNumber , @fragmentation , @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 /* When everything is done, make sure to get rid of our temp table */ DROP TABLE #indexDefragList; SET NOCOUNT OFF; RETURN 0 END Go SET Quoted_Identifier OFF SET ANSI_Nulls ON Go
20081117 UPDATE: Check out my Updated Index Defrag Script for SQL 2005 and 2008.
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