T-SQL Script for Estimating Compression Savings

A couple of weeks ago, I was working on a Microsoft PDW proof-of-concept (POC) and had to measure compression ratios. In order to do this, I fired up SSMS and wrote a little script. The script will iterate through all tables in a database and run the sp_estimate_data_compression_savings stored procedure. This will only work in SQL Server 2008+ versions running Enterprise edition.

If you’re not familiar with this stored procedure, it basically will tell you what effect PAGE or ROW compression will have on your table/index/partition, etc. There are pro’s and con’s with compression. What I’ve tended to see is that compression has very positive results on space, IO, and query duration, with a negative impact on CPU and write speed. Like most things, it’s a trade-off and the results will vary by environment, so I recommend you do some testing before you apply compression to all tables. I tend to use compression mostly for my historical tables and partitions and leave my recent data uncompressed. And, back to the script, I use this stored procedure to estimate the impact of compression and to determine whether to use PAGE or ROW compression. PAGE is a higher level of compression, which means it’s also more expensive in terms of CPU, so if the difference between the two results is negligible, I’m more apt to just use ROW compression.

Now that my impromptu compression discussion is done, let’s get to the actual script. One final word of caution, however. This is an IO intensive process, so you may want to run it after peak business hours.

SET NOCOUNT ON;
 
DECLARE @printOnly  BIT = 0 -- change to 1 if you don't want to execute, just print commands
    , @tableName    VARCHAR(256)
    , @schemaName   VARCHAR(100)
    , @sqlStatement NVARCHAR(1000)
    , @tableCount   INT
    , @statusMsg    VARCHAR(1000);
 
IF EXISTS(SELECT * FROM tempdb.sys.tables WHERE name LIKE '%#tables%')
    DROP TABLE #tables; 
 
CREATE TABLE #tables
(
      database_name     sysname
    , schemaName        sysname NULL
    , tableName         sysname NULL
    , processed         bit
);
 
IF EXISTS(SELECT * FROM tempdb.sys.tables WHERE name LIKE '%#compression%')
    DROP TABLE #compressionResults;
 
IF NOT EXISTS(SELECT * FROM tempdb.sys.tables WHERE name LIKE '%#compression%')
BEGIN 
 
    CREATE TABLE #compressionResults
    (
          objectName                    varchar(100)
        , schemaName                    varchar(50)
        , index_id                      int
        , partition_number              int
        , size_current_compression      bigint
        , size_requested_compression    bigint
        , sample_current_compression    bigint
        , sample_requested_compression  bigint
    );
 
END;
 
INSERT INTO #tables
SELECT DB_NAME()
    , SCHEMA_NAME([schema_id])
    , name
    , 0 -- unprocessed
FROM sys.tables;
 
SELECT @tableCount = COUNT(*) FROM #tables;
 
WHILE EXISTS(SELECT * FROM #tables WHERE processed = 0)
BEGIN
 
    SELECT TOP 1 @tableName = tableName
        , @schemaName = schemaName
    FROM #tables WHERE processed = 0;
 
    SELECT @statusMsg = 'Working on ' + CAST(((@tableCount - COUNT(*)) + 1) AS VARCHAR(10)) 
        + ' of ' + CAST(@tableCount AS VARCHAR(10))
    FROM #tables
    WHERE processed = 0;
 
    RAISERROR(@statusMsg, 0, 42) WITH NOWAIT;
 
    SET @sqlStatement = 'EXECUTE sp_estimate_data_compression_savings ''' 
                        + @schemaName + ''', ''' + @tableName + ''', NULL, NULL, ''PAGE'';' -- ROW, PAGE, or NONE
 
    IF @printOnly = 1
    BEGIN 
 
        SELECT @sqlStatement;
 
    END
    ELSE
    BEGIN
 
        INSERT INTO #compressionResults
        EXECUTE sp_executesql @sqlStatement;
 
    END;
 
    UPDATE #tables
    SET processed = 1
    WHERE tableName = @tableName
        AND schemaName = @schemaName;
 
END;
 
SELECT * 
FROM #compressionResults;

String Parsing Function

This handy little script parses a string and returns the results as a table. I know there are a ton of string parsing functions out there, but I thought I’d add to the list. ;)

The basic logic of it (using a CTE) is derived from a forum post I found years ago. The table-valued UDF, delimiter, etc. is all stuff that I added. So thus, while I can not claim complete credit, I still thought it’d be worthwhile to share. Plus this will be used in another script I will be posting soon. :)

/* Let's create our parsing function... */
CREATE FUNCTION dbo.dba_parseString_udf
(
          @stringToParse VARCHAR(8000)  
        , @delimiter     CHAR(1)
)
RETURNS @parsedString TABLE (stringValue VARCHAR(128))
AS
/*********************************************************************************
    Name:       dba_parseString_udf
 
    Author:     Michelle Ufford, http://sqlfool.com
 
    Purpose:    This function parses string input using a variable delimiter.
 
    Notes:      Two common delimiter values are space (' ') and comma (',')
 
    Date        Initials    Description
    ----------------------------------------------------------------------------
    2011-05-20  MFU         Initial Release
*********************************************************************************
Usage: 		
    SELECT *
	FROM dba_parseString_udf(<string>, <delimiter>);
 
Test Cases:
 
    1.  multiple strings separated by space
        SELECT * FROM dbo.dba_parseString_udf('  aaa  bbb  ccc ', ' ');
 
    2.  multiple strings separated by comma
        SELECT * FROM dbo.dba_parseString_udf(',aaa,bbb,,,ccc,', ',');
*********************************************************************************/
BEGIN
 
    /* Declare variables */
    DECLARE @trimmedString  VARCHAR(8000);
 
    /* We need to trim our string input in case the user entered extra spaces */
    SET @trimmedString = LTRIM(RTRIM(@stringToParse));
 
    /* Let's create a recursive CTE to break down our string for us */
    WITH parseCTE (StartPos, EndPos)
    AS
    (
        SELECT 1 AS StartPos
            , CHARINDEX(@delimiter, @trimmedString + @delimiter) AS EndPos
        UNION ALL
        SELECT EndPos + 1 AS StartPos
            , CharIndex(@delimiter, @trimmedString + @delimiter , EndPos + 1) AS EndPos
        FROM parseCTE
        WHERE CHARINDEX(@delimiter, @trimmedString + @delimiter, EndPos + 1) <> 0
    )
 
    /* Let's take the results and stick it in a table */  
    INSERT INTO @parsedString
    SELECT SUBSTRING(@trimmedString, StartPos, EndPos - StartPos)
    FROM parseCTE
    WHERE LEN(LTRIM(RTRIM(SUBSTRING(@trimmedString, StartPos, EndPos - StartPos)))) > 0
    OPTION (MaxRecursion 8000);
 
    RETURN;   
END

Identity Columns: Are You Nearing The Limits?

I use identity columns frequently. After all, identity columns make great clustering keys. But it’s important when using identity columns to check on the amount of values you have left before you reach the limit of your data type. An identity column has a fixed amount of values it can use based upon whether you specified tinyint, smallint, int, or bigint when you defined the column. If you reach this limit, your inserts will blow up and cause a Chernobyl-like SQL meltdown will begin to fail. I just finished an audit of my tables and thought I’d share the script. I would like to warn that this script is *not* perfect… namely, it doesn’t handle negative integer values very elegantly. It also doesn’t know if you started your seed at zero, approached your max positive limit, then reseeded to the negative limit (see my “quick and dirty fix” tip at the end of this article).

/* Define how close we are to the value limit
   before we start throwing up the red flag.
   The higher the value, the closer to the limit. */
Declare @threshold decimal(3,2) = .85;
 
/* Create a temp table */
Create Table #identityStatus
(
      database_name     varchar(128)
    , table_name        varchar(128)
    , column_name       varchar(128)
    , data_type         varchar(128)
    , last_value        bigint
    , max_value         bigint
);
 
/* Use an undocumented command to run a SQL statement
   in each database on a server */
Execute sp_msforeachdb '
    Use [?];
    Insert Into #identityStatus
    Select ''?'' As [database_name]
        , Object_Name(id.object_id, DB_ID(''?'')) As [table_name]
        , id.name As [column_name]
        , t.name As [data_type]
        , Cast(id.last_value As bigint) As [last_value]
        , Case 
            When t.name = ''tinyint''   Then 255 
            When t.name = ''smallint''  Then 32767 
            When t.name = ''int''       Then 2147483647 
            When t.name = ''bigint''    Then 9223372036854775807
          End As [max_value]
    From sys.identity_columns As id
    Join sys.types As t
        On id.system_type_id = t.system_type_id
    Where id.last_value Is Not Null';
 
/* Retrieve our results and format it all prettily */
Select database_name
    , table_name
    , column_name
    , data_type
    , last_value
    , Case 
        When last_value < 0 Then 100
        Else (1 - Cast(last_value As float(4)) / max_value) * 100 
      End As [percentLeft]
    , Case 
        When Cast(last_value As float(4)) / max_value >= @threshold
            Then 'warning: approaching max limit'
        Else 'okay'
        End As [id_status]
From #identityStatus
Order By percentLeft;
 
/* Clean up after ourselves */
Drop Table #identityStatus;

If you find yourself quickly approaching your max limit and need to implement a quick and dirty fix, you can reseed your identity column. Of course, this only works if you started at zero instead of the actual lower, negative limit.

SQL Agent Job Script

This blog post is brought to you by the awesomeness that is the SQL Server Twitter community. Contributions were made by several awesome Tweeples, including Denny Cherry, Kendra Little, Ken Simmons, and Magnus Ahlkvist, among others.

What started this is something you’ve all probably run into at one time or another. We’re currently having some resource contention on our server when a ton of processes kickoff and overlap in the morning. Now, I have a script that I’ve used in the past for monitoring SQL agent jobs, but this time I wanted to add some historical run-time information. I know the sysjobhistory table contains the information I need, but it has some… let’s say, creative ways of storing the data. Opinions on the reasons why vary:



Regardless the reason, I needed to do some conversions. Denny shared with us the msdb.dbo.agent_datetime function to convert run_date and run_time into an actual datetime value. I have to say, this certainly cleans up the code quite a bit! Then Magnus shared a method to convert run_duration into seconds, which he modified from a script on SQLServerCentral. I was able to use these two tidbits to update my old script. You can now run this script to get back a list of all enabled procs, a script that will disable them, a breakdown of the schedule, and a historical run-time average.

/*  How many days do you want to include in your run-time average?
    Recent values tend to be more useful. */
Declare @daysToAverage smallint = 30;
 
Declare @avgRunTime Table
(
      job_id      uniqueidentifier
    , avgRunTime  int
);
 
/* We need to parse the schedule into something we can understand */
Declare @weekDay Table (
      mask       int
    , maskValue  varchar(32)
);
 
Insert Into @weekDay
Select 1, 'Sunday'  Union All
Select 2, 'Monday'  Union All
Select 4, 'Tuesday'  Union All
Select 8, 'Wednesday'  Union All
Select 16, 'Thursday'  Union All
Select 32, 'Friday'  Union All
Select 64, 'Saturday';
 
/* First, let's get our run-time average */
Insert Into @avgRunTime
Select job_id
    , Avg((run_duration/10000) * 3600 + (run_duration/100%100)*60 + run_duration%100) As 'avgRunTime' /* convert HHMMSS to seconds */
From msdb.dbo.sysjobhistory
Where step_id = 0 -- only grab our total run-time
    And run_status = 1 -- only grab successful executions
    And msdb.dbo.agent_datetime(run_date, run_time) >= DateAdd(day, -@daysToAverage, GetDate())
Group By job_id;
 
/* Now let's get our schedule information */
With myCTE
As(
    Select sched.name As 'scheduleName'
        , sched.schedule_id
        , jobsched.job_id
        , Case When sched.freq_type = 1 Then 'Once' 
            When sched.freq_type = 4 
                And sched.freq_interval = 1 
                    Then 'Daily'
            When sched.freq_type = 4 
                Then 'Every ' + Cast(sched.freq_interval As varchar(5)) + ' days'
            When sched.freq_type = 8 Then 
                Replace( Replace( Replace(( 
                    Select maskValue 
                    From @weekDay As x 
                    Where sched.freq_interval & x.mask <> 0 
                    Order By mask For XML Raw)
                , '"/><row maskValue="', ', '), '<row maskValue="', ''), '"/>', '') 
                + Case When sched.freq_recurrence_factor <> 0 
                        And sched.freq_recurrence_factor = 1 
                            Then '; weekly' 
                    When sched.freq_recurrence_factor <> 0 Then '; every ' 
                + Cast(sched.freq_recurrence_factor As varchar(10)) + ' weeks' End
            When sched.freq_type = 16 Then 'On day ' 
                + Cast(sched.freq_interval As varchar(10)) + ' of every '
                + Cast(sched.freq_recurrence_factor As varchar(10)) + ' months' 
            When sched.freq_type = 32 Then 
                Case When sched.freq_relative_interval = 1 Then 'First'
                    When sched.freq_relative_interval = 2 Then 'Second'
                    When sched.freq_relative_interval = 4 Then 'Third'
                    When sched.freq_relative_interval = 8 Then 'Fourth'
                    When sched.freq_relative_interval = 16 Then 'Last'
                End + 
                Case When sched.freq_interval = 1 Then ' Sunday'
                    When sched.freq_interval = 2 Then ' Monday'
                    When sched.freq_interval = 3 Then ' Tuesday'
                    When sched.freq_interval = 4 Then ' Wednesday'
                    When sched.freq_interval = 5 Then ' Thursday'
                    When sched.freq_interval = 6 Then ' Friday'
                    When sched.freq_interval = 7 Then ' Saturday'
                    When sched.freq_interval = 8 Then ' Day'
                    When sched.freq_interval = 9 Then ' Weekday'
                    When sched.freq_interval = 10 Then ' Weekend'
                End
                + Case When sched.freq_recurrence_factor <> 0 
                        And sched.freq_recurrence_factor = 1 Then '; monthly'
                    When sched.freq_recurrence_factor <> 0 Then '; every ' 
                + Cast(sched.freq_recurrence_factor As varchar(10)) + ' months' End
            When sched.freq_type = 64 Then 'StartUp'
            When sched.freq_type = 128 Then 'Idle'
          End As 'frequency'
        , IsNull('Every ' + Cast(sched.freq_subday_interval As varchar(10)) + 
            Case When sched.freq_subday_type = 2 Then ' seconds'
                When sched.freq_subday_type = 4 Then ' minutes'
                When sched.freq_subday_type = 8 Then ' hours'
            End, 'Once') As 'subFrequency'
        , Replicate('0', 6 - Len(sched.active_start_time)) 
            + Cast(sched.active_start_time As varchar(6)) As 'startTime'
        , Replicate('0', 6 - Len(sched.active_end_time)) 
            + Cast(sched.active_end_time As varchar(6)) As 'endTime'
        , Replicate('0', 6 - Len(jobsched.next_run_time)) 
            + Cast(jobsched.next_run_time As varchar(6)) As 'nextRunTime'
        , Cast(jobsched.next_run_date As char(8)) As 'nextRunDate'
    From msdb.dbo.sysschedules As sched
    Join msdb.dbo.sysjobschedules As jobsched
        On sched.schedule_id = jobsched.schedule_id
    Where sched.enabled = 1
)
 
/* Finally, let's look at our actual jobs and tie it all together */
Select job.name As 'jobName'
    , sched.scheduleName
    , sched.frequency
    , sched.subFrequency
    , SubString(sched.startTime, 1, 2) + ':' 
        + SubString(sched.startTime, 3, 2) + ' - ' 
        + SubString(sched.endTime, 1, 2) + ':' 
        + SubString(sched.endTime, 3, 2) 
        As 'scheduleTime' -- HH:MM
    , SubString(sched.nextRunDate, 1, 4) + '/' 
        + SubString(sched.nextRunDate, 5, 2) + '/' 
        + SubString(sched.nextRunDate, 7, 2) + ' ' 
        + SubString(sched.nextRunTime, 1, 2) + ':' 
        + SubString(sched.nextRunTime, 3, 2) As 'nextRunDate'
      /* Note: the sysjobschedules table refreshes every 20 min, 
        so nextRunDate may be out of date */
    , 'Execute msdb.dbo.sp_update_job @job_id = ''' 
        + Cast(job.job_id As char(36)) + ''', @enabled = 0;' As 'disableScript'
    , art.avgRunTime As 'avgRunTime_inSec' -- in seconds
    , (art.avgRunTime / 60) As 'avgRunTime_inMin' -- convert to minutes
From msdb.dbo.sysjobs As job
Join myCTE As sched
    On job.job_id = sched.job_id
Left Join @avgRunTime As art
    On job.job_id = art.job_id
Where job.enabled = 1 -- do not display disabled jobs
Order By nextRunDate;

If this doesn’t do exactly what you want, check out SQLJobVis, which Ken recommended. It’s a free tool that helps visualize the job history of SQL jobs.

Rename Database Objects En Masse

Ever need to rename all objects in a database? Yeah, okay… it doesn’t happen very often, but when it does, it can be time consuming. This recently came up as something I needed to do. When you consider all the tables involved and you add in defaults, indexes, and foreign keys, well… you can imagine how the number of objects adds up quickly. After doing a few tedious renames, it occurred to me that I could write a script to generate the rename scripts for me. Work smarter, not harder, right? For anyone interested, here’s the script.

Select name
    , [object_id] 
    , Case 
        When [type] = 'U' Then 'Execute sp_rename N''' + name + ''', N''old_' + name + ''''
        When [type] IN ('D', 'PK', 'F') Then 
            'Execute sp_rename N''' + name + ''', N''old_' + name + ''', N''OBJECT'''
        End As 'renameScript'
    , Case When parent_object_id > 0 Then 0 Else 1 End As 'sortOrder'
From sys.objects
Where [type] In ('D', 'PK', 'U', 'F')
Union ALL
Select i.name
    , o.[object_id]
    , 'Execute sp_rename N''' + o.name + '.' + i.name + ''', N''old_' + i.name + ''', N''INDEX''' As 'renameScript'
    , 0 As 'sortOrder'
From sys.indexes As i
JOIN sys.objects As o
    On i.object_id = o.object_id
Where i.is_primary_key = 0 -- exclude PKs, we take care of that above
    AND i.type <> 0 -- exclude heaps
    AND o.type Not In ('S', 'IT') -- exclude system & internal tables
Order By sortOrder;

Be forewarned that I only tested this on a couple of databases, but it seemed to run without problem for tables, indexes, primary keys, defaults, and foreign keys. The sortOrder column is there only to ensure that table renames are performed last. Otherwise, your index renames would fail. This will only run on SQL Server 2005 or 2008. If you have any problems with the script, please let me know. :)

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:

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

Index Defrag Script, v4.0

UPDATE: This script has been updated. Please view the latest version at http://sqlfool.com/2011/06/index-defrag-script-v4-1/.

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:

UPDATE: This script has been updated. Please view the latest version at http://sqlfool.com/2011/06/index-defrag-script-v4-1/.

/* 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

Index Defrag Script Updates – Beta Testers Needed

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! :)

Monitoring Process for Performance Counters

Recently I needed to create a process to monitor performance counters over a short period of time. We were going to implement a change and we wanted to compare performance before and after to see if there was any impact.

To do this, I first created a couple of tables. One table is used to actually store the monitored values. The second table is used for configuration; you insert only the counters you want to monitor.

/* Create the table to store our logged perfmon counters */
Create Table dbo.dba_perfCounterMonitor
(
      capture_id    int Identity(1,1)   Not Null
    , captureDate   smalldatetime       Not Null
    , objectName    nvarchar(128)       Not Null
    , counterName   nvarchar(128)       Not Null
    , instanceName  nvarchar(128)       Not Null
    , value         float(6)            Not Null
    , valueType     nvarchar(10)        Not Null
 
    Constraint PK_dba_perfCounterMonitor
        Primary Key Clustered(capture_id)
);
 
/* Create the table that controls which counters we're going to monitor */
Create Table dbo.dba_perfCounterMonitorConfig
(
      objectName    nvarchar(128)   Not Null
    , counterName   nvarchar(128)   Not Null
    , instanceName  nvarchar(128)   Null
);

If you leave the instanceName NULL in the config table, it’ll monitor all instances. Now we’re going to insert some sample performance counters into the config table. The counters you’re interested in can, and likely will, vary.

/* Insert some perfmon counters to be monitored */
Insert Into dbo.dba_perfCounterMonitorConfig
Select 'SQLServer:Buffer Manager', 'Page Life Expectancy', Null Union All
Select 'SQLServer:Locks', 'Lock Requests/sec', Null Union All
Select 'SQLServer:Locks', 'Lock Waits/sec', Null Union All
Select 'SQLServer:Locks', 'Lock Wait Time (ms)', Null Union All
Select 'SQLServer:Buffer Manager', 'Page reads/sec', Null Union All
Select 'SQLServer:Buffer Manager', 'Page writes/sec', Null Union All
Select 'SQLServer:Buffer Manager', 'Buffer cache hit ratio', Null Union All
Select 'SQLServer:Databases', 'Transactions/sec', 'AdventureWorks' Union All
Select 'SQLServer:General Statistics', 'Processes blocked', Null;

Now let’s create our proc. This proc will run for a specified time period and will *average* the counters over that time. I personally take snapshots every 15 seconds for 4 minutes; I have a scheduled task that runs this every 5 minutes. It’s not perfect, but it gives me a good idea of what’s happening on the server.

Create Procedure dbo.dba_perfCounterMonitor_sp
 
        /* Declare Parameters */
          @samplePeriod    int      =  240  /* how long to sample, in seconds */
        , @sampleRate      char(8)  =  '00:00:15'  /* how frequently to sample, in seconds */
        , @displayResults  bit      =  0  /* display the results when done */
As
/*********************************************************************************
    Name:       dba_perfCounterMonitor_sp
 
    Author:     Michelle Ufford, http://sqlfool.com
 
    Purpose:    Monitors performance counters.  Uses the dba_perfCounterMonitorConfig
                table to manage which perf counters to monitor.  
 
                @samplePeriod - specifies how long the process will try to monitor
                                performance counters; in seconds.
 
                @sampleRate - how long inbetween samples; in seconds.
 
                The average values over sample period is then logged to the
                dba_perfCounterMonitor table.
 
    Notes:      There are 3 basic types of performance counter calculations:
 
                Value/Base: these calculations require 2 counters. The value 
                            counter (cntr_type = 537003264) has to be divided 
                            by the base counter (cntr_type = 1073939712).
 
                Per Second: these counters are store cumulative values; the
                            value must be compared at 2 different times to
                            calculate the difference (cntr_type = 537003264).
 
                Point In Time:  these counters show what the value of the
                                counter is at the current point-in-time 
                                (cntr_type = 65792).  No calculation is 
                                necessary to derive the value.
 
    Called by:  DBA
 
    Date        User    Description
    ----------------------------------------------------------------------------
    2009-09-04  MFU     Initial Release
*********************************************************************************
    Exec dbo.dba_perfCounterMonitor_sp
          @samplePeriod     = 60
        , @sampleRate       = '00:00:01'
        , @displayResults   = 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;
 
Begin
 
    /* Declare Variables */
    Declare @startTime datetime
        , @endTime datetime
        , @iteration int;
 
    Select @startTime = GetDate()
        , @iteration = 1;
 
    Declare @samples Table
    (
          iteration     int             Not Null
        , objectName    nvarchar(128)   Not Null
        , counterName   nvarchar(128)   Not Null
        , instanceName  nvarchar(128)   Not Null
        , cntr_value    float           Not Null
        , base_value    float           Null
        , cntr_type     bigint          Not Null
    );
 
    Begin Try
 
        /* Start a new transaction */
        Begin Transaction;
 
        /* Grab all of our counters */
        Insert Into @samples
        Select @iteration
            , RTrim(dopc.object_name)
            , RTrim(dopc.counter_name)
            , RTrim(dopc.instance_name)
            , RTrim(dopc.cntr_value)
            , (Select cntr_value From sys.dm_os_performance_counters As dopc1
                Where dopc1.object_name = pcml.objectName
                And dopc1.counter_name = pcml.counterName + ' base'
                And dopc1.instance_name = IsNull(pcml.instanceName, dopc.instance_name))
            , dopc.cntr_type
        From sys.dm_os_performance_counters As dopc
        Join dbo.dba_perfCounterMonitorConfig As pcml
            On dopc.object_name = pcml.objectName
                And dopc.counter_name = pcml.counterName
                And dopc.instance_name = IsNull(pcml.instanceName, dopc.instance_name);
 
        /* During our sample period, grab our counter values and store the results */
        While GetDate() < DateAdd(second, @samplePeriod, @startTime)
        Begin
 
            Set @iteration = @iteration + 1;
 
            Insert Into @samples
            Select @iteration
                , RTrim(dopc.object_name)
                , RTrim(dopc.counter_name)
                , RTrim(dopc.instance_name)
                , dopc.cntr_value
                , (Select cntr_value From sys.dm_os_performance_counters As dopc1
                    Where dopc1.object_name = pcml.objectName
                    And dopc1.counter_name = pcml.counterName + ' base'
                    And dopc1.instance_name = IsNull(pcml.instanceName, dopc.instance_name))
                , dopc.cntr_type
            From sys.dm_os_performance_counters As dopc
            Join dbo.dba_perfCounterMonitorConfig As pcml
                On dopc.object_name = pcml.objectName
                    And dopc.counter_name = pcml.counterName
                    And dopc.instance_name = IsNull(pcml.instanceName, dopc.instance_name);
 
            /* Wait for a small delay */
            WaitFor Delay @sampleRate;
 
        End;
 
        /* Grab our end time for calculations */
        Set @endTime = GetDate();
 
        /* Store the average of our point-in-time counters */
        Insert Into dbo.dba_perfCounterMonitor 
        (
			  captureDate
			, objectName
			, counterName
			, instanceName
			, value
			, valueType
		) 
		Select @startTime
		    , objectName
		    , counterName
		    , instanceName
		    , Avg(cntr_value)
		    , 'value'
		From @samples
		Where cntr_type = 65792
		Group By objectName
		    , counterName
		    , instanceName;
 
        /* Store the average of the value vs the base for cntr_type = 537003264 */
        Insert Into dbo.dba_perfCounterMonitor 
        (
			  captureDate
			, objectName
			, counterName
			, instanceName
			, value
			, valueType
		) 
		Select @startTime
		    , objectName
		    , counterName
		    , instanceName
		    , Avg(cntr_value)/Avg(IsNull(base_value, 1))
		    , 'percent'
		From @samples
		Where cntr_type = 537003264
		Group By objectName
		    , counterName
		    , instanceName;
 
        /* Compare the first and last values for our cumulative, per-second counters */
        Insert Into dbo.dba_perfCounterMonitor 
        (
			  captureDate
			, objectName
			, counterName
			, instanceName
			, value
			, valueType
		) 
		Select @startTime
		    , objectName
		    , counterName
		    , instanceName
		    , (Max(cntr_value) - Min(cntr_value)) / DateDiff(second, @startTime, @endTime)
		    , 'value'
		From @samples
		Where cntr_type = 272696576
        Group By objectName
		    , counterName
		    , instanceName;
 
        /* Should we display the results of our most recent execution?  */
        If @displayResults = 1
            Select captureDate
                , objectName
                , counterName
                , instanceName
                , value
                , valueType
            From dbo.dba_perfCounterMonitor With (NoLock)
            Where captureDate = Cast(@startTime As smalldatetime)
            Order By objectName
                , counterName
                , instanceName;
 
        /* If you have an open transaction, commit it */
        If @@TranCount > 0
            Commit Transaction;
 
    End Try
    Begin Catch
 
        /* Whoops, there was an error... rollback! */
        If @@TranCount > 0
            Rollback Transaction;
 
        /* Return an error message and log it */
        Execute dbo.dba_logError_sp;
 
    End Catch;
 
    Set NoCount Off;
    Return 0;
End
Go

Like I said, it’s not perfect, but it gets the job done. :)

Getting an error about dba_logError_sp? Take a look at my error handling proc.