Truncate Table Partition command

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Truncate Table Partition command

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Chris Hamam

Posted Thursday, November 25, 2010 6:49 PM

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Group: General Forum Members
Last Login: Tuesday, April 23, 2013 3:29 PM
Points: 73, Visits: 520

Great script Vidya!! Thanks for posting this!

I found the earlier comments from Maurice and JFoster quite helpful as I encountered the same issues.

I also found that if the exisitng partition existed on a non-Primary filegroup and contained TEXTIMAGE data for varchar(max) or TEXT data types, then the the switching did not working becuase the new table sets TEXTIMAGE to the default filegroup, which was PRIMARY in my scenario.

So I made some changes to this excellent script to change the default filegroup before creating the mirror table then it worked perfectly.

In the next post I will submit the modified script including everyones changes thus far and I hope you don't mind us adding these suggestions now, since you are busy currently.

Cheers
Chris

--Chris Hamam

Life's a beach, then you DIE (Do It Eternally)

Post #1026599

Chris Hamam

Posted Thursday, November 25, 2010 6:50 PM

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Group: General Forum Members
Last Login: Tuesday, April 23, 2013 3:29 PM
Points: 73, Visits: 520

IF EXISTS (SELECT * FROM sys.objects WHERE object_id = OBJECT_ID(N'[dbo].[truncate_partition]') AND type in (N'P', N'PC'))
DROP PROCEDURE [dbo].[truncate_partition]
GO

/*
- Procedure Name: dbo.TRUNCATE_PARTITION
- Date of creation: 06-Jan-2010
- Author- Mr. Vidhaydhar Vijay Pandekar
- Email-
vidya_pande@yahoo.com

- Description: Truncates specified Partition from partitioned table.
- Application:
1. To truncate the partition automatically and to avoid sequence of manual steps required for truncating partitions
2. As a replacement to the ALTER TABLE TRUNCATE PARITION statement of oracle. This becomes useful when oracle code
requires replacement for this statement while migrating to SQL Server.

- Input Parameters:
1. @SchemaName - Partitioned Table Schema Name
2. @TabName - Partitioned Table Name
3. @PartitionNo - Partition number to be truncated

- Command for execution- exec TRUNCATE_PARTITION 'SchemaName','TableName',PartitionNumber
i.e. exe TRUNCATE_PARTITION 'dbo','Table1',3
- Successful Test results for-
1 No Clustered Primary key and No Clustered Index
2 Clustered Primary key
3 No Primary key and Clustered Index
4. Non Clustered Primary key
- Change History
v1.0 Creation - 06-Jan-2010
V2.0 Modied - 9th Feb-2010- Table Schema name issue resolved
V3.0 Modified- 10th Feb 2010 - step1.5 Added functionality to consider if source table/ partition is compressed????
v4.0 Modified-11th Feb 2010 - Step 2- modified Pk related issue
v4.1 16 Sep 2010 - Maurice Peek - Step 2 added index clause to join condition
v4.2 03 Nov 2010 - J foster - Step 2 added order by clause
v4.3 24 Nov 2010 - Chris Hamam - Step 3 moved to Step 0 to allow setting of default filegroup before creating new table schema
*/

CREATE PROCEDURE [dbo].[truncate_partition] @SchemaName VARCHAR(20),@TabName VARCHAR(100), @PartitionNo INT
AS
BEGIN

SET NOCOUNT ON

BEGIN TRY

/* Step0- v4.3 - Start identify file group of partition to be truncated*/

Declare @filegroup varchar(50)
SELECT @filegroup=
CASE
WHEN fg.name IS NULL THEN ds.name
ELSE fg.name
END
FROM sys.dm_db_partition_stats p
INNER JOIN sys.indexes i
ON i.OBJECT_ID = p.OBJECT_ID AND i.index_id = p.index_id
INNER JOIN sys.data_spaces ds
ON ds.data_space_id = i.data_space_id
LEFT OUTER JOIN sys.partition_schemes ps
ON ps.data_space_id = i.data_space_id
LEFT OUTER JOIN sys.destination_data_spaces dds
ON dds.partition_scheme_id = ps.data_space_id
AND dds.destination_id = p.partition_number
LEFT OUTER JOIN sys.filegroups fg
ON fg.data_space_id = dds.data_space_id
LEFT OUTER JOIN sys.partition_range_values prv_right
ON prv_right.function_id = ps.function_id
AND prv_right.boundary_id = p.partition_number
LEFT OUTER JOIN sys.partition_range_values prv_left
ON prv_left.function_id = ps.function_id
AND prv_left.boundary_id = p.partition_number - 1
WHERE
OBJECTPROPERTY(p.OBJECT_ID, 'ISMSSHipped') = 0
AND p.index_id IN (0,1)
AND OBJECT_NAME(p.OBJECT_ID)=@TabName
AND p.partition_number=@PartitionNo

/* end identify file group of partition to be truncated*/

--before creating the schema, change the default Filegroup to accommodate text LOBs
declare @sql varchar(8000)

IF NOT EXISTS (SELECT name FROM sys.filegroups WHERE is_default=1 AND name = @filegroup)
begin
set @sql = 'ALTER DATABASE backoffice MODIFY FILEGROUP ' + @filegroup + ' DEFAULT'
exec (@sql)
end
--end v4.3 changes

BEGIN TRANSACTION;

/* Step-1 start create staging table*/
DECLARE @PkIndex VARCHAR(200)
DECLARE @CreateTab VARCHAR(8000)
SELECT @CreateTab='select top 0 * into '+@SchemaName+'.'+@TabName+'_'+CONVERT(VARCHAR(5),@PartitionNo)+' from '+@SchemaName+'.'+@TabName
EXEC (@CreateTab)
/* End create staging table*/

--STEP 1.5
-- ADDED ON 10th Feb 2010. Added functionality to the script of source partitioned table/ partition is compressed.

declare @IsCompressed int
declare @CompressionType varchar(10)
declare @altStatement varchar(1000)
SELECT @IsCompressed=data_compression,@CompressionType=data_compression_desc
FROM sys.PARTITIONS where object_id=OBJECT_ID(@SchemaName+'.'+@TabName) and partition_number=@PartitionNo and index_id=0

If @IsCompressed=1
BEGIN
select @altStatement = 'ALTER TABLE '+@SCHEMANAME+'.'+@TabName+'_'+CONVERT(varchar(5),@PartitionNo)+' REBUILD PARTITION = ALL WITH (DATA_COMPRESSION = '+@CompressionType+')'
exec (@altStatement)
END

/*Step2-start add PK */
DECLARE @Pk_available INT =0
DECLARE @CI_available INT =0

SELECT @Pk_available =(SELECT 1 FROM sys.objects a inner join sys.indexes b ON a.object_id=b.object_id
WHERE a.object_id =OBJECT_ID(@SchemaName+'.'+@TabName) and (b.is_primary_key=1 AND b.index_id=1))
SELECT @CI_available =(SELECT 1 FROM sys.objects a inner join sys.indexes b ON a.object_id=b.object_id
WHERE a.object_id =OBJECT_ID(@SchemaName+'.'+@TabName) and (b.is_primary_key=0 AND b.index_id=1))
--added on 11th Feb 2010
if @Pk_available is null
set @Pk_available=0

if @CI_available is null
set @CI_available=0
------

IF (@Pk_available='1' or @CI_available='1')
BEGIN
DECLARE @TAB_ID1 int
SELECT @TAB_ID1= OBJECT_ID(@SchemaName+'.'+@TabName)
DECLARE @pkInfo table (SCHEMANAME VARCHAR(20),table_name varchar(100), pk_name varchar(100),columnName varchar(100), asckey char(1),IsUnique char(1))
INSERT INTO @pkInfo
(SCHEMANAME, table_name,pk_name,columnName,asckey,IsUnique)
SELECT
SCHEMANAME=@SchemaName,
B.NAME TABLE_NAME,
PK_NAME=
(SELECT a.name PK_NAME FROM sys.indexes a
WHERE A.OBJECT_ID=B.OBJECT_ID AND A.index_id=1),
COLUMN_NAME=
(SELECT name FROM sys.columns E WHERE E.OBJECT_ID=B.object_id AND E.column_id=D.column_id),
D.is_descending_key,
C.is_unique
FROM SYS.OBJECTS B
INNER JOIN sys.INDEXES C ON
B.object_id=C.object_id
INNER JOIN sys.index_columns D ON
B.object_id=D.object_id AND D.index_id=1 --v4.1
WHERE B.TYPE='U'
AND (C.index_id=1)
AND B.object_id=@TAB_ID1
ORDER BY D.key_ordinal --v4.2

DECLARE @alterstatement VARCHAR(8000)
DECLARE @Pkname VARCHAR(100),@columns VARCHAR(4000)

SELECT @Pkname=pk_name FROM @pkInfo

DECLARE @ALLcolumns TABLE (idcol1 INT IDENTITY,colname VARCHAR(100))
INSERT INTO @ALLcolumns (colname)SELECT columnName FROM @pkInfo
DECLARE @cnt INT
DECLARE @clncnt INT
SELECT @cnt=1
SELECT @clncnt=COUNT(*) FROM @ALLcolumns
DECLARE @cols VARCHAR(400)
SELECT @cols=''
while @clncnt>=@cnt
begin
select @cols=@cols+','+ colname FROM @ALLcolumns WHERE idcol1=@cnt
select @cnt=@cnt+1
end
select @columns=SUBSTRING(@cols,2,len(@cols))

end

if @Pk_available='1'
select @alterstatement='ALTER TABLE '+@SCHEMANAME+'.'+@TabName+'_'+CONVERT(varchar(5),@PartitionNo)+ ' ADD CONSTRAINT '+@Pkname+CONVERT(varchar(5),@PartitionNo)+' PRIMARY KEY CLUSTERED ('+@columns+')'
if @Pk_available<>'1'
SELECT @alterstatement='ALTER TABLE '+@SCHEMANAME+'.'+@TabName+'_'+CONVERT(varchar(5),@PartitionNo)+' ADD IDCOL INT CONSTRAINT PK_'+@TabName+'_'+CONVERT(varchar(5),@PartitionNo) +' PRIMARY KEY'
exec (@alterstatement)

/*end add PK */

/*Step4- Start Move table to File group of Partition Table */

if (@Pk_available='1' )
BEGIN
select @alterstatement ='ALTER TABLE '+@SCHEMANAME+'.'+@TabName+'_'+CONVERT(varchar(5),@PartitionNo)+ ' DROP CONSTRAINT '+@Pkname+CONVERT(varchar(5),@PartitionNo)+' WITH (MOVE TO ['+@filegroup+'])'
exec (@alterstatement)

select @alterstatement='ALTER TABLE '+@SCHEMANAME+'.'+@TabName+'_'+CONVERT(varchar(5),@PartitionNo)+ ' ADD CONSTRAINT '+@Pkname+CONVERT(varchar(5),@PartitionNo)+' PRIMARY KEY ( '+@columns+')'
exec (@alterstatement)
END

if (@Pk_available<>'1' )
BEGIN

select @alterstatement ='ALTER TABLE '+@SCHEMANAME+'.'+@TabName+'_'+CONVERT(varchar(5),@PartitionNo)+ ' DROP CONSTRAINT PK_'+@TabName+'_'+CONVERT(varchar(5),@PartitionNo) +' WITH (MOVE TO ['+@filegroup+'])'
exec (@alterstatement)

select @alterstatement='ALTER TABLE '+@SCHEMANAME+'.'+@TabName+'_'+CONVERT(varchar(5),@PartitionNo)+ ' drop column idcol'
exec (@alterstatement)
END

/*Step5- Create clustered index of staging table if it is there on source partitioned table to make the schema equal */
if (@CI_available='1' )
BEGIN
DECLARE @IsUnique char(1)
select @IsUnique= IsUnique from @pkInfo
IF @CI_available='1' AND @IsUnique='1'
select @alterstatement='CREATE UNIQUE CLUSTERED INDEX '+@Pkname+CONVERT(varchar(5),@PartitionNo)+' ON '+ @SCHEMANAME+'.'+@TabName+'_'+CONVERT(varchar(5),@PartitionNo)+ ' ( '+@columns+')'
IF @CI_available='1' AND @IsUnique='0'
select @alterstatement='CREATE CLUSTERED INDEX '+@Pkname+CONVERT(varchar(5),@PartitionNo)+' ON '+ @SCHEMANAME+'.'+@TabName+'_'+CONVERT(varchar(5),@PartitionNo)+ ' ( '+@columns+')'

exec (@alterstatement)

END

--Step6 - switch partition
select @alterstatement='alter table '+@SCHEMANAME+'.'+@TabName+' switch partition '+CONVERT(varchar(5),@PartitionNo)+' to '+@SCHEMANAME+'.'+@TabName+'_'+CONVERT(varchar(5),@PartitionNo)
exec (@alterstatement)

--Step7 drop staging table
select @alterstatement='drop table '+@SCHEMANAME+'.'+@TabName+'_'+CONVERT(varchar(5),@PartitionNo)
exec (@alterstatement)

END TRY
--Error Handling
BEGIN CATCH
Print 'Truncate Partition Failed due to error.'
SELECT
ERROR_NUMBER() AS ErrorNumber
,ERROR_SEVERITY() AS ErrorSeverity
,ERROR_STATE() AS ErrorState
,ERROR_PROCEDURE() AS ErrorProcedure
,ERROR_LINE() AS ErrorLine
,ERROR_MESSAGE() AS ErrorMessage;

IF @@TRANCOUNT > 0
ROLLBACK TRANSACTION;
END CATCH;

IF @@TRANCOUNT > 0
COMMIT TRANSACTION;

END

GO

--Chris Hamam

Life's a beach, then you DIE (Do It Eternally)

Post #1026600

c.p.rushworth

Posted Wednesday, August 29, 2012 2:49 AM

Forum Newbie

Group: General Forum Members
Last Login: Wednesday, May 22, 2013 11:03 AM
Points: 4, Visits: 7

I found another bug with an easy win:

Columns that include spaces need to be enclosed in square brackets.

DECLARE @ALLcolumns TABLE (idcol1 INT IDENTITY,colname VARCHAR(100))
INSERT INTO @ALLcolumns (colname)SELECT '[' + columnName + ']' FROM @pkInfo
DECLARE @cnt INT
DECLARE @clncnt INT
SELECT @cnt=1
SELECT @clncnt=COUNT(*) FROM @ALLcolumns
DECLARE @cols VARCHAR(400)
SELECT @cols=''
while @clncnt>=@cnt
begin
select @cols=@cols+','+ colname FROM @ALLcolumns WHERE idcol1=@cnt
select @cnt=@cnt+1
end
select @columns=SUBSTRING(@cols,2,len(@cols))

Excellent script that solved my problem exactly as required. It would be nice if Microsoft would include a TRUNCATE PARTITION function, but this does the job for now. Thanks.

Post #1351474

Dan Price-242213

Posted Monday, September 24, 2012 10:52 PM

Forum Newbie

Group: General Forum Members
Last Login: Wednesday, October 24, 2012 3:31 PM
Points: 3, Visits: 64

Two more issues with the script:
1. My SQL Server collation is case sensitive and therefore the procedure doesn't compile due to incorrect case usage
2. The code doesn't deal with computed columns - the created target table needs to recreate the computed column

If I get a chance I will revise the code and post.

Post #1363777

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