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RE: Truncate Table Partition command

Chris Hamam — Thu, 25 Nov 2010 18:50:00 GMT

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 ASBEGIN SET NOCOUNT ONBEGIN 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 LOBsdeclare @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 changesBEGIN 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 > 0ROLLBACK TRANSACTION; END CATCH; IF @@TRANCOUNT > 0COMMIT TRANSACTION;ENDGO

RE: Truncate Table Partition command

Chris Hamam — Thu, 25 Nov 2010 18:49:04 GMT

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.CheersChris

RE: Truncate Table Partition command

vidya_pande — Fri, 05 Nov 2010 20:13:12 GMT

Thanks for your testing and feedback. Now a days im busy and not able to accomodate the feedback. Sorry for that.

RE: Truncate Table Partition command

jfoster-540652 — Wed, 03 Nov 2010 11:06:33 GMT

Very clever script, Vidya! Nice work.The only problem I encountered during testing was that the target table clustered indexes would sometimes get created with their columns in the wrong order. This would cause the SWITCH command to fail and return the error:Msg 4947, Level 16, State 1, Line 1ALTER TABLE SWITCH statement failed. There is no identical index in source table '<db_name>.<schema>.<src_tbl_name>' for the index '<idx_name>' in target table '<db_name>.<schema>.<trgt_tbl_name>' .The solution to this problem was a simple addition of ORDER BY ordinal position on the index columns at the end of this section: 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 WHERE B.TYPE='U' AND (C.index_id=1) AND B.object_id=@TAB_ID1[b] ORDER BY D.key_ordinal[/b]

RE: Truncate Table Partition command

Paul.Gamblen-594531 — Thu, 28 Oct 2010 04:20:12 GMT

Vijay,This is a gem. Nice work. I dont usually feel compelled to comment on forums but this saved me a lot of work and gave me an elegant solution, so well done.A couple of comments.I found that when dealing with a partition that had been row compressed the script did not create a row compressed empty table. This was because my partitions did not have an index = 1. Removal of this clause and everything ran smoothly.Secondly, the name of this article is slightly misleading (apologies for the literalness). The script does not truncate a partition, it removes it, as the switched out partition is never switched back in. To truncate a partition, you need to switch out, truncate then switch back in.For me the most beneficial aspects of this script is the ability to create an empty replica of an existing table through T-SQL. Well done.Paul.

RE: Truncate Table Partition command

maurice_peek — Tue, 29 Jun 2010 06:05:25 GMT

I found a little bug in the code. I tested some of the code for clustered indexes together with other indexes and it failed because when looking for the columns ofthe clustered indexes it also added those for the non-clustered indexes. The red part I added to solve this problem.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 [color="red"]AND D.index_id=1[/color] WHERE B.TYPE='U' AND (C.index_id=1) AND B.object_id=@TAB_ID1

RE: Truncate Table Partition command

vidya_pande — Wed, 17 Mar 2010 09:05:38 GMT

Yes second option is correct. it will keep on incrementing from the last IDENTITY value.

RE: Truncate Table Partition command

joewazen — Wed, 17 Mar 2010 03:41:10 GMT

Hello,if i have a table containing an auto increment unique id, this table is partitioned based on date time field.what happens to the auto increment values when i truncate a partition?Will the partitions that are still available inherit the truncated id's or will the id continue incrementing as if nothing happened?

RE: Truncate Table Partition command

vidya_pande — Sat, 20 Feb 2010 10:29:39 GMT

One more thing is this procedure takes care if the partition is compressed. One more manual step is eliminated. If you are doing it manually you need to find out compression type of Partition and Mirror/Dummy table should have same Compression.Regards,Vidhaydhar

RE: Truncate Table Partition command

vidya_pande — Sat, 20 Feb 2010 10:27:31 GMT

Hi Vinay,Yes, For truncating partition you need to create the mirror/dummy table with similar schema and on same file group where the partition is residing; and then use the Alter tables switch statement.Dont you think that considerable manual work is involved here? This procedure automates the all the steps involved. You dont need to know about schema of the table, file group of the partition etc, you do not need to create and drop the dummy tables etc.Also if you are migrating some code/database from Oracle to SQL Server where ALTER TABLE ..TRUNCATE PARTITION command is used, you can replace such statement by adding call to this procedure here.Regards,Vidhyadhar

RE: Truncate Table Partition command

bhushanvinay — Thu, 18 Feb 2010 13:03:58 GMT

I dont know if i am wrong but is there a easy way out for this.May be if i say.Partition function fx(10,20,30)partition scheme sc on fx all to primaryCreate Table blabla_bla ( i int primary Key scheme fx(i))on fx(i)create table blabla_bla_mirror( i int primary Key scheme fx(i))on fx(i))switch partiton x to blabla_bla_mirror (x)your partition is empty now drop table mirror.

Truncate Table Partition command

vidya_pande — Thu, 04 Feb 2010 17:41:38 GMT

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