Transact SQL :: Index Fragmentation For Identity Column?
Jun 26, 2015
In my database all columns have Identity Value as a PK.
Now today I check Index Fragmentation I saw that many cluster and Non cluster Index are avg.Fragmentation is around 99 % I thought that in Identity column record is always inserted at bottom so there is no fill factor assigned to it.
So in this case Do I need to set Fill factor for Cluster and Non Cluster Index?
If Yes Then For PK How much - 95 % or what? and same for Non cluster or It should around 85 to 90
View 4 Replies
ADVERTISEMENT
Sep 18, 2015
I have a database in which I have some tables in which I have implemented Clustered columnstore Index. How to find the fragmentation levels of all these indexes via a single T-SQl script
View 3 Replies
View Related
Aug 12, 2009
when i alter non identity column to identity column using this Query alter table testid alter column test int identity(1,1) then i got this error message Msg 156, Level 15, State 1, Line 3 Incorrect syntax near the keyword 'identity'.
View 2 Replies
View Related
Feb 18, 1999
I have an non-clustered index defined on an identity column(statusid) on a table containing 200k rows. The query optimizer chooses to do a table scan when doing the following select. Why would this be.
SELECT * FROM STATUS
WHERE statusid = 10000
View 2 Replies
View Related
Mar 27, 2007
Hello,
I have a table with an Identity Column set up. I also have an index on the table that is set to Ignore Duplicate. Identity starts at 1 and is incremented by 1.
So first 5 rows inserted get identity
1
2
3
4
5
If I insert rows that get ignored because of the index with Ignore Duplicate, it is ignored correctly. But, the next row to get inserted will have an identity value of 7.
So, even though the insert was ignored because of the index with Ignore Duplicate, the Identity column was incremented behind the scenes.
Is there any way to avoid this?
Thanks,
John
View 3 Replies
View Related
Aug 2, 2015
I am extremely new to database design, and I ran into a problem that I know comes up often, however has many opinions...
Basically I have a table that is going to have 50+ columns. The natural key on this table is actually 8 columns wide, 4 of them being Varchar columns by default. (varchar(50)'s).
I have added an identity column, (1,1) to the table, however I put the clustered index on the 8 natural keys... My plan is to rebuild the clustered index once nightly when the system isn't in use (after 7 pm).
I know others would say it would be better to have the clustered key on the 1,1 column and then add indexes on the other 8 fields... However I don't quite understand why honestly...
Every single query against this table will use the 8 columns, and will NOT use the Identity column (1,1) because they are calls from other systems that do not know the Identity column....
Therefore if your database is set up for query speed, and every single query has to have a value for 8 columns to get a valid result, does it make sense to put a clustered index over the 8 columns?
If not why? Why is putting a clustered index on an identity column (that will literally never be used in a query) a better solution?
View 9 Replies
View Related
Nov 21, 2015
I am new in sql server. I am using TSQL2012 database. I have added a new column in processedOrderCount in Hr.Employees table. And created a trigger on Sales.Orders table that whenever orderId is updated it automatically updated processedOrderCount in Hr.Employees. There is a problem that the orderId is the identity column I can't update it. How can we work with identity column? the code of my trigger is:
If Object_id ('Sales.trig_Calculate_OrderProcessed', 'tr') is not null
Drop Trigger Sales.trig_Calculate_OrderProcessed
go
Create Trigger Sales.trig_Calculate_OrderProcessed
ON Sales.Orders
[Code] ....
View 2 Replies
View Related
Jun 22, 2008
What functions of tools do you use for managing index fragmentation?
DBCC?
I am working through MS Press SQL 2005 book and it mentions the
sys.dm_db_index_physical_stats function? It then give an example of code which is very involved.
Does anybody use this function?
Thanks
View 10 Replies
View Related
May 10, 2007
before rebuild index
---------------------
tablenameIndexname
avg_fragmentation_in_percent
Payoff_QuotePK_Payoff_QuoteDetail
83.3333333333333
ALTER INDEX ALL ON Payoff_Quote REBUILD
after issue the above statement result remain same.
View 1 Replies
View Related
Jun 24, 2007
Hi
When I run sys.dm_db_index_physical_stats on AdventureWorks.Production.Product, I get an average fragmentaion of 46%, 0%, 25% & 50% on the Indexes.
I run ALTER INDEX ALL ON AdventureWorks.Production.Product
REBUILD WITH (FILLFACTOR = 80, SORT_IN_TEMPDB = ON,
STATISTICS_NORECOMPUTE = ON)
and the index fragmentation does not change...
Why is that?? I have tried refreshing the table and the statistics but why does it look like rebuilding the indexes has done nothing?
View 1 Replies
View Related
Sep 25, 2007
I have a nice script that will look at the index fragmentation by using the DMV (sys.dm_db_index_physical_stats) and if its above a specificed threshhold, it will rebuild or reorg the index.
What I have noticed is that even after reorging and/or rebuilding the index, the fragmentation percent in the DMV does not change for some indexes. Other indexes are updated just fine.
Is this a result of updating statistics? Why would the fragmentation change for some indexes and not others? Why does it seem no matter how much rebuilding or reorging is done, the fragmentation percent for some indexes does not change?
- Eric
View 6 Replies
View Related
Jun 1, 2015
By mistake i deleted a record form prod table.
how can i enter that record back? i get this error.
INSERT INTO item_details(ItemID,Item_Name,price) VALUES(201, bag,10)
ItemID is  identity column. can i disable  identity column and enter and then enable using sql statement?
View 3 Replies
View Related
May 27, 2015
Is there anyway I can change Identity specification on column to yes ? and If I do that it supposed to take data as 1,2,3,4 like that?Â
But mine is not changing it's come up all data as 0. Is there any other way to do?Â
View 6 Replies
View Related
May 11, 2015
We have nightly job running to reorg all in one of our prod database. But the index on one of the table fragmenting quickly by the morning showing 90% fragmentation.
View 9 Replies
View Related
Feb 9, 2008
Hi,
It is natural that index gets fragment overtime. But I would like to know how you do the reindexing or defragment when your database table is big and you cannot afford the time to rebuild them. Thanks.
View 6 Replies
View Related
Nov 8, 2007
I have several databases in which our indexes have not been rebuilt/reorganized. I have worked primarily on SQL 2005 but with 2000 I am not familiar with Logical vs Extent fragmentation. And on the 2000 server there is high Logical Fragmentation (1000+%). With me rebuilding the indexes on the 2000 server databases, will this reduce performance or halt functionality of the servers while this process is running???
View 6 Replies
View Related
Sep 9, 2015
My current proc updates(updates using joins of two or three tables) millions of records as per the condition provided for each department.
However, when the proc fails it writes to a ErrorTable, ERROR_MESSAGE(), ERROR_SEVERITY() and which department has failed.
Since the records are updated keeping the selected departments in loop, I get the department in a temp variable.Now, I was asked to log the specific record where the failure was occured.Something like log the identity column value or primary key value which record has failed.
View 2 Replies
View Related
Apr 24, 2015
I am writing an Instead of Insert trigger. I would like to fire an error when inserting into an 'Identity' column. Since UPDATE([ColumnName]) always returns TRUE for insert statements, is there an easy/fast way around this? I don't want to use:Â
IF(EXISTS(SELECT [i].[AS_ID] FROM [inserted] [i] WHERE [i].[AS_ID] IS NULL))
here is my pseudo-code...
CREATE VIEW [org].[Assets]
WITH SCHEMABINDING
[Code] .....
-- How does this statement need to be written to throw the error?
--UPDATE([AS_ID]) always returns TRUE
IF(UPDATE([AS_ID]))
RAISERROR('INSERT into the anchor identity column ''AS_ID'' is not allowed.', 16, 1) WITH NOWAIT;
-- Is there a faster/better method than this?
IF(EXISTS(SELECT [i].[AS_ID] FROM [inserted] [i] WHERE [i].[AS_ID] IS NOT NULL))
RAISERROR('INSERT into the anchor identity column ''AS_ID'' is not allowed.', 16, 1) WITH NOWAIT;
-- Do Stuff
END;
-- Should error for inserting into [AS_ID] field (which is an identity field)
INSERT INTO [org].[Assets]([AS_ID], [Tag], [Name])
VALUES(1, 'f451', 'Paper burns'),
(2, 'k505.928', 'Paper burns in Chemistry');
-- No error should occur
INSERT INTO [org].[Assets]([Tag], [Name])
VALUES('f451', 'Paper burns'),
('k505.928', 'Paper burns in Chemistry');
View 7 Replies
View Related
Jun 2, 2014
We have few tables where we do truncate load or only do insert activities , why do the cluster index get fragmented very often to > 80%?
View 9 Replies
View Related
Nov 20, 2007
I need to manage the problem of negative performance implications when I fragment a 1TB+ DB. I want to perform Index Reorganization if fragmentation is no higher than 30%, and Index Rebuild if the fragmentation exceeds 30%.
Firstly can anyone recommend a script which uses sys.dm_db_index_physical_stats system to ascertain the
fragmentation level. Secondly, is there a technique I can employ to prevent the ONLINE operation completely killing performance on 27/4 production system?
ALTER INDEX REORGANIZE/REBUILD WITH (ONLINE=ON)
View 2 Replies
View Related
Apr 23, 2007
I have been testing methods to maintain indexes in a SQL Server 2005 database which has been migrated from SQL Server 2000. The compatibility level is still set to 80. I used the query below to inspect the degree of fragmentation amongst other things.
SELECT a.index_id
, name
, database_id
, avg_fragmentation_in_percent
,index_type_desc
,fragment_count
,page_count
FROM sys.dm_db_index_physical_stats (NULL, NULL, NULL, NULL, 'DETAILED') AS a
JOIN sys.indexes AS b ON a.object_id = b.object_id AND a.index_id = b.index_id
Some of the indexes in the database had a high degree of fragmentation based on the avg_fragmentation_in_percent value. I tried drop+create, rebuild and reorganise commands on those indexes. Predictably, drop + create was the most effective, but even that did not always reduce fragmentation much. Sometimes the fragmentation was the same no matter what method I used. Other times drop+create helped, rebuild made it worse.
What is going on?
View 11 Replies
View Related
Oct 22, 2014
I need to find out all the tables in database, which has FK columns and don’t have any Non-clustered index on them.
View 11 Replies
View Related
Nov 3, 2015
What are the disadvantages of columnstore index in Sql Server 2012
View 4 Replies
View Related
Jan 23, 2015
I have a table that has a clustered index that is only the identity column on the table. The table is somewhere around 200K rows and has 3800 pages in the index. We run our index maintenance every other day on this database using Ola's scripts and this index is rebuilt because it is 40-60% fragmented after 2 days. Overall, this isn't really too much of a problem since the index rebuild doesn't take too long, but I am puzzled as to how this index is getting fragmented since the only column in it is the identity.
CREATE TABLE [dbo].[Example](
[ExampleID] [int] IDENTITY(1,1) NOT NULL,
[ExampleCode] [varchar](10) NOT NULL,
[ForeignID] [int] NOT NULL,
[AnotherID] [int] NOT NULL,
[code]...
) ON [PRIMARY]There is nothing strange like updates to the identity happening and while some records are deleted, there has only been about 20,000 in the life of the table (months). Not enough to account for the level of fragmentation that we're seeing on the index.About the only thing I can think of that would cause fragmentation on this index in this scenario are:
1. Page splits caused by starting with a small value in one of the VARCHARs and later inserting a larger value
2. Page splits caused by the NULLABLE column, ExampleDate, starting with NULLs and later updating them to a date.
For #1, I had development check the update scenarios for the varchar columns, especially the varchar(1000) one, and they didn't see it as a common thing where the values would go from small (or empty) to large.
For #2, I checked and found that the only value for that column in the table is NULL so while it always starts as NULL, it never gets updated to anything else.
I've tried looking at sys.dm_db_index_operational_stats and the leaf_update_count is around 300,000, but unless those updates are causing page splits, I don't see how they would contribute to fragmentation.
View 9 Replies
View Related
Sep 17, 2007
I have a non-clustered index on a table. If I rebuild or reorganize it in SQL 2005, the total fragmentation percent reported by properties/fragmentation on the index stays at 33%.
Why doesn't the fragmentation go to 0% ?
If I totally drop/create the index, starts even higher, but beorg or rebuild simply goes to 33%. This even if using with use temp db for sort option.
View 1 Replies
View Related
Dec 11, 2007
I have been reworking my index maintenance jobs from my old SQL 2000 table and view references to the DMV's and System Tables in SQL 2005, and I noted that some of my indexes end up being more fragmented after a reorganization and or rebuild. That doesn't make much sense to me at all. The code I am executing is:
Code Block
print ' '
print '************* Beginning Index Updates for '+db_name()+' *************'
print ' '
DECLARE @tablename varchar(250),
@indexname varchar(250),
@fragpcnt decimal(18,1),
@indexid int,
@dbID int
-- Determine DB ID
SELECT @dbID = DB_ID()
DECLARE tnames_cursor CURSOR FOR
SELECT b.name, c.name, a.avg_fragmentation_in_percent, a.index_id
FROM sys.dm_db_index_physical_stats (@dbID, NULL, NULL, NULL, NULL) a
JOIN sys.indexes b ON a.object_id = b.object_id
AND a.index_id = b.index_id
JOIN Sys.objects c ON b.object_id = c.object_id
WHERE a.index_id > 0
ORDER by a.page_count DESC
OPEN tnames_cursor
FETCH NEXT FROM tnames_cursor INTO @indexname, @tablename, @fragpcnt, @indexid
WHILE (@@fetch_status = 0)
BEGIN
-- Declare and determine the tablename ID
declare @tablenameID int
select @tablenameID = object_id(@tablename)
IF @fragpcnt > 30
BEGIN
EXEC('ALTER INDEX ['+@indexname+'] ON ['+@tablename+'] REBUILD')
PRINT '***************************************************'
PRINT 'Index '+@indexname+' was rebuilt.'
PRINT 'Original framentation Percent: ' + convert(varchar, @fragpcnt) + '%'
SELECT @fragpcnt = avg_fragmentation_in_percent
FROM sys.dm_db_index_physical_stats (@dbID, @tablenameID, @indexid, NULL, NULL) a
JOIN sys.indexes b ON a.object_id = b.object_id
AND a.index_id = b.index_id
JOIN Sys.objects c ON b.object_id = c.object_id
PRINT 'Post Rebuild fragmentation Percent: ' + convert(varchar, @fragpcnt) + '%'
PRINT ''
END
ELSE IF @fragpcnt BETWEEN 5 AND 30
BEGIN
EXEC('ALTER INDEX ['+@indexname+'] ON ['+@tablename+'] REORGANIZE')
PRINT '***************************************************'
PRINT 'Index '+@indexname+' was Reorganized.'
PRINT 'Original framentation Percent: ' + convert(varchar, @fragpcnt) + '%'
SELECT @fragpcnt = avg_fragmentation_in_percent
FROM sys.dm_db_index_physical_stats (@dbID, @tablenameID, @indexid, NULL, NULL) a
JOIN sys.indexes b ON a.object_id = b.object_id
AND a.index_id = b.index_id
JOIN Sys.objects c ON b.object_id = c.object_id
PRINT 'Post Reorganization fragmentation Percent: ' + convert(varchar, @fragpcnt) + '%'
PRINT ''
END
ELSE
BEGIN
PRINT '***************************************************'
PRINT 'Index '+@indexname+' was left alone.'
PRINT 'Original framentation Percent: ' + convert(varchar, @fragpcnt) + '%'
PRINT ''
END
FETCH NEXT FROM tnames_cursor INTO @indexname, @tablename, @fragpcnt, @indexid
END
print ' '
print '************* NO MORE TABLES TO INDEX *************'
PRINT 'All indexes for the '+db_name()+' database have been updated.'
print ' '
DEALLOCATE tnames_cursor
Below are some snipits of the output:
***************************************************
Index _dta_index_wuci_history_8_1123587141__K2_K5 was rebuilt.
Original framentation Percent: 58.3%
Post Rebuild fragmentation Percent: 58.3%
***************************************************
Index PK__batchjob__776C5C84 was left alone.
Original framentation Percent: 0.0%
***************************************************
Index PK__ContactWebDetail__116A8EFB was rebuilt.
Original framentation Percent: 44.4%
Post Rebuild fragmentation Percent: 77.8%
***************************************************
Index PK__managed_object_s__5DCAEF64 was left alone.
Original framentation Percent: 0.0%
***************************************************
Index kb_IX_kb_scope_scope_role was rebuilt.
Original framentation Percent: 75.0%
Post Rebuild fragmentation Percent: 87.5%
***************************************************
Index PK__query__09A971A2 was left alone.
Original framentation Percent: 0.0%
***************************************************
Index PK__email_message__38996AB5 was rebuilt.
Original framentation Percent: 85.7%
Post Rebuild fragmentation Percent: 0.0%
***************************************************
If the index begins with PK, then it is the primary key index which is generally the clustered index on the table, but not always. If it has an IX on it, it is generally a non-clustered index on the table, but again not always. In the case of the above, the PK is a clustered index, and the IX is a non-clustered index.
Anyone have any ideas why this is functioning in this manner?
Thanks,
Jon
View 6 Replies
View Related
Sep 4, 2007
I am using sys.dm_db_index_physical_stats to identify indexes that need to be rebuilt based on a fragmentation limit. Once identified, I execute and ALTER INDEX... REBUILD on the index. If the index is clustered, only that index gets rebuilt for the table. After all the indexes are complete, I receive a report on the indexes that were rebuilt in the databases and what level of fragmentation the index was at before rebuilt. After checking these indexes, I still see that all the Primary Key indexes are still at the same fragmentation level. I run the process again and it does not change. I updated table usage and also ran update statistics after running the rebuild again, but the fragmentation does not change. Why can€™t these PK Clustered indexes be rebuilt as expected? Do I need to drop and recreate the PK before this fragmentation changes?
View 7 Replies
View Related
Dec 17, 2014
I've noticed that indexes in my AX 2012 database get very fragmented very quickly. Is this normal and that I should just defragment them regularly or is there a possible issue here that needs investigated?
View 6 Replies
View Related
Mar 10, 2007
I thought I would delve into index fragmentation and I found somegreat sql from many posters (thanks Erland!).My question is how bad is bad? I know this is very subjective.Some scripts I found would reindex if the LogicalFragmenation is over30%.I have some tables that are 98% (I'm guessing really bad). I know itall depends..more as a learning point: I found a table that had over 30%logicalfragmentation, I dropped the indexes, created then ran thescript that used type code segment:'DBCC SHOWCONTIG(' + @TableName + ') WITH TABLERESULTS, ALL_INDEXES,NO_INFOMSGS')In one case, the indexes for the table dropped below 30%, in anothercase the index was still fragmented ever after I dropped and re-created index.SQL Server 2005 x64 SP2This is the script I am running (I found this in another thread thatErland posted):SET NOCOUNT ONUSE ds_v6_sourceDECLARE @TableName VARCHAR(100)-- Create a table to hold the results of DBCC SHOWCONTIGIF OBJECT_ID('Tempdb.dbo.#Contig') IS NOT NULLDROP TABLE #ContigCREATE TABLE #Contig ([ObjectName] VARCHAR(100), [ObjectId] INT,[IndexName]VARCHAR(200),[IndexId] INT, [Level] INT, [Pages] INT , [Rows] INT ,[MinimumRecordSize] INT,[MaximumRecordSize] INT , [AverageRecordSize] INT,[ForwardedRecords] INT ,[Extents] INT, [ExtentSwitches] INT, [AverageFreeBytes]NUMERIC(6,2),[AveragePageDensity] NUMERIC(6,2), [ScanDensity]NUMERIC(6,2) ,[BestCount] INT ,[ActualCount] INT , [LogicalFragmentation] NUMERIC(6,2) ,[ExtentFragmentation] NUMERIC(6,2) )DECLARE curTables CURSOR STATIC LOCALFORSELECT Table_NameFROM Information_Schema.TablesWHERE Table_Type = 'BASE TABLE'OPEN curTablesFETCH NEXT FROM curTables INTO @TableNameSET @TableName = RTRIM(@TableName)WHILE @@FETCH_STATUS = 0BEGININSERT INTO #Contig EXEC('DBCC SHOWCONTIG(' + @TableName + ') WITHTABLERESULTS, ALL_INDEXES, NO_INFOMSGS')FETCH NEXT FROM curTables INTO @TableNameENDCLOSE curTablesDEALLOCATE curTables
View 8 Replies
View Related
Jul 20, 2005
hello everyone,we dropped the clustered & nonclustered indeces on a table, thenrebuilt them. logical fragmentation is near zero, but extentfragmentation is about 40%. how can this be if the indeces are brandnew?
View 2 Replies
View Related
Sep 17, 2015
How can we get the list of clustered columnstore index in a database in sql server 2014
View 3 Replies
View Related
Apr 26, 2015
We have a database with a table that contains around 180m records. Each day a further 70k are inserted. No records are ever deleted as this table is used for archiving only.Users are required to perform SELECTs on this table constantly but due to the high number of INSERTs the indexes become very fragmented very quickly. My aim is to avoid daily rebuilds of the indexes which is what our software house is telling us we have to do.
This is the DDL for the table:
CREATE TABLE [dbo].[Inventory](
[EAN] [bigint] NOT NULL,
[Day] [smalldatetime] NOT NULL,
[State] [int] NOT NULL,
[Quantity] [int] NULL,
[StockValue] [float] NULL,
CONSTRAINT [PK_Inventory] PRIMARY KEY CLUSTERED
[code]...
There are also three clustered Indexes on this table each referencing a single column. The problem from my side is that I cannot understand why the three columns in a primary key would also be configured as non-clustered indexes.My solution would be one of the following:
1. Accept the tables are going to be fragmented and require a daily rebuild (don't like this one!)
2. Partition the table
3. Remove the non-clustered Indexes and let the clustered index for the primary key do the work.
View 9 Replies
View Related
Jun 19, 2008
Hi,
I am having problem in bulk update of a sql server table haning identity column from a datatable( has no identity column) using sqlbulkcopy. I tried several approaches, but it does not show any error nor is the table getting updated. But the identity value seems to getting increased every time.
thanks.
varun
View 6 Replies
View Related
