SQL 7 created by default a clustered index on my primary key field. I would like to drop this index and recreate it on another field, but it is not allowing me. Error message states: "An explicit DROP INDEX is not allowed... It is being used for PRIMARY KEY CONSTRAINT enforcement." Can anybody advise how I can solve this? TIA
View 1 RepliesSo I'm reading http://www.sql-server-performance.com/tips/clustered_indexes_p2.aspx and I come across this:
When selecting a column to base your clustered index on, try to avoid columns that are frequently updated. Every time that a column used for a clustered index is modified, all of the non-clustered indexes must also be updated, creating additional overhead. [6.5, 7.0, 2000, 2005] Updated 3-5-2004
Does this mean if I have say a table called Item with a clustered index on a column in it called itemaddeddate, and several non-clustered indexes associated with that table, that if a record gets modified and it's itemaddeddate value changes, that ALL my indexes on that table will get rebuilt? Or is it referring to the table structure changing?
If so does this "pseudocode" example also cause this to occur:
sqlstring="select * from item where itemid=12345"
rs.open sqlstring, etc, etc, etc
rs.Fields("ItemName")="My New Item Name"
rs.Fields("ItemPrice")=1.00
rs.Update
Note I didn't explicitly change the value of rs.fields("ItemAddedDate")...does rs.Fields("ItemAddedDate")=rs.Fields("ItemAddedDate") occur implicitly, which would force the rebuild of all the non-clustered indexes?
I have a requirement to only rebuild the Clustered Indexes in the table ignoring the non clustered indexes as those are taken care of by the Clustered indexes.
In order to do that, I have taken the records based on the fragmentation %.
But unable to come up with a logic to only consider rebuilding the clustered indexes in the table.
create table #fragmentation
(
FragIndexId BigInt Identity(1,1),
--IDENTITY(int, 1, 1) AS FragIndexId,
DBNAME nvarchar(4000),
TableName nvarchar(4000),
[Code] ....
What is the easiest way to remember the definitions of clustered and non clustered indexes.
View 9 Replies View RelatedI'm changing the collation sequence of a field which is a primary, clustered key field via:
ALTER TABLE [dbo].[clusterAlgorithm] WITH NOCHECK ADD
PRIMARY KEY CLUSTERED
(
[ClusterAlgorithmClassName]
) ON [PRIMARY]
GO
Is there a way to drop the primary key designation before doing an alter table/alter column statement and then recreating the key, or must I drop and recreate the table?
Thanks,
Al
I would like to find information on Clustered and Non-clustered indexes and how B-trees are used. I know a clustered index is placed into a b-tree which makes sense for fast ordered searching. What data structure does a non-clustered index use and how? I tried to find info. on the web but couldn't get much detail...
View 3 Replies View RelatedHi all,
I have a huge table with million of rows, which has ONE Clustered index associated with the PRIMARY KEY, and there are some NON_Clustered indexes.
So,now i decided that, i dont need any more indexes ( not even one) on that table, but i need to maintain primary key on that table.
(a) So, how can i accomplish this (i.e.) having primay key but not having indexes on the table.
Thanks.
Looking for suggestions.
I have a database that is giving me a bad Index error. When I go to drop the necessary Index it is telling me that it either does not exist or cannot be dropped. However when I try to build that index, it tells me one already exists.
Is there any way to drop all of the indexes or at the very least see what the indexes are? This particular database is using 2005 Express.
Any help would be great!
Shawn
Hi
Has anyone heard of MS SQL Server 7 dropping indexes?
I had created an index on a table. The next day
the index had disappeared. Has anyone expirienced such
a problem?
Thanks in advance
Winston
I would like to know if there is a way to drop/ disenable all the indexes in a maintenance plan?
Or is it better to write scripts for dropping indexes and recreatig the same?
Purpose: Need to drop indexes(not the Primary key) before loading data and recreate the same after loading
Looking forward for suggestions/Solutions!
Thanks,
Janani
I am trying to drop a primary key on column LID and then create a clustered index on a new identity column ID and then add the primary key back on the LID. I am not able to do so due the table being in replication. here is the error:
Cannot alter the table '' because it is being published for replication.
How do I get past the error and create the Clustered Index on ID column in both publisher and subscriber?
I need to add syntax to a stored procedure to check for the existence of a specific indexes on a table before dropping it. If they do not exist I need it to NOT through an error message. Performing this on a table is relatively simple:
if exists (select * from sysobjects where id = object_id(N'[dbo].[TABLENAME]') and OBJECTPROPERTY(id, N'IsUserTable') = 1)
drop table [dbo].[TABLENAME]
Since indexes are not represented in sysobjects how can I do this?
Dear All,
i'm planning to drop all the non clustered indexes (as they are not congigured well) on production database, and run the latest script to create fresh non clustered indexes on specific columns.
now my doubts are
1)will the replication affect with dropping and recreating of indexes?
2)query to drop all the non clustered indexes on that database....
can i use the query delete from sysindexes where indid>1
will the query works for me to drop all the non clustered indexes?
3)is it necessary to generate a snapshot again after creating the new indexes? or can i drop and run at subscriber also?
please guide me in this regard
Arnav
Even you learn 1%, Learn it with 100% confidence.
This is for SQL 2005 and I know how to right click an index and do a "script index as create to new query window"
Basically, the one of the Microsoft scripts or views will tell us that we have 100+ indexes that exist for a database but that they are not being used by SQL server.
I will probably take them "offline" for a while and then drop them later on.
Before dropping them, I would like to be able to recreate them within minutes if system performance is degraded after this happens.
I was working on a script to pull this info out of the sys. tables like below but was wondering if anyone already has a script or an easier way to do this. (...and I don't want to right click 100 indexes within 137 tables and script to a new window and then compile a big script)
SELECT
'Create ' +
i.type_desc COLLATE SQL_Latin1_General_CP1_CI_AS +
' Index [' +
i.name +
'] ON ' +
t.name +
CHAR(10) +
c.name +
' ASC'
FROM sys.index_columns ic
Join sys.indexes i ON i.index_id = ic.index_id
JOIN sys.tables t ON ic.object_id = t.object_id
Join sys.columns c ON ic.column_id = c.column_id
WHERE
i.name = 'IX_Sellers_StatusID' and
c.object_id = t.object_id and
i.object_id = ic.object_id
Thanks,
Brian
Hi all,
I have a huge table 170 Gb of size. On that table we have 10 indexes
of around 12 GB in size.
The application is designed such that it bulk inserts the file in to
sql server. But , often we are getting time outs and some latching
isssues ( as can be seen in activity monitor).
So, will this be a good idea of dropping those indexes and then
recreating them again for better performance.
1) Its SQL 2005 Standard Edition SP1
2) Databases are in SIMPLE Recovery mode.
3) Database is not OLTP.
Thanks.
//N
hi,
how clustered indexes and non-clustered indexes been saved in memory?
non-clustered is a table of a references to the actual table?
and what about clustered indexes?
thanks.
Can anyone help ?
If you have a clustered index on an identity field are appends then forced onto the last page anyway because of the identity field order. So is there any advanbtage of having a clustered identity field ?
I need to convert several tables that currently have nonclustered indexes (primary keys) to clustered. Could anyone suggest what the easiest way of doing this would be.
View 1 Replies View Relatedhi
can someone tell me why there are only 249 non-clustered indexes,
is there any significance to that number
Hi,The more I read, the more confused I'm getting ! (no wonder they sayignorance is bliss)I just got back from the bookstore and was flipping through some SQL ServerAdministration books.One says, that to get the best query performance, youi do two things:1. Cover all the columns used in each SELECT (including the WHERE, ORDERBY , etc.) with an index2. Make sure it's a NON-CLUSTERED index.In this way, the author says, you avoid ever going directly to the basetables for data to resolve the query - i.e. it's resolved in the index.So, for example, he argues if you have:SELECT Lname,Fname, CompanyNamefrom Contactsinner join Customerson (contacts.custid = customers.custid)that you use two non-clustered indexes:1. Lname,Fname and custid from the Contacts table2. CompanyName and custid from Customers(as opposed to the standard approach of a clustered index on the PK's ofeach table)He says that clustered indexes don't speed up performance because they'rethe same as a full table scan. Should I drop clustered indexes from mylarge tables, given that there are multiple non-clustered indexes on them?Is it better to just use multiple non-clustered indexes on a heap table?Steve
View 1 Replies View RelatedWhat is the difference please?
View 1 Replies View RelatedIs any one know of a way of changing the clustered index without creating in the middle the default clustered index
we have a big table that we use to switch the clustered index
whenever we change the clustered index we cannot change it directly we have
to drop the existing than the default clustered is built
and than we can built the new one - since it is a big table the process
takes a lot of time and I wonder if we can do it directly from one cluster
index to another
What we do not is running the following SQL:
-- remove the old index
drop index Tbl.I_oldId
GO
-- now create the newId as clustered
CREATE CLUSTERED
INDEX [I_newId] ON Tbl ([newId])
ON [PRIMARY]
GO
Any Idea ?
Thanks
David
Using SQL Server 2000 ... hopefully not too dumb a question.
Is there a performance hit using Clustered Index on a table that gets a lot of deletes?
I'm creating a Transaction Log table that will get about 4,000 inserts per day. The value of some of this historical data is worthless after a while, so I delete it.
It occurs to me that this may create a lot of fragmentation. If so, is this cleaned up during weekly "Reorganize data and index pages" in the Maintenance Plan? Do I also need to select "Remove unused space from database files"?
Additional question: I though that care needed to be taken that a clustered key be a value that always increments (datestamp, identity key, etc), yet in this write-up, it shows using randomly generated key values. I'm confused. Wouldn't it have to reorganize everything with greater values to insert the new row into the appropriate spot?
http://www.sql-server-performance.com/gv_clustered_indexes.asp
Greetings all,
What's best practice for creating clustered indexes?! Should they be added to a table AFTER it has been populated or should the clustered index be created BEFORE?
Thanks for your advice in advance.
When you Upsize from Access using the wizard, unsurprisingly, a Unique index is created on the PK field, but these are all non-clustered. I presume there isn't one definitive answer to whether a index should be clustered or not, (which I understand means the table's records are held on disk contiguously), but generally, is it worth altering these all to become clustered?
Would you selectively cluster only those tables which you think would benefit most? Leave them all unclustered and look for bottle-necks?
1) is there a way in ss2005 to filter out nulls from a non clustered index?
2) if nulls are allowed in a non clustered non unique index, is there anything worth knowing about performance? I assume such an index would assist in a query that asks for rows where col A is or isnt null, but might it be better for us to reserve some invalid values for cols that would otherwise have been null and been in such an index? I'm worried specifically about a very large table we'll have, indexed on 2 columns that 50% of the time are both null. Partitioning isnt an option.
Does anyone have a recommendation for creating an index on a datetime column?
We use alot of dateranges in our statements and none of them perform very well.
Thanks
Pete Karhatsu
OK so I have this EAV system on a server that is old enough for kindergarten. Insanely enough, this company that makes more money than any of your gods can not buy me a new box.
Before you say "redesign", I need funding allocated for that. See my first statement.
Anywho, I have this page that touches the dreaded Value table and does a clustered index seek on it. Can't search faster than that, right? Well I am getting some funding for "performance tuning". I am wondering if maybe incorporating some clustered index views involving the value table and producing a smaller clustered index for it to seek may alleviate some of this. Any thoughts?
Hi,
I am studying for MCTS and through some of the course material it recommends that a low selectivity field i.e. First Name is a good canditate for a clustered index.
This goes against what is recommended online (completely the opposite) and goes against what I have been taught in the past.
What is correct for the exam?
Thanks
Currently we are facing some performance issue while accessing the archive data from the archive tables. the archive table is hugh and it contains around 100,000,000 records and this archive table is being used in few reports and in our commission cycles too. since we are facing performance issues we are rebuilding index once in a week on all the indexes on this archive table.
We have 1 clustered index and 5 non clustered indexes, every time when we rebuild all these indexes on this table it is taking more time, more often rebuilding the clustered index itself is taking approx. 1hr which is consuming more time. wanted to know is there any useful to rebuild clustered indexes or not, if yes then what would be the better way. if not then do we need to rebuild only non clustered indexes.
All of the 3 books I've read say it is not a good idea to create a clustered index on the primary key but it is created as the default. My question is has this changed in 2005? My understanding is to create the clustered index on columns used first in join clauses and then in where clauses, what is the answer?
View 14 Replies View RelatedI set up replication on our servers at work to streamline some procedures we run daily/weekly on them. This copies around 15 articles from two databases on the "Master" server to another server used for execution purposes. For the most part it was a pretty straight forward task and it seemed to work nicely; but I realised after some investigation that the non-clustered indexes weren't copying over to the child server.
I set the non-clustered indexes property in the properties of the publishing articles to "True" and generated a new snapshot, this seemed to work, but I've come into work this morning to find the property has reset to "False" and I have no indexes on the table again. Why is this happening and is there any way I can resolve the matter so the indexes are copied over concurrently?
Group,
I am getting the following error during replication of Database to a client:
The schema script 'Statutes_6.dri' could not be propagated to the subscriber. (Source: MSSQL_REPL, Error number: MSSQL_REPL-2147201001)
Get help: http://help/MSSQL_REPL-2147201001
Invalid locale ID was specified. Please verify that the locale ID is correct and corresponding language resource has been installed. (Source: MSSQLServer, Error number: 7696)
Get help: http://help/7696
Incorrect syntax near the keyword 'with'. If this statement is a common table expression or an xmlnamespaces clause, the previous statement must be terminated with a semicolon. (Source: MSSQLServer, Error number: 319)
The database is relatively small, only about 5 tables but there is a clustered Full-text Index.
Any ideas?
Thanks,
Frank