After reading some comments here I decided to look at tables to see if any had a clustered index that was a unique identifier. Yep. So if I have a table with a unique identifier as the primary key/clustered index and an identity column that is indexed, I would like to make the identity a clustered index (maybe even the primary key) and make the unique identifier a unique non-clustered index (not the primary key).
Does this sound reasonable?If I do this will I need to drop and recreate the other indexes? Or maybe just rebuild the other indexes?
Currently:
CREATE TABLE Payments (
IDX INT IDENTITY(1,1) NOT NULL,
GUID UNIQUEIDENTIFIER NOT NULL DEFAULT(NEWID()),
.....
-- many other columns
);
GO
ALTER TABLE [dbo].[PAYMENTS] ADD CONSTRAINT [PK_PAYMENTS_GID] PRIMARY KEY CLUSTERED ([GUID] ASC);
GO
CREATE NONCLUSTERED INDEX [IX_Payments_ID] ON [dbo].[PAYMENTS] ([IDX] ASC);
GO
Would like:
ALTER TABLE [dbo].[PAYMENTS] ADD CONSTRAINT [PK_PAYMENTS_IDX] PRIMARY KEY CLUSTERED (IDX ASC);
GO
CREATE UNIQUE NONCLUSTERED INDEX [IX_Payments_GUID] ON [dbo].[PAYMENTS] (GUID ASC);
GO
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?
SELECT a.AssetGuid, a.Name, a.LocationGuid FROM Asset a WHERE a.AssociationGuid IN ( SELECT ada.DataAssociationGuid FROM AssociationDataAssociation ada WHERE ada.AssociationGuid = '568B40AD-5133-4237-9F3C-F8EA9D472662')
takes 30-60 seconds to run on my machine, due to a clustered index scan on our an index on asset [about half a million rows]. For this particular association less than 50 rows are returned.
expanding the inner select into a list of guids the query runs instantly:
SELECT a.AssetGuid, a.Name, a.LocationGuid FROM Asset a WHERE a.AssociationGuid IN ( '0F9C1654-9FAC-45FC-9997-5EBDAD21A4B4', '52C616C0-C4C5-45F4-B691-7FA83462CA34', 'C95A6669-D6D1-460A-BC2F-C0F6756A234D')
It runs instantly because of doing a clustered index seek [on the same index as the previous query] instead of a scan. The index in question IX_Asset_AssociationGuid is a nonclustered index on Asset.AssociationGuid.
The tables involved:
Asset, represents an asset. Primary key is AssetGuid, there is an index/FK on Asset.AssociationGuid. The asset table has 28 columns or so... Association, kind of like a place, associations exist in a tree where one association can contain any number of child associations. Each association has a ParentAssociationGuid pointing to its parent. Only leaf associations contain assets. AssociationDataAssociation, a table consisting of two columns, AssociationGuid, DataAssociationGuid. This is a table used to quickly find leaf associations [DataAssociationGuid] beneath a particular association [AssociationGuid]. In the above case the inner select () returns 3 rows.
I'd include .sqlplan files or screenshots, but I don't see a way to attach them.
I understand I can specify to use the index manually [and this also runs instantly], but for such a simple query it is peculiar it is necesscary. This is the query with the index specified manually:
SELECT a.AssetGuid, a.Name, a.LocationGuid FROM Asset a WITH (INDEX (IX_Asset_AssociationGuid)) WHERE a.AssociationGuid IN ( SELECT ada.DataAssociationGuid FROM AssociationDataAssociation ada WHERE ada.AssociationGuid = '568B40AD-5133-4237-9F3C-F8EA9D472662')
To repeat/clarify my question, why might this not be doing a clustered index seek with the first query?
We are going to use SQL Sever change tracking. The problem is that some of our tables, which are to be tracked, have no primary keys. There are only unique clustered indexes. The question is what is the best way to turn on change tracking for these tables in our circumstances.
I desire to have a clustered index on a column other than the Primary Key. I have a few junction tables that I may want to alter, create table, or ...
I have practiced with an example table that is not really a junction table. It is just a table I decided to use for practice. When I execute the script, it seems to do everything I expect. For instance, there are not any constraints but there are indexes. The PK is the correct column.
CREATE TABLE [dbo].[tblNotificationMgr]( [NotificationMgrKey] [int] IDENTITY(1,1) NOT NULL, [ContactKey] [int] NOT NULL, [EventTypeEnum] [tinyint] NOT NULL,
I have created two tables. table one has the following fields,
Id -> unique clustered index. table two has the following fields, Tid -> unique clustered index Id -> foreign key of table one(id).
Now I have created primary key for the table one column 'id'. It's created as "nonclustered, unique, primary key located on PRIMARY". Primary key create clustered index default. since unique clustered index existed in table one, it has created "Nonclustered primary key".
My Question is, What is the difference between "clustered, unique, primary key" and "nonclustered, unique, primary key"? Is there any performance impact between these?
Hi there, I have a table that has an IDENTITY column and it is the PK of this table. By default SQL Server creates a unique clustered index on the PK, but this isn't what I wanted. I want to make a regular unique index on the column so I can make a clustered index on a different column.
If I try to uncheck the Clustered index option in EM I get a dialog that says "Cannot convert a clustered index to a nonclustered index using the DROP_EXISTING option.". If I simply try to delete the index I get the following "An explicit DROP INDEX is not allowed on index 'index name'. It is being used for PRIMARY KEY constraint enforcement.
So do I have to drop the PK constraint now? How does that affect all the tables that have FK relationships to this table?
We have a table, which has one clustered index and one non clustered index(primary key). I want to drop the existing clustered index and make the primary key as clustered. Is there any easy way to do that. Will Drop_Existing support on this matter?
I am unclear as to which Ip address to change the standard port on. When setting up a cluster you have multiple IP address's including the nic that is used for the heartbeat. I have not found any documention on how to change both nodes to listen on a port other than 1433..
I just ran the Database Engine Tuning Advisor on a relative complex query to find out if a new index might help, and in fact it found a combination that should give a performance gain of 94%. Fair enough to try that.
What I wonder about: The index I should create contains 4 columns, the last of them being the Primary Key column of the table, which is also my clustered index for the table. It is an identity integer btw.
I think I remember that ANY index does include the clustered one as lookup into the data, so having it listed to the list of columns will not help. It might at worst add another duplicate 4 bytes to each index entry.
Right? Wrong? Keep the column in the index, or remove it since it is included implicit anyway?
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.
I have a query which is primarily a victim of blocking and a blocker itself for other queries. I studied the plan for this and it shows a 42% cost on CI insert operation. The insert is happening on a table (Table A) that has a PK. This PK is not a running number. It is also a business key (primary key) in another master table (Table B).
My understanding is that the cost is heavy because -
1, this PK is not an incremental number. It could be any number not in a sequence. 2. while inserting into CI, there must be a scan happening to find out the location where the index will be inserted.
How can I reduce the cost?
1. Should I go for partitioning of this table Table A? I am trying to do this but I am not able to find any suitable partition key looking at the JOINS and filter clauses where this table is being used in the applicaiton. 2. Should I introduce a surrogate key (running number) as a primary key so that CI is faster ?
Web Base application or PDA devices use to initiate the order from all over the country. The issue is this table is not Partioned but good HP with 30 GB RAM is installed. this is main table that receive 18,0000 hits or more. All brokers and users are using this table to see the status of their order.
The always search by OrderID, or ClientID or order_SubNo, or enter any two like (Client_ID+Order_Sub_ID) or any combination.
Query takes to much time when ever server receive more querys. some orther indexes are also created on the same table like (OrderDate, OrdCreate Date and Status)
My Question are:-
Q1. IF Person "A" query to DB on Client_ID, then what Index will use ? (If any one do Query on any two combination like Client_ID+Order_ID, So what index will be uesd.? How does MS-SQL SERVER deal with these kind of issues.?
Q2. If i create 3 more indexes on ClientID, ORderID and OrdersubID. will this improve the performance of query.if person "A" search record on orderNo so what index will be used. (Mind it their would be 3 seprate indexes for Each PK columns) and composite-Clustered index is also available.?
Q3. I want to check what indexes has been used? on what search?
Q4. How can i check what table was populated when, or last date of update (DML)?
My Limitation is i Dont Create a Partioned table. I dont have permission to do it.
In Teradata we had more than 4 tb record of CRM data with no issue. i am not new baby in db line but not expert in sql server 2003.
I have a table<table1> with 804668 records primary on table1(col1,col2,col3,col4)
Have created non-clustered index on <table1>(col2,col3,col4),to solve a performance issue.(which is a join involving another table with 1.2 million records).Seems to be working great.
I want to know whether this will slow down,insert and update on the <table1>?
I have a view that joins a dozen tables with a million rows added per year by an application. I want to materialize it. The view is always filtered by date first on reports, then there are a few key transaction keys, but then many other fields required to make each row unique. I don't want to add these columns since they are large, many, not used for sorting or filtering, and may not define uniqueness in a future application design. I need a uniqueifier that is application agnostic. I prefer a bigint. So to store the materialized view ideally for reporting, I want to add the following clustered index to materialize the view:
CREATE unique CLUSTERED INDEX idx1 ON [dbo].[myview](myDate, key1, key2, key3, id bigint identity(1,1) NOT NULL)
And I get this error:
Msg 102, Level 15, State 1, Line 3 Incorrect syntax near 'bigint'.
Hi everyone, When we create a clustered index firstly, and then is it advantageous to create another index which is nonclustered ?? In my opinion, yes it is. Because, since we use clustered index first, our rows are sorted and so while using nonclustered index on this data file, finding adress of the record on this sorted data is really easier than finding adress of the record on unsorted data, is not it ??
I would like to put a Clustered Index on a date column in a current heap, but one question/concern.This heap every month has thousands of rows deleted and even more added later. How much of an issue will this cause the Clustered Index as far as page splits? I was thinking Fill Factor of 70%.I would normally just test and still will on Dev box, but my Dev box is much smaller than production as far as power.
I have created NONCLUSTERED index on table but my report is taking more time that's why i created columnstore NONCLUSTERED index on the same table but i have one query, if any table have row and column level index(same columns in index) . Which index query will consider.
i have created a fact table which has unique cluster index as below,
CREATE UNIQUE CLUSTERED INDEX [FactSales_SalesID] ON [dbo].[FactSales] (salesid ASC) WITH (DATA_COMPRESSION = PAGE) GO however later when i add CLUSTERED COLUMNSTORE INDEXES : CREATE CLUSTERED COLUMNSTORE INDEX CSI_FactSales ON dbo.FactSales WITH (DATA_COMPRESSION = COLUMNSTORE) GO
it prompts error.
Msg 35372, Level 16, State 3, Line 167 You cannot create more than one clustered index on table 'dbo.FactSales'. Consider creating a new clustered index using 'with (drop_existing = on)' option.
I have a clustered index that consists of 3 int columns in this order: DateKey, LocationKey, ItemKey (there are many other columns in this data warehouse table such as quantities, prices, etc.).
Now I want to add a non-clustered index on just one of the other columns, say LocationKey, like this: CREATE INDEX IX_test on TableName (LocationKey)
I understand that the clustered index keys will also be added as key columns to any NC indexes. So, in this case the NC index will also get the other two columns from the clustered index added as key columns. But, in what order will they be added?
Will the resulting index keys on this new NC index effectively be:
LocationKey, DateKey, ItemKey OR LocationKey, ItemKey, DateKey
Do the clustering keys get added to a NC index in the same order as they are defined in the clustered index?
Quick question about the primary purpose of Full Text Index vs. Clustered Index.
The Full Text Index has the purpose of being accessible outside of the database so users can query the tables and columns it needs while being linked to other databases and tables within the SQL Server instance. Is the Full Text Index similar to the global variable in programming where the scope lies outside of the tables and database itself?
I understand the clustered index is created for each table and most likely accessed within the user schema who have access to the database.
Is this correct?
I am kind of confused on why you would use full text index as opposed to clustered index.
We have SQL Server 008 R2 failover clustered instance.
Installation and everthing went smooth. But I'm getting a weired error
Unable to connect to SQL Server clustered instance from one of the nodes
When SQL Server Resources are on sql1:
Connect from SSMS from sql2--> NOT Able to connect to SQL instance (A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server) (Microsoft SQL Server, Error: 2))
Connect from SSMS from sql1-->Working fine
When SQL Server Resources are on sql2:
Connect from SSMS from sql1-->Working fine Connect from SSMS from sql2-->Working fine
I am trying to use an indexed view to allow for aggregations to be generated more quickly in my test data warehouse. The Fact Table I am creating the indexed view on is a partitioned clustered columnstore index.
I have created a view with the following code:
ALTER view dbo.FactView with schemabinding as select local_date_key, meter_key, unit_key, read_type_key, sum(isnull(read_value,0)) as [s_read_value], sum(isnull(cost,0)) as [s_cost] , sum(isnull(easy_target_value,0)) as [s_easy_target_value], sum(isnull(hard_target_value,0)) as [s_hard_target_value] , sum(isnull(read_value,0)) as [a_read_value], sum(isnull(temperature,0)) as [a_temp], sum(isnull(co2,0)) as [s_co2] , sum(isnull(easy_target_co2,0)) as [s_easy_target_co2] , sum(isnull(hard_target_co2,0)) as [s_hard_target_co2], sum(isnull(temp1,0)) as [a_temp1], sum(isnull(temp2,0)) as [a_temp2] , sum(isnull(volume,0)) as [s_volume], count_big(*) as [freq] from dbo.FactConsumptionPart group by local_date_key, read_type_key, meter_key, unit_key
I then created an index on the view as follows:
create unique clustered index IDX_FV on factview (local_date_key, read_type_key, meter_key, unit_key)
I then followed this up by running some large calculations that required use of the aggregation functionality on the main fact table, grouping by the clustered index columns and only returning averages and sums that are available in the view, but it still uses the underlying table to perform the aggregations, rather than the view I have created. Running an equivalent query on the view, then it takes 75% less time to query the indexed view directly, to using the fact table. I think the expected behaviour was that in SQL Server Enterprise or Developer edition (I am using developer edition), then the fact table should have used the indexed view. what I might be missing, for the query not to be using the indexed view?
We are using sql 2008r2 standard edition.One of our Production database is using default isolation Readcommitted.The transactions also using read committed. But we want change isolation level to read comitted snapshot isolation and test it to avoid deadlocks.
Is it possible to set in the transaction level for some queries or do we need to change entire database isolation level by using alter database "ALTER DATABASE AdventureWorks2008R2 SET READ_COMMITTED_SNAPSHOT ON"
Is 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
I have a merge replication. Currently works fine. Publisher & Distributor are on the same server. I need to change the location of the alternate folder for the snapshot files.
I’ll probably just change it through the GUI, but would I use sp_changedistpublisher or sp_changemergepublication if I were scripting everything?
My real concern is the subscribers. Do I have to ‘tell’ the subscribers where the alt folder has been changed to? Do I just run sp_changemergepullsubscription on the subscribers?