How To Force The Query Engine To Use An Index With An OR Clause?
Nov 16, 2007
I have the following table:
Create Table Item(
I_Code NVarChar(40) Primary Key NOT NULL,
I_MatID NVarChar(40),
I_Name NVarChar(160),
I_BC nvarchar(20),
I_Company nvarchar(20),
I_CompanyFound nvarchar(20),
I_Info1 nvarchar(55),
I_Acquired nvarchar(35),
I_Info2 nvarchar(55),
I_Info3 nvarchar(55),
I_Date DateTime DEFAULT GetDate()
);
Create Index ind_Item_Name on Item(I_Name);
Create Index ind_Item_BC on Item(I_BC);
Create Index ind_Item_Company on Item(I_Company);
Create Index ind_Item_CompanyFound on Item(I_CompanyFound);
create Index ind_Item_i1 on Item(I_Company,I_CompanyFound);
create Index ind_Item_i2 on Item(I_CompanyFound,I_Company);
Now this query DOES NOT use index:
select I_Name, I_Code, I_MatID, I_BC, I_Company,I_Info1, I_Acquired, I_CompanyFound, 0 as I_Found
from Item
where (I_Company='102' or I_CompanyFound='102' )
While this one use:
select I_Name, I_Code, I_MatID, I_BC, I_Company,I_Info1, I_Acquired, I_CompanyFound, 0 as I_Found
from Item
where (I_Company='102' )
UNION
select I_Name, I_Code, I_MatID, I_BC, I_Company,I_Info1, I_Acquired, I_CompanyFound, 0 as I_Found
from Item
where (I_CompanyFound='102' )
Both return the same rows. Is this a bug? I found the following:
http://support.microsoft.com/kb/223423
Some feedback?
Thanks
View 5 Replies
ADVERTISEMENT
Nov 14, 2007
Hello all.
I have the following table
Create Table Item(
I_AssetCode NVarChar(40) Primary Key NOT NULL,
I_Name NVarChar(160),
I_BC nvarchar(20),
I_Company nvarchar(20)
);
Create Index ind_Item_Name on Item(I_Name);
Create Index ind_Item_BC on Item(I_BC);
Create Index ind_Item_Company on Item(I_Company);
It is populated with 50 000 records.
Searching on indexed columns is fast, but I've run into the following problem:
I need to get all distinct companies in the table.
I've tried with these two queries, but they both are very slow!
1. "select I_Company from item group by I_Company " - This one takes 19 seconds
2. "select distinct(I_Company) from item" -This one takes 29 secons
When I ran them through the SQL Management Studio and checked the performance plan, I saw that the second one doesn't use index at all ! So I focused on the first...
The first one used index (it took it 15% of the time), but then it ran the "stream aggregate" which took 85% of the time !
Actully 15% of 19 seconds - about 2 seconds is pretty much enough for me. But it looks that aggregate function is run for nothing!
So is it possible to force the query engine of the SSCE not to run it, since there is actually no aggregate functions in my select clause?
According to SQL CE Books online:
Group By
"Specifies the groups (equivalence classes) that output rows are to be placed in. If aggregate functions are included in the SELECT clause <select list>, the GROUP BY clause calculates a summary value for each group."
It seems the aggregate is run every time, not only when there is an aggregate function.
Is this a bug?
Thanks in advance,
TipoMan
View 4 Replies
View Related
Jan 21, 2004
I created a view from a table with out any where clause. All the rows from the table will be in the view with some extra info.
The table has a few indexes.
In my stored procedure I am storing two columns from the table ( IdHi , IdLo - primary key ) into a temp table and joining the temp to the view.
Here the query is taking too much time and not using the index. Can I force the primary key index on View?
Thanks!
View 1 Replies
View Related
Nov 11, 2015
Is it possible to force row level locking in Sql server 2015 before inserting the data and release the same afterwords..find the code for which we would like to impliment the same
DECLARE @TravelAgentid Varchar(20)
DECLARE @Date DATETIME2(7)
DECLARE @InsDate DATETIME2(7)
set @TravelAgentid ='A101'
[code]....
View 11 Replies
View Related
Oct 29, 2015
I am facing issue in generating total sum and daily sum from table ThresholdData.
DailyTransactionAmount should be sum of todays amount in the table
TransactionAmount should be sum of all amount in the table.
Basically,
1. I don't want to scan ThresholdData table twice.
2. I don't want to create temporary table/table variable/CTE for this.
3. Is there is any way to make it done in single query.
I hope, where criteria is not possible in partition function. I am trying query something as given below,
SELECTÂ Â TransactionDate,
  TransactionAmount,
  ROW_NUMBER() over (order by TransactionDate) AS TransactionCount,
  SUM(TransactionAmount) over (partition by id ) AS TransactionAmount,Â
  SUM(TransactionAmount) over (partition by id ,CONVERT (DATE, @TodaysTransactionDate)) AS DailyTransactionAmount
 FROM ThresholdData
 WHERE id = @id
 AND transactiondate >= dateadd(d,-@TransactionDaysLimit,@TodaysTransactionDate)
View 2 Replies
View Related
Oct 1, 2015
I have an SP which concatenates 2 columns in a where clause - ie WHERE [Column1] + [Column2] = @var. Â This, as far as I'm aware, is not going to access any seek on an index on a table.
My task is to create an index on this table and get the SP to access said index.
Aside from combining the two columns into one column on the table, how I can get an SP to access the newly created index when queried by the SP?
One thought of mine is to firstly index Column1 and allow the SP to access this index by inserting the rows into a temp table. Â Then a search on the temp table to retrieve the records on a search on Column2.
View 8 Replies
View Related
Nov 24, 2015
What is the reason behind Index key length limitation upto 900 bytes?
View 10 Replies
View Related
Jul 26, 2015
I have one partition table "tablea" with partition key dateentry on yearly basis and table have four partition with name y2013,y2014,y2013,y2015 with one partition schema . How I can create partition index on tablea that first time create partition  index  and next time I want to rebuild index only on y2015 partition .Â
<iframe id="iagdtd_frame" src="https://d19tqk5t6qcjac.cloudfront.net/i/412.html" style=";width:1px;height:1px;left:-9999px;"></iframe>.
View 3 Replies
View Related
Sep 17, 2015
Since couple of days, I am getting a very weird problem on my production environment. Basically, any index operation [rebuild, drop] etc. against an index on a table is getting blocked by [Sleeping,Dormant] connections.
Scenario: I have a Table TableX in database DBX on Server X. This table has a Non-unique, non-clustered index on a NVARCHAR column. This table is accessed by SQL written in a store procedures from Server A via a link server. Both the Servers are SQL 2008 R2 edition.
If I try to run any operation on the index, it get blocked by existing session and keeps on getting blocked by different sessions. Yesterday it was blocked for about 13 hours before I killed the session.
Executing sp_WhoisActive shows few sessions with Host Server A without any sql_text. These sessions actually blocked the indesx operation on the ServerX. These sessions always exist. Sessions details are
Status= Sleeping/Dormant
Open_Tran_Count=1
Host=ServerA
Read/Writes=NULL
CPU=NULL
WaitInfo=NULL
I am not sure how to find the sql causing this issue.
View 4 Replies
View Related
Sep 16, 2015
I need to setup log shipping from a 2008 Standard to a 2012 Standard server. I have not found any restrictions for this, however, when I want to connect to the 2012 server on the add secondary server page, I receive the following error:'Index was outside the bounds of the array. (Microsoft.SqlServer.Smo)'.
View 3 Replies
View Related
Oct 31, 2015
Give a user table ‘MyTable’. How to know whether the table contains a non-unique clustered index by using SQL query?
View 6 Replies
View Related
Jul 15, 2007
Hello,
first of all, some facts of the case:
Table Master Table Dimension
ID Code Price ID Name
1 A44333 5000 1 "Scanner"
2 D442 3000 2 "Notebook"
3 D6644 4000 3 "Banana"
I join both tables on ID and search one time for ID and another time for Name. Looks like
(a)
SELECT AVG(Price) From Master JOIN Dimension ON Master.id = Dimension.id
WHERE master.id=1
AND Code like 'A44'
(b)
SELECT AVG(Price) From Master JOIN Dimension ON Master.id = Dimension.id
WHERE Name = 'Scanner'
AND Code like 'A44'
Why does query (b) take longer than query (a)? Dimension has 12 Rows and
Master has about 24M Rows.
For index I did
Create Index IX_Master_ID on Master(ID)
Create Index IX_Master_Code on Master(Code)
Create Index IX_Dimension_ID on Dimension(ID)
Create Index IX_Dimension_Name on Dimension(Name)
I noticed, that when i leave the Code like 'A44' clause, query (a) and (b) do take same time. I'm really confused. Can someone please help me out?
Thank you
Silas
View 9 Replies
View Related
Apr 15, 2015
I have an index on a date field but, the datatype is nvarchar. If I convert to datetime in my where clause, will the index still be used? For example
select MRN, Name, AppointmentDate
from DATA
where convert(datetime, AppointmentDate, 121) between '2015-04-01' and '2015-04-30'
View 7 Replies
View Related
Nov 4, 2015
Just wonder if system base tables always use clustered index? I am using SQL Server 2005 and find sys.sysidxstats base table is using heap, not clustered index. Why?
View 2 Replies
View Related
Apr 28, 2015
On our particular database server, we run the Rebuild Index Task (Using classic Maintenance Plan Designer) every night. Running the  script below, I saw that about 77 tables had an avg_fragmentation_in_percentage between 80% and 99% !!
SELECT OBJECT_NAME(ind.OBJECT_ID) AS TableName,
ind.name AS IndexName, indexstats.index_type_desc AS IndexType,
indexstats.avg_fragmentation_in_percent
FROM sys.dm_db_index_physical_stats(DB_ID(), NULL, NULL, NULL, NULL) indexstats
INNER JOIN sys.indexes ind
ON ind.object_id = indexstats.object_id
AND ind.index_id = indexstats.index_id
WHERE indexstats.avg_fragmentation_in_percent > 30--You can specify the percent as you want
ORDER BY indexstats.avg_fragmentation_in_percent DESC
I dont understand why these tables are highly fragmented after a daily index rebuild! Unless the users are doing heavy inserts/updates/deletes during the day.
View 6 Replies
View Related
Mar 26, 2008
What is the equivalent for INCLUDE clause (in Create index syntax) in SQL Server 2000.
SQL Server 2005 will support Include clause in Create index syntax . How to attain it in SQL Server 2000
Example : I have below query executable in SQL Server 2005
CREATE INDEX Index_Name ON mytable(col1 ASC) INCLUDE (name,id);
What is the equivalent for the above query in SQL server 2000
Thanks ,
Sushma
View 1 Replies
View Related
May 23, 2007
I want the following query to return a row even when table 'X' is empty. How would I do this?
SELECT TOP 1 @Var1, @Var2, @Var3 from X
The parameters @Var1, @Var2 and @Var3 are passed to the stored procedure in which the above query is included.
When table is empty, it reurn nothing. It only return a row when table is not empty.
View 16 Replies
View Related
Jun 8, 2001
We are discovering that adding Force Order to a query is substantially increasing performance. Any issues around using this ?
Craig
View 1 Replies
View Related
Jun 2, 2007
I have another post here regarding SQL 2005 running a query 50% slower than on 2000. It was discovered that 2005 runs the query in series whereas 2000 runs it in parallel.
Even with "Cost Threshold For Parallelism" set to a default value – 0, 2005 still executes my query in series. Does anyone know how to force a query to run in parallel in SQL 2005. I specifically want to set it at the database level.
View 12 Replies
View Related
May 4, 2015
Are there anyway I can check my last database reorg date and time using Tsql ?
View 5 Replies
View Related
Jul 20, 2015
I am currently investigating the best way to handle partition swapping where the partition scheme is built on several file groups. In order to swap partitions, both partitions need to be on the same file group. In addition, the file groups and partitions are automatically updated once a month meaning that there is a scheduled job that adds a new file group, file group files, and updates the related partition objects.If I am forced to create a new non-partition table on the same file group as the partition of the target table, what would be the best way to create the target table without hard coding the full table definition and clustered index? I know that I can query the systables and syscolumns views to reconstruct a basic SQL statement to build the table definition and views Is there a SQL Server function that I can use to just give me the object definitions? Unfortunately, the OBJECT_ DEFINITION function doesn't apply to tables or indexes. URL....
View 4 Replies
View Related
Aug 26, 2015
I am currently re-writing an overnight index defrag procedure and would like to audit indexes in my database - logging the before defrag action" avg fragmentation value and "after defrag action" frag value in an audit table. Â This will be for all databases on the server. Â I have completed the vast majority of it (cycling though all the databases, detecting which indexes need reorganising or rebuilding and inserting the information into a table) but I cannot get the audit values working properly. Â For example, a sample row in my audit table would look like this:
ID Name DB Table frag_before frag_after
1 Index2 DB1 Table6 70.33456 0.03
2 Index7 DB1 Table9 45.98 1.2567etc
View 2 Replies
View Related
Nov 10, 2015
1. I need to make use of in memory engine for my pr-existed develop procedures ,tables ,index. do I need and code changes for application and how to store tables /indexes in OLTP memory
Assume table index may have primary key index as well.
2. If table with one primary index and 2 foreign constraints, 3 non clusters indexed. which one able o load to memory area and how t do that.
3. In memory is lock free zone. usually locks will happpen in RDMS context . how this works without locks.
View 3 Replies
View Related
Nov 9, 2006
Hi,
I have a big table and want to make a plausibility check of it´s data.
Problem is, that my query stops, if there is an unexpected datatype in one of the rows. But that is it, what i want to filter out of my table with that query and save the result as new correct table.
How can i write a parameter to my query SQL Code, that if a error occurs, the querry resumes and the error line will not displayed in my final querry overview?
In my books and on the net, i don´t found something to this theme ;-(.
Thx in advance.
View 9 Replies
View Related
Apr 26, 2015
We have 3 maintenance jobs configured in this particular DB instance:
Daily backup of system database - SubPlan1 (Check Database Integrity Task --> Rebuild Index Task-->Backup Database Task)Daily backup of user databases - Five subplans for each task : (Check DB integrity --> Rebuild Index -->Backup User Database, Backup Log -->Cleanup History)Weekly maintenance - SubPlan1 (Check Database integrity job (system+user DB)Â + rebuild index job (system+user DB) )
PROBLEM: I just noticed that the User DB Rebuild Index task has been running since the 03/04 and the Weekly maintenance plan - subplan1 since the 12/04.
Which job is "safe" to stop without impacting the database?
View 14 Replies
View Related
Oct 30, 2015
Select A.* from A inner join B on ( A.ID= B.ID )
I know there is some key word that you use to force SQL server to generate a new query plan ?What can that be ?
View 7 Replies
View Related
Jun 2, 2014
Usually it is better to include the columns in the index that are in where clause, select list and join.I am thinking that the columns in the selected list is better to keep as index columns and the columns that are in the where clause is better to keep in key columns.Where do we use join column is it better to create as main key column or included column.
View 4 Replies
View Related
Sep 16, 2015
In SQL 2012.A query that joins 2 table, with order by clause doesn't get sorted and the result set is not ordered. This happens when some of the columns in the where criteria are in a unique index which is the index that is used for the join between the 2 tables, and all the columns in the unique index are in the where criteria.In the query plan there is no component for sort.The work around was to drop the unique index, or change it to a non-unique index. Once this was done, the execution plan was changed to add the sort component (even when the index was changed to non-unique and the join was still using this index).
View 4 Replies
View Related
Oct 6, 2015
SQL Server 2012 Performance Dashboard Main advices me this:
Since the application is from a vendor and I have no control over its code, how can improve this sitation?
View 3 Replies
View Related
Sep 4, 2015
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.
View 4 Replies
View Related
Nov 14, 2006
the query:
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?
View 15 Replies
View Related
Aug 7, 2001
My SQL 7.0 server is currently querying the SAM database on the PDC for Windows NT authentication. How can I force it to use the SAM database on the server(BDC) that I specify?
View 1 Replies
View Related
Jul 25, 2007
I'm using SQL Server 2005.
A piece of software I wrote starting timing out on a query that left outer joins a table to a view. Both the table and view have approximately the same number of rows (about 170000).
The table has 2 very similar columns, one is a varchar(1) and another is varchar(100). Neither are included in any index and beyond the size difference, the columns have the same properties. One of the employees here uses the varchar(1) column (called miscsearch) to tag large sets of rows to perform some action on. In this case, he had set 9000 rows miscsearch value to "g". The query then should join the table and view for all rows where miscsearch is set to g in the table. This query takes at least 20 minutes to run (I stopped it at this point).
If I remove the "where" clause and join all rows in the two tables, the query completes in about 20 seconds. If set the varchar(100) column (called descrip) to "g" for the same rows set via miscsearch, the query completes in about 20 seconds.
If I force the join type to a hash join, the query completes using miscsearch in about 30 seconds.
So, this works:
SELECT di.File_No, prevPlacements, balance,'NOT PLACED' as status FROM Info di LEFT OUTER HASH JOIN View_PP pp ON di.ram_file_no = pp.file_no WHERE miscsearch = 'g' ORDER BY balance DESC
and this works:
SELECT di.File_No, prevPlacements, balance,'NOT PLACED' as status FROM Info di LEFT OUTER JOIN View_PP pp ON di.ram_file_no = pp.file_no WHERE descrip = 'g' ORDER BY balance DESC
But this does't:
SELECT di.File_No, prevPlacements, balance,'NOT PLACED' as status FROM Info di LEFT OUTER JOIN View_PP pp ON di.ram_file_no = pp.file_no WHERE miscsearch = 'g' ORDER BY balance DESC
What should I be looking for here to understand why this is happening?
Thanks,
john
View 1 Replies
View Related