Select Col42 From Tbl With (NOT INDEX (myidx)) - Hint Saying Do Not Use Possible?
Nov 28, 2007
Hello!
I would like when I compare query plans to be able to compare
2 queries where the 1. is the "normal" version and the 2. the version where I forced compiler
not to use a specific index (i don't want to force at table scan, so hint index(0) can't be used).
The only way I see how I could achieve something similar is to to drop the index and compare response time
before and after. But building index could be time consuming...
Is it possible?
select col42 from tbl;
select col42 from tbl with...
Is possible to use like hint with subselect? , i mean i want to find all rows in table A that contains a word in a field(CALLED CONTENT) in table B, concretely in a field called content too, i show you the idea although the syntax is incorrect.
select ' + char (39) + @country + char (39) + ' as PAIS, A.ID, A.IDUSUARIO MSISDN, NULL AS MSISDN_COD, convert(char(19),A.FECHA_ALVENTO, 121) AS FECHA_MO_LOCAL, NULL AS FECHA_MO_LOCAL_D,
hello friends i have table1 and 200 coulumn of table1 :) i have 647.600 records. i entered my records to table1 with for step to code lines in one day :) i select category1 category2 and category3 with select code but i have just one index.. it is productnumber and it is primarykey..So my select code lines is so slow.. it is 7-9 second.. how can i select in 0.1 second ? Should i create index for category1 and category2 and category3 ? But i dont know create index.. My select code lines is below.. Could you learn me and show me index for it ?? or Could you learn me and show me fast Select code lines and index or etc ??? Also my search code line have a dangerous releated to attaching table1 with hackers :) cheersi send 3 value of treview1 node and childnode and child.childnode to below page.aspx :) Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load If Not Me.IsPostBack Then If Request("TextBox1") IsNot Nothing ThenTextBox1.Text = Request("TextBox1") End If If Request("TextBox2") IsNot Nothing ThenTextBox2.Text = Request("TextBox2") End If If Request("TextBox3") IsNot Nothing ThenTextBox3.Text = Request("TextBox3") End If End If Dim searchword As String If Request("TextBox3") = "" And Request("TextBox2") = "" Then searchword = "Select * from urunlistesi where kategori= '" & Request("TextBox1") & "'" End If If Request("TextBox3") = "" Then searchword = "Select * from urunlistesi where kategori= '" & Request("TextBox1") & "' and kategori1= '" & Request("TextBox2") & "'" End If If Request("TextBox3") <> "" And Request("TextBox2") <> "" And Request("TextBox1") <> "" Then searchword = "Select * from urunlistesi where kategori= '" & Request("TextBox1") & "' and kategori1= '" & Request("TextBox2") & "' and kategori2= '" & Request("TextBox3") & "'" End If SqlDataSource1.SelectCommand = searchword End Sub
One of the major syntax inside the SELECT statment is ..
WHERE FIELDA IN (SELECT PARAVALUE FROM PARATABLE WHERE SESSIONID = "XXXXX" AND PARATYPE='A') AND WHERE FIELDB IN (SELECT PARAVALUE FROM PARATABLE WHERE SESSIONID = "XXXXX" AND PARATYPE='B') AND WHERE FIELDC IN (SELECT PARAVALUE FROM PARATABLE WHERE SESSIONID = "XXXXX" AND PARATYPE='C') AND WHERE FIELDD IN (SELECT PARAVALUE FROM PARATABLE WHERE SESSIONID = "XXXXX" AND PARATYPE='D') AND WHERE FIELDE IN (SELECT PARAVALUE FROM PARATABLE WHERE SESSIONID = "XXXXX" AND PARATYPE='E') AND WHERE FIELDF IN (SELECT PARAVALUE FROM PARATABLE WHERE SESSIONID = "XXXXX" AND PARATYPE='F')
(It's to compare the field content with some user input parameter inside a parameter table... )
I think properly is that the SELECT ... IN is causing much slowness in the sql statement. I have indexed FIELDA , FIELDB, FILEDC etc and those PARAVALUE and PARATYPE in the PARATABLE table. But perfromance is still slow and execution takes >20 seconds for 200000 rows of records.
Do any one know if still any chance to improvide the performance like this?
Background:I am currently working on a mission critical web based applicationthat is accessed 24 hours a day by users from just about every timezone. We use MS SQL Server as our database and we have lots ofproblems with time-outs. We used to have lots of problems with locksuntil my management decided that we would use the WITH (NOLOCK) hinton EVERY select statement and WITH (ROWLOCK) on EVERY updatestatement. I have argued since the beginning that the NOLOCK hintshould be the exception and not the rule. Meanwhile we continue tohave problems related to time-outs.Problem:I'm the one that they call when there are time-out errors.I am a programmer first and a DBA when I have to be. I'd really liketo hear from some of you who are the opposite. I realize that thereare many factors that contribute to slow response from a databaseserver (indexes, RAM, disk speed, etc.), but what I really need tohear from an expert is whether or not using NOLOCK on **EVERY** queryin a 30GB database that has 344 tables is a bad idea.Thanks in advance,Stephen McMahonJoin Bytes!
Hi all If i have a view: CREATE VIEW vw_Users AS SELECT * FROM Users WITH(NOLOCK)
Is it suggested to use nolock in views? And if i needed to use this view in stored procs is it then suggested to apply the nolock hint? CREATE PROC [dbo] .[usp_GetCompanyUsers] AS SELECT * FROM Companies WITH(NOLOCK) JOIN vw_Users WITH(NOLOCK) --<< ---is this suggested?
Is possible to use like hint with subselect? , i mean i want to find all rows in table A that contains a word in a field(CALLED CONTENT) in table B, concretely in a field called content too, i show you the idea although the syntax is incorrect.
select ' + char (39) + @country + char (39) + ' as PAIS, A.ID, A.IDUSUARIO MSISDN, NULL AS MSISDN_COD, convert(char(19),A.FECHA_ALVENTO, 121) AS FECHA_MO_LOCAL, NULL AS FECHA_MO_LOCAL_D,
Hi All,I have a question about lock hint for you :If the first user currently run a select commandwith share lock and hold it. What kind oflock (lock hint) should be used by the second userin the select command (from the same table) so thatthis command will wait until the first user releasesthe lock ?I have tried using tablock, tablockx, xlock andupdlock hint in the select command for the seconduser, but it is not successful. Below is myunsuccessful test :The first user :Begin Transactionselect fprefix from ut1 where fprefix = '000'The second user :select * from ut1 with (tablockx)Please help meThanks in advanceAnita Hery*** Sent via Developersdex http://www.developersdex.com ***Don't just participate in USENET...get rewarded for it!
Can I use the NO Lock hint when running a SELECT against a view that points to another server? Will the no lock "travel" to the other server through the view?
Hi,I am making as SELECT query to fill a repeater, and I need to retrieve the index of each line of the query.ie, I want to get a dataset like :"0", "dataCol1", "dataCol2" for the first line"1", "dataCol1", "dataCol2" for the second line"2", "dataCol1", "dataCol2" for the third lineetc.Anyone knows if there is a sql statement that does it ?ThanksJohann
the following will work if I want to have UNIQUE Users.Name >> INSERT INTO [Users] (Name) SELECT Names FROM OtherUsers where OtherUsers.Names not in (select Name from Users)
but if I have an UNIQUE INDEX on Users CREATE UNIQUE INDEX [IX_Users] ON [Users] ([Name],[Category]) ON [PRIMARY] how can I do it ?
INSERT INTO [Users] (Name, Category) SELECT Names,Categories FROM OtherUsers where OtherUsers.Names + OtherUsers.Categories not in (select Name, Category from Users) ?
how can I insert it wih an index on 2 or 3 columns ?
I am new to SQL, especially use SQL in VC++ 6.0 framework.
I am told that creating INDEX on field(s) could speed up a query.
if I create a INDEX like the following <code> CREATE nonclustered INDEX IX_XYZ on TableA.field1 </code> Should I use the INDEX name IX_XYZ in some way in the following SELECT statement. Or the following SELECT statement will be carried out automatically based on the INDEX IX_XYZ.
<code> SELECT * FROM TableA WHERE field1 = xxx </code>
Eliko writes "i would like to add a coloumn to a select result, so there will be another coloumn with indexed running numbers for each record. how can i do it?
I need to get back the actual characters (without trailing blanks) contained in a char(43) field. So i tried: - substring(fieldname,1,len(fieldname)) which yields a 43 char column - using a variable that contains the actual length in substring(fieldname,1,@nchar)) the same. - tricking by concatenating the resulting string with a dummy like "" didn't work either. So apparently I am at a dead end. Anybody a clue, hint or solution???? Thanks to all contributors
Is it possible to place an exclusive row lock when running a SELECT query by using a lock hint (or otherwise).
Basically, when a select statement is run against a table I don't won't any other users to read that row until it has been updated - at some later stage.
Any suggestions on whether this is possible would be welcome.
I want to implement the following pattern (pseudo-code follows):
[for index in x different databases, where x is rather big]
create database MyDatabase_#{index}_Temp launch a dedicated ssis package on this database if I detect no error, proudly rename MyDatabase_#{index}_Temp to MyDatabase_#{index}_Last_Known_Good (drop the last_known_good first if it exist)
Later on, a consolidation process collect the data in Last_Known_Good versions of the databases.
My question: what is the simpliest way to achieve the rename operation (step 3) ?
I have tried an "alter database #{old_database_name} modify name = #{new_database_name}", but it works only once: once renamed, the database keeps the old mdf and ldf filenames, and the next create database will choke on this.
I have also tried to rename the logical filenames with ALTER DATABASE XXX MODIFY FILE (NAME = YYY, NEWNAME = ZZZ) but it doesn't work either.
I'd like to avoid specifying absolute mdf and ldf filenames myself, is it possible ?
An interesting discussion yesterday. One of the programmers asked about the use of the NOLOCK optimizer hint with an iterator table aka table of numbers. His comment was that this optimizer hint was not efficient. Rather than give a knee-jerk response I thought it would be better to ask. The main circumstance is that the iterator table is completely static with a fill factor of 100%. My purpose is to eliminate lock contention if I can.
Are there reasons to not use the NOLOCK hint in this case to potentially improve performance?
I want to Select a value from a Column which is named "Index" - and I don't want to change the name naturally. Is there a way to get a value without mentioning the Column name itself, rather the column number? "Incorrect syntax near 'Index'. If this is intended as a part of a table hint, A WITH keyword and parenthesis are now required. See SQL Server Books Online for proper syntax."
Occurs when I try to simply.. -> SELECT Index FROM Table WHERE Name like 'xyz' <-
My God! What happens if I miss a step, or put it in a different order??? I know I can specify ORDER BY StepID, but what about a missing step? I do have "missing ranges" script, but posting questions filtered through the script process may become a full-time job in itself...What to do, what to do...
Hi All,I want to lock 2 tables on 2 servers using TABLOCKXhint. These tables function as semaphores in myapplication. It means when the tables are lockedthen other users will not be able to access themand automatically they can not continue their works.I have tried using the following code, but itdoes not work. I always got the error :"Cannot specify an index or locking hint fora remote data source" on the select command.begin transelect * from server1.accounting.dbo.semtabwith (tablockx) where fprefix = '000'select * from server2.accounting.dbo.semtabwith (tablockx) where fprefix = '000'--commit tranThe error will disappear if I remove the servername, like this :select * from accounting.dbo.semtabwith (tablockx) where fprefix = '000'But, it does not meet my requirement.It only locks one table on one server(default).Please help meThanks in advanceJohn S.*** Sent via Devdex http://www.devdex.com ***Don't just participate in USENET...get rewarded for it!
I've got a dilemma which I hope someone has a solution to.
Let's say we're building a data mining model to predict aircraft reliability. In the training table we've got a column (among many others) with a unique aircraft ID, and then a column for the type (737,747) and then a column for the series (100,200,300). I.E. A 737-800 series would be "737" and "800".
There is in essence a parent-child relationship between these 2 columns. 737's should share a common set of reliability factors, and then those factors might be further defined by the series number (for instance, the 737 might have very reliable radar except for the 500 series). The series is analogous to what model year a car is. What I want to make sure doesn't happen is for the system to correlate a 747-400 and a 737-400 because they are the same series. They are totally independent if the model number is different.
My only idea was to merge the columns and have a single value "737-100". But it would seem then that the model won't have any idea that a "737-100" and "737-200" should have a lot more in common than a "737-100" because the values will be completely different.
I was hoping to find some sort of parent-child hint in the column properties but found none.
What solutions have other people tried? It sure seems that there should be an elegant solution for something like, but I'm missing it.
we have two SqlServer 2005 in cluster. The machines act very slow (although the CPU load is low) as soon as we achieve one of these operations: - drop / create database - restore database
We achieve those operations through the SqlServer Browser or via sqlcmd. Everything else is running smoothly.
Is there any known reason on why it can be so slow ?
best regards
Thibaut
(hope this is not too OT, but could not find any cluster-specific forum).
please explain the differences btween this logical & phisicall operations that we can see therir graphical icons in execution plan tab in Management Studio
I am setting up filtered replication(tran repl) for a table that is 2+ TB in size. The filtered rows are less than 1% of total size.When I run the snapshot, sometimes it complete in 27 mins(I have already optimized the snapshot agent profile) and sometimes it runs for ever. Mostly it runs forever, so the chances of it finishing soon are really very less.I have infact created filtered index just to cater to the query in the filter i.e. on the filter predicates. The reason its flipping flopping is due to the incorrect plan that it chooses. I can force the right index and the filtered query runs just fine but. I cannot use the query hints when I am adding the filter in replication as its not allowed.
I then went ahead and created the plan guides to force the best plan. But the plan guide was not used because even if there is a single space in the actual query that replication runs in the background the plan guide will not be used(testing on plan guides has proved this). The query needs to be ditto same including whitespaces and carriage returns. I then ran profiler and found that there is a view that replication creates and executes to extract the filtered rows and BCP it. Got the text of the view and created the plan guide on it but it was still not used because sp_helptext output seems to be different than what is actually being fired by replication internally.
Further, I collected the verbose log with level 2 and tried to find out if the main query shows up there with no success.
(a) I can't use the plan guide because I do not know the exact syntax(I mean I have the query but I do not know the white spaces, carriage returns, etc) and
(b) I cannot use query hint while filtering the article.
1. I cannot afford to have downtime. 2. I cannot use backup and restore option either.
I am stuck with that error when running my ASP.NET application on my production server for many weeks now and still don't have a complete solution to that problem.
I formerly posted that thread and read that other thread without success, so as I have made a few progress in delimiting the problem I am posting this new thread with the hope somebody will finally be able to help me.
To summarize:
1) I have developed an ASP.NET application, - on a Windows XP Pro SP2 computer - with VS studio 2005 Dev and included SQL 2005 engine - this application works fine on the dev computer
2) I have deployed the application on a production server which is: - a Windows 2000 SP 4 computer - with SQL Express SP1 with Advance services installed
When I launch the prod application I have this error: Login failed for user xxxxASPNET
I have found that I can bypass this error by doing the following: 1) manually attach my .mdf database with SQL Server Management Studio Express and specifying the field Attached as with myDatabaseName (in place of the default fullPhysicalPath/myDatabaseName.MDF) then detach it 2) change the auto generated connection string in web.config file from <add name="ConnectionString" connectionString="Data Source=.SQLEXPRESS;AttachDbFilename=|DataDirectory|myDatabaseName.mdf;Integrated Security=True;User Instance=True" providerName="System.Data.SqlClient"/> To <add name="ConnectionString" connectionString="Data Source=.SQLEXPRESS;AttachDbFilename=|DataDirectory|myDatabaseName.mdf;User ID=sa;Password=mySAPassword;database=myDatabaseName" providerName="System.Data.SqlClient"/>
That would have been an acceptable substitution solution but unfortunately my application also uses the new Login and Webparts features of VS 2005 which implies the automatic creation of an ASPNETDB.MDF database by VS. As I have no mean (or at least don't know how) of modifying the associated Connection String for that database (it does not appear in web.config) I cannot bypass the problem for it and thus the error still appears when the application try to use this database.
Please I really need help on this matter, I can provide any other useful information as needed (logs, sources ...)
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.
