Hi!
when WITH (NOLOCK) statement is used in a select statement, it allows to retrieved data from a set of data locked by another transaction. Is it possible to enforce this at connection level?
I mean to open a connection using sqlclient and enforce NOLOCK so that all select statements post to database using that connection are not locked by other transactions.
thanks in advance
Hello all.
I'm a litle confused about what's best to use, either isolation levels or locking per table.
Cause there are some queries in the stored procedures where I don't need locking i.e. when I check the status of client, but other queries where I do need locking like when I check the existence of a product.
What's best to use, can I combine both? Could you explain it thecnically?
lots of thanks in advance
client: ado.net 2.0 SqlClient, xp sp 2
server: sql server 2005, win 2k
I have a stored proc eg spProcA which does not start a transaction
If I call this proc from ado.net code without any transaction around it affecting the isolation level, the isolation level within the proc call is read committed, as expected
If I then call the same proc within a System.Transacstion.TransactionScope with a different isolation level eg Serializable, then i get the expected isolation level in the proc.
However, if i retry the proc without any transaction around it, the isolation level is now the same as the TransactionScope, (eg Serializable), and this persists until either the connection pool clears down (either because it becomes dormant or via an explicit ClearAllPools.
I can resolve this problem by setting the isolation level in every proc (or call to every proc), but i wondered if i am missing something more straight forward?
The problem that I am having is that with Visual Web Developer I am creating a webpage and having it directly put online, so for example when I start a new ASP.NET page, I select the location to be HTTP, with the location http://MYWEBSERVER/Website and for the language and Visual BasicI notice a couple of things, first that there is no longer a a link under the Main toolbar "Website" selection called the ASP.NET configuration. So how can I configure what I want to have users be able to do? It seems that this choice is only available if I am building the ASP.NET page on my "localhost". So that is the first problem. So I am able to get the pages to work, atleast the things such as the textboxes to show up etc, (Even things as advanced as the "Login" box). How ever when I try to get someone to try to login I am taken to a page that has an server error. The error is:
"The SSE Provider did not find the database file specified in the connection string. At the configured trust level (below High trust level), the SSE provider can not automatically create the database file. "
The Stack Trace Errors are at the bottom. I think this is happening because the automatically generated databases are not getting built online as they are on my computer. On my computer I have MSSQL express. So either the databases are not getting built for some reason, (and I think that is the case as I don't see any in the folder). So I think that somehow I have to create a database on my server, and then somehow configure the ASP.NET file, perhaps in the Web.Config file to look for that new database. Is this the correct methodology? Is there some simpler way that I can just somehow upload things as they are and have them work correctly on my server? The error says that either the Server did not find the database or that the trust level was insufficient. I don't think that is it as I just looked again and I don't see any .MDF files. So how would I go about getting this to work right? Is there a way to do this with MySQL also? So that I don't have to use MSSQL? My server only allows 1 DataBase for that.
Thanks and I hope my question makes sense. It is basically how can I get it to be able to create and check users etc. online?
Brian
[ProviderException: The SSE Provider did not find the database file specified in the connection string. At the configured trust level (below High trust level), the SSE provider can not automatically create the database file.] System.Web.DataAccess.SqlConnectionHelper.EnsureSqlExpressDBFile(String connectionString) +2555237 System.Web.DataAccess.SqlConnectionHelper.GetConnection(String connectionString, Boolean revertImpersonation) +87 System.Web.Security.SqlMembershipProvider.GetPasswordWithFormat(String username, Boolean updateLastLoginActivityDate, Int32& status, String& password, Int32& passwordFormat, String& passwordSalt, Int32& failedPasswordAttemptCount, Int32& failedPasswordAnswerAttemptCount, Boolean& isApproved, DateTime& lastLoginDate, DateTime& lastActivityDate) +1121 System.Web.Security.SqlMembershipProvider.CheckPassword(String username, String password, Boolean updateLastLoginActivityDate, Boolean failIfNotApproved, String& salt, Int32& passwordFormat) +105 System.Web.Security.SqlMembershipProvider.CheckPassword(String username, String password, Boolean updateLastLoginActivityDate, Boolean failIfNotApproved) +42 System.Web.Security.SqlMembershipProvider.ValidateUser(String username, String password) +83 System.Web.UI.WebControls.Login.OnAuthenticate(AuthenticateEventArgs e) +160 System.Web.UI.WebControls.Login.AttemptLogin() +105 System.Web.UI.WebControls.Login.OnBubbleEvent(Object source, EventArgs e) +99 System.Web.UI.Control.RaiseBubbleEvent(Object source, EventArgs args) +35 System.Web.UI.WebControls.Button.OnCommand(CommandEventArgs e) +115 System.Web.UI.WebControls.Button.RaisePostBackEvent(String eventArgument) +163 System.Web.UI.WebControls.Button.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument) +7 System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) +11 System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData) +33 System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +5102
Can someone help me with the following problem:
I'm a SQL server DBA and we sell intern SQL-Server resources to the application teams based on needed storage and number of users.
I have several servers shared by different application teams.
Now I'm looking for a method to limit the number of users working together on a specified Database. Because when a project manager wants resources for 100 users I want to be sure that only 100 users can connect to that particular database at the same time.
I know I can limit the number of connections on server level but I need this on Db level too.
Can someone help me?
Is there any way to confirm the isolation level of a given connection from outside of the connection itself?
As far as I can see, DBCC USEROPTIONS only returns information regarding the current connection.
I am troubleshooting a locking issue and it would be very helpful to me if I could check the isolation level of any given connection.
Thanks in advance for any help.
I need to pass a application userid on every call to my database for triggers on the db to use.
I am connecting to my database using integrated security from my application, all on one windows domain account. However I need to get an application user id over on the connection for triggers to use to stamp in changelogs.
Currently everytime we open a connection we create a #table with the user id in it, but that is expensive, especially in our new SOA where connections are frequently created and dropped on requests.
Is there any way I can get a connection level variable over to the database server so triggers could read it?
Any help is greatly appreciated.
We have a need for getting data from sqlserver DB on premise to the cloud. DB is not encrypted currently, other applications are accessing it but those applications are on premise. Following link talks about encrypted connection, but is it possible to encrypt only one of the port connection. we can add a custom port.URL...
View 3 Replies View RelatedWhen I deploy the cube which is sitting on my PC (local) the following 4 errors come up:
Error 1 The datasource , 'AdventureWorksDW', contains an ImpersonationMode that that is not supported for processing operations. 0 0
Error 2 Errors in the high-level relational engine. A connection could not be made to the data source with the DataSourceID of 'Adventure Works DW', Name of 'AdventureWorksDW'. 0 0
Error 3 Errors in the OLAP storage engine: An error occurred while the dimension, with the ID of 'Customer', Name of 'Customer' was being processed. 0 0
Error 4 Errors in the OLAP storage engine: An error occurred while the 'Customer Alternate Key' attribute of the 'Customer' dimension from the 'Analysis Services Tutorial' database was being processed. 0 0
I want to perform column level and database level encryption/decryption....
Does any body have that code written in C# or VB.NET for AES-128, AES-192, AES-256 algorithms...
I have got code for single string... but i want to encrypt/decrypt columns and sometimes the whole database...
Can anybody help me out...
If you have Store procedure in SQL for the same then also it ll do...
Thanks in advance
Hi,
AM in need of SSRS 2005 design documents for a project purpose. Can somebody let me know where can i find these documents? Thanks in advance
I need some help to under stand when the right time is for NOLOCK. I work in a small dev group and NOLOCK seams to be a buzz word and others are throwing it in all over for no apparent reason.
I read the thing from http://www.sql-server-performance.com/ and I am sure that our web and SQL servers are about 100x over sized for the application. While are ASP.Net (VB) app may demonstrate some hesitation from time to time I am more inclined to blame poor VB.Net coding techniques before slow SQL. The point being the NOLOCK is being added to SELECTS that are not part of a transaction and were using the SQL data adapter to return datasets or single column values.
Also I am not even sure it’s being used correctly. The OLM has the example:
SELECT au_lname FROM authors WITH (NOLOCK)
However I am seeing it formatted like this:
SELECT au_lname FROM authors (NOLOCK)
I am by no mean an expert, I follow what I read in books or from examples from others. And I have never read in a book go crazy with NOLOCK because it’s the bomb!
Any thoughts? I am trying to learn as much as I can before I raise my hand and say this might be a bad idea.
Thanks
Other than "dirty" reads, what are the cons of using NOLOCK throughout a query?
View 1 Replies View RelatedHi,
I have a job that runs 3 seperate DTS packages.
The first step imports a file and runs successfully.
The second step which is the 2nd DTS package is hanging in the execute mode until I manually stop the job. Apparently,We discovered a bulk insert that is blocking a select statement--both proccesses are within this second DTS package. I tried using the WITH (UNLOCK) on the tables but this DTS package is still failing.
Does anyone have any suggestion? It would be greatly appreciated.
Hi guys,
I am a new user for DB2.
In DB2 V8, i have a table with some no of columns.
table test
col1
col2
col3
col4
Now i want to issue a query like this.
select col1 from test with(NOLOCK) where col1 = <some value>
when i am executing this query on that time i am getting a error message like this...
SQL0158N The number of columns specified for "MT.TEST" is not the
same as the number of columns in the result table. SQLSTATE=42811
Anyone can help me???
i tried to find out.
I did the same thing with SQL server 2000.
I am not facing any problem there.
Thanks & Regards,
Muthu
Paul Randal,
There has been a discussion/debate going on this thread about the benefits and drawbacks of using the NOLOCK hint:
http://www.sqlteam.com/forums/topic.asp?TOPIC_ID=67294
It occurred to me that you might know more about this than any of us, or at least be able to point us to a white paper or knowledge base article that explains the subject in more detail. Any light you can shed on the subject would be a big help.
CODO ERGO SUM
is really helpful use "with (nolock)" sentence in selects??
100% useful?? disadvantages?
best regards
Joseph
Hello,
Does anyone know if you place NOLOCK after a view in a select statement, if the effects trickle down to the tables in the view? Or does one have to add NOLOCK to each table within the view?
Thanks
Hello !!
I'm using the sentence NOLOCK for selects, but I have many sentences, Is there any way to set a parameter in the DBMS, to use NOLOCK parameter by default ???? I mean, I don't like to lock any table for selects.
Is It possible ???? How to do It (step by step) ?
Thanks !!
Hey guys,
I came across a SQL statement, thought up by a developer, in which two views were joined with the NOLOCK hint:
SELECT v1.xxx, v2.yyy
FROM dbo.vw_SomeView v1 WITH (NOLOCK)
INNER JOIN dbo.vw_SomeOtherView WITH (NOLOCK) ON v1.id = v2.id
The views are not created the NOLOCK hint. So my question is: has the NOLOCK hint any effect here?
I've looked in the BOL and searched on the net but can't find anything on this particular topic.
Lex
PS. Personally I don't like to use views in JOINs. I've seen too many cases in which tables are joined twice just because they are part of both views. Further more I don't like the "random" use of NOLOCK because most people don't seem to understand the implications of it. But this is besides the point of my question ;)
I'm running a heavy SELECT query using WITH (NOLOCK). This still causes other processes trying to INSERT in one of the tables to get blocked.
I thought the locking hint would prevent from blocking other processes?
What will happen if I'm running a query with the NOLOCK hint but the SQL Server has run out of resources?
Thanks!
Hi,
I was sreading about NOLOCK that it could prevent deadlocks but could return data which is not committed yet.
1) Should we use NOLOCK with select statements
2) If the transaction isolation level is set appropriately (e.g. Serializable)in the component (for e.g COM+ component) but NOLOCK is specified in the select then would it return uncommitted data. I mean if the transaction is controlled at hihger level then what will be the Pros and Cons of using NOLOCK.
Thanks
What is the purpose of using WITH(NOLOCK)?
View 3 Replies View RelatedHi!
select * from rubberstock_tbl_shoppingcarttemp
It dosent take datas from the table but
select * from rubberstock_tbl_shoppingcarttemp (nolock)
This querey takes the data from the table
what can i do to retrieve records through first query.I dont know what
is happening please explain and also dont know about nolock
Thanks in advance!
When the NOLOCK hint is included in a SELECT statement, no locks are taken when data is read. This gives a Dirty Read in a result set.
The data retrieved in the select statement may not be correct since some other process might have updated the data while it was taken in the select statement.
Now, Can I know what is the use of NOLOCK? In which way we can make efficient use of NOLOCK ???
Hi, I get an error when select * from a table with nolock....please help.
Cannot specify an index or locking hint for a remote data source
Hi,
I have never used NOLOCK, or ROWLOCK, or anything of that sort. It's something I thought was over my head when I first encountered it and as I am gaining a better grip on SQL I have decided I want to try and tackle it. Also, because I think its causing me some problems :)
I recently implemented a new query into my application.
The query below gets the COUNT(*) of certain tables. Some of these tables are tall (5 million plus rows)
The counts returned are not absolutely critical information, and we are not joining or doing any other transactions based on this data. I believe running these counts on these pretty active tables (selects,inserts) are possibly causing slowdowns ?
Would using NOLOCK be an appropriate situation for something like this ? I am looking for a performance increase hopefully, and hoping there isnt much of a downside? I'm also not sure what type of reliability to expect from NOLOCK.
Any help much appreciated !!
Thanks once again
mike123
create PROCEDURE [dbo].[select_UserStats_Admin_TEST]
(
@userID int
)
AS SET NOCOUNT ON
DECLARE @Mail_Sent INT, @Mail_Received INT, @Comments_Sent INT, @Comments_Received INT,
@friendsListCount INT
SELECT @Mail_Sent = count(*) FROM tblMessage WHERE messageFrom = @userID
SELECT @Mail_Received = count(*) FROM tblMessage WHERE messageTo = @userID
SELECT @Comments_Sent = count(*) FROM tblComment WHERE CommentFromID = @userID
SELECT @Comments_Received = count(*) FROM tblComment WHERE CommentTo = @userID
SELECT @friendsListCount = count(*) FROM tblFriends WHERE userID = @userID
SELECT @Mail_Sent as Mail_Sent, @Mail_Received as Mail_Received, @Comments_Sent as Comments_Sent,
@Comments_Received as Comments_Received, @friendsListCount as friendsListCount
Hi,Is there a way to catch every select comming to sql and change it toselect with nolock?or how to make database READ UNCOMMITTED permanent?any ideas?Richard
View 3 Replies View RelatedI am getting lot of deadlocks in my application. As it is very complexti avoid deadlocks at this stage of application we have done few stepsto lessen the impact.We have added retries after deadlock is capturted.We have added select * from TABLE with (nolock) wherever possible.But interestingly second step is not working. I have few simple selectstatements where i am using nolock criteria still I am gettingdeadlock victim error. Any idead why it happening. I thought as soonas I put nolock in the query it will ignore all the locks.My sp isCREATE procedure sp_Check_denomination@supply_till_idint,@product_codechar(4),@iso_currency_codechar(3),@denominationmoneyasdeclare @product_id numeric(5)select @product_id = product_id from product with (nolock) whereproduct_code = @product_codeif exists (select *from transaction_inventory TI with (nolock),product_ccy_denom PCD with (nolock)where TI.supply_till_id = @supply_till_idand TI.product_id = @product_idand TI.iso_currency_code= @iso_currency_codeand TI.denomination = @denominationand TI.product_id = PCD.product_idand TI.iso_currency_code = PCD.iso_currency_codeand TI.denomination = PCD.denominationand PCD.product_id=@product_idand PCD.denomination = @denominationand PCD.iso_currency_code=@iso_currency_codeand PCD.tradeable = 1)beginreturn(1)endelsebeginreturn(0)endGO
View 1 Replies View RelatedBackground: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!
View 2 Replies View RelatedIs the NOLOCK optimizer hint being deprecated? Or does this apply only to use of NOLOCK in UPDATE and DELETE statements or what exactly?
I can see that in this article that there are circumstances in which the hint is deprecated; however, I have developers that are acting like NOLOCK is about to be dropped entirely. As far as I know, that is not the case but I would definitely like some feedback on this.
I have been experiencing deadlock errors with two stored procs that I am using.
SP1 is a read query that gets all unprocessed orders (status = 0)
SP2 is an insert query that inserts new orders (Status = 0) uses a transaction.
I have a multithreaded application and once in a while the read query (SP1) will try to read a new row that has just been inserted but not committed yet hence the deadlock arises.
If i use a hint "With(NoLocks)" this will be a dirty read and still read the uncommitted insert from SP2 - is this correct?
Where as if I use hint "With(ReadPast)" this will now only read committed rows and hence the deadlock should not arise - it will not read any uncommitted rows - Correct?
So I think that it is better to use READPAST than NOLOCK. Any orders that have status = 0 not picked up will get picked up on the next round when SP1 is executed again.
Any thougths or suggestions are always appreciated.
Jawahar