PeopleSoft Adoption Made Smooth & Simple!
On-The-Job Training Is made Intuitive & Easy With WalkMe's On-Screen Guidance Tool. Claim Your Free WalkMe Account Now
Course Of The Month
4 days, 23 hours left to enrollBecome a Premium Member and unlock a new, free course in leading technologies each month.
Solved
Applying constraints to a large table
Posted on 2016-08-04
I Have had to rebuild a database for a customer and whilst most of this process has worked well I have come up against a problem. On three tables when I run code similar to that below:
It is taking an inordinate amount of time to do 6 million rows. Is there a way top improve this performance?
The SQL SERVER 2012 installation is on a virtual server which I have no administrative rights to and the customer has fairly limited IT resources too.
IF NOT EXISTS (SELECT * FROM sys.foreign_keys WHERE object_id = OBJECT_ID(N'[FK_GroupUserMap_User]') AND parent_object_id = OBJECT_ID(N'[GroupUserMap]'))
ALTER TABLE [GroupUserMap] WITH NOCHECK ADD CONSTRAINT [FK_GroupUserMap_User] FOREIGN KEY([UserInfoKey])
REFERENCES [UserInfo] ([UserInfoKey])
It is taking an inordinate amount of time to do 6 million rows. Is there a way top improve this performance?
The SQL SERVER 2012 installation is on a virtual server which I have no administrative rights to and the customer has fairly limited IT resources too.
[X]
Welcome to Experts Exchange
Add your voice to the tech community where 5M+ people just like you are talking about what matters.
- Help others & share knowledge
- Earn cash & points
- Learn & ask questions
-
3
2
- +1
7 Comments
Active 3 days ago
Why? The existence of the foreign key is not checked for 6 million rows but only a few rows of metadata in sys.foreign_keys and since your alter table adds a constraint with NOCHECK, this shouldn't take long, as it doesn't check the 6 million rows.
If anything does take long, then it's not this code but something else you don't show here.
Bye, Olaf.
If anything does take long, then it's not this code but something else you don't show here.
Bye, Olaf.
Hey Olaf
That was my thoughts, but there is nothing else in the script that affects this code just more of the same. and yet it runs for a weekend and no completion :( I have pretty much read around the subject as completely is I think possible I am hoping someone else has had a similar problem and found a solution.
That was my thoughts, but there is nothing else in the script that affects this code just more of the same. and yet it runs for a weekend and no completion :( I have pretty much read around the subject as completely is I think possible I am hoping someone else has had a similar problem and found a solution.
Active 3 days ago
Sure, you don't end with something like ALTER TABLE table WITH CHECK CHECK CONSTRAINT ALL?
I still stand to this, a constraint added with NOCHECK does not check rows, so the size of the table will not matter. You need to look for something else.
Bye, Olaf.
I still stand to this, a constraint added with NOCHECK does not check rows, so the size of the table will not matter. You need to look for something else.
Bye, Olaf.
No Olaf I highlighted the code as written and execute it and I agree with you, I was hoping for someone to have had this experience and found a way around it. That may never happen, I just need to give this a fair amount of time before I decide what to do next.
Active 1 day ago
There must be a lock involved. I recommend you to install Adam Machanic's sp_whoisactive stored procedure and while you run that ALTER statement in a separate query window you will execute :
EXEC sp_whoisactive
and check for the blocking_session_id column. If there is a session_id in that column in the row that shows your ALTER statement then you will have to kill/terminate that process.
Here is the procedcure:
http://sqlblog.com/blogs/adam_machanic/archive/2012/03/22/released-who-is-active-v11-11.aspx
Download here: http://sqlblog.com/files/folders/beta/entry42453.aspx
It is free.
EXEC sp_whoisactive
and check for the blocking_session_id column. If there is a session_id in that column in the row that shows your ALTER statement then you will have to kill/terminate that process.
Here is the procedcure:
http://sqlblog.com/blogs/adam_machanic/archive/2012/03/22/released-who-is-active-v11-11.aspx
Download here: http://sqlblog.com/files/folders/beta/entry42453.aspx
It is free.
Active today
A lock should be a good explanation but what make a table to be locked for a full weekend?
Do you have any job running? Something like an Import/Export or even a maintenance job scheduled for weekends?
Also if you don't want to use sp_WhoIsActive you can use the built in sp_who2 and check for the rows with blocked column <> 0.
Do you have any job running? Something like an Import/Export or even a maintenance job scheduled for weekends?
Also if you don't want to use sp_WhoIsActive you can use the built in sp_who2 and check for the rows with blocked column <> 0.
Featured Post
Learn about Edgartown's quest to ensure the safety and security of the entire town's employee and citizen data. Read the case study!
Question has a verified solution.
If you are experiencing a similar issue, please ask a related question
Load balancing is the method of dividing the total amount of work performed by one computer between two or more computers. Its aim is to get more work done in the same amount of time, ensuring that all the users get served faster.
International Data Corporation (IDC) prognosticates that before the current the year gets over disbursing on IT framework products to be sent in cloud environs will be $37.1B.
Familiarize people with the process of utilizing SQL Server functions from within Microsoft Access. Microsoft Access is a very powerful client/server development tool. One of the SQL Server objects that you can interact with from within Microsoft Ac…
This video shows how to set up a shell script to accept a positional parameter when called, pass that to a SQL script, accept the output from the statement back and then manipulate it in the Shell.
Suggested Courses
Course of the Month4 days, 23 hours left to enroll
688 members asked questions and received personalized solutions in the past 7 days.
Join the community of 500,000 technology professionals and ask your questions.