Physical Join Operators in SQL Server - Hash Operator
In the concluding part of the Physical Operators series we look at the Hash operator.
2010-07-12
3,790 reads
Execution Plans
Physical Join Operators in SQL Server - Merge Operator
Part II of the Physical Joins series looks at the Merge operator.
2010-07-05
4,112 reads
Operator of the Week - Lazy Spool
Continuing to illuminate the depths of SQL Server's Query Optimizer, Fabiano shines a light on the sixth major Showplan Operator on his list: the Lazy Spool. What does the Lazy Spool do that's so special, how does the Query Optimizer use it, and why is it so Lazy? Fabiano Amorim explains all.
2010-06-28
2,774 reads
Controlling Execution Plans with Hints
The Query Optimizer gets it right most of the time, but occasionally it chooses a plan that isn't the best possible. You can give the Query Optimiser a better idea by using Table, Join and Query hints. These come with a risk: Any choices you force on the Optimizer by using hints can turn out to be entirely wrong as the database changes with the addition of data over time. Grant Fritchey, in a chapter from his highly acclaimed book, explains further.
2009-11-25
3,275 reads
2009-04-24
3,405 reads
Analyzing the SQL Server Plan Cache
Keeping in mind the importance of the cache mechanism, how could one get the plans and their usage statistics in SQL Server?
2009-01-19
4,183 reads
Graphical Execution Plans for Simple SQL Queries
Learning how to read and analyze execution plans takes time and effort. But once you gain some experience, you will find them an essential skill for getting to grips with performance issues in SQL Server Queries. Grant here describes the range of execution plans for different simple SQL Queries.
2009-01-05
5,326 reads
Blogs
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Forums
What is the Cloud?
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Changing the Schema
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Index Fragmentation Explained: Page Splits, Logical Reads, and What to Do
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Question of the Day
Changing the Schema
I set up a few users on my SQL Server 2022 instance.
CREATE LOGIN User1 WITH PASSWORD = 'Demo12#1' CREATE USER User1 FOR LOGIN User1 GO CREATE LOGIN User2 WITH PASSWORD = 'Demo12#2' CREATE USER User2 FOR LOGIN User2 GO CREATE LOGIN User3 WITH PASSWORD = 'Demo12#3' CREATE USER User3 FOR LOGIN User3 GOI then created a schema that one of them owned. Under this schema, I added a table with some data.
CREATE SCHEMA MySchema AUTHORIZATION User1
GO
CREATE TABLE Myschema.MyTable(myid INT)
GO
INSERT MySchema.MyTable
(
myid
)
VALUES
(1), (2), (3)
GO
SELECT * FROM MySchema.MyTable
GO
I granted rights and verified that User2 could access this table.
GRANT SELECT ON Myschema.MyTable TO User2 GO SETUSER 'USER2' GO SELECT * FROM MySchema.MyTable GOThis worked. Now, I move this schema to a new user.
ALTER AUTHORIZATION ON SCHEMA::Myschema TO User3; GOWhat happens with this code?
SETUSER 'USER2' GO SELECT * FROM MySchema.MyTable GOSee possible answers