Kathi Kellenberger

Kathi Kellenberger is a Sr. Consultant with Pragmatic Works. She is an author, speaker and trainer.
  • Interests: Walking, running, grandchildren!

SQLServerCentral Editorial

Query Tuning Assistant: A Tool for Upgrades

If you have been working with SQL Server long enough, you have probably been involved with a SQL Server 2000 to 2005 upgrade. It was painful for many shops due to the deprecation of some features like DTS and the removal of old-fashioned comma joins with the plus operator. It was worth the pain as […]

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2019-03-25

1,225 reads

SQLServerCentral Editorial

Doing the Right Thing

From the time you rise in the morning until you close your eyes at night, your day is filled with thousands of small decisions, many that you don’t even think about. For each decision that you make, there is a probably a good choice and a poor choice available. Most of the time, the good […]

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2019-01-28

139 reads

SQLServerCentral Editorial

PASS Summit 2018 Recap

This year, PASS celebrated the 20th PASS Summit. As it has been many times, this year’s Summit was held in Seattle. PASS Summit has visited other locations such as Orlando and Charlotte, but, at least to me, it feels like home when it’s hosted in Seattle. For those of us who have participated for many […]

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2018-11-19

36 reads

SQLServerCentral Editorial

Explaining Our Professions to Our Parents

Have you ever had a difficult time explaining what your job entails to your parents or other family members? You may be working in a field that didn’t exist 20 years ago, such as mobile device development, or your job may be so specialized that non-technical people will never understand. Now that my job title […]

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2018-11-05

93 reads

SQLServerCentral Editorial

What Should You Look for in a SQL Monitoring Tool?

Performance is a common reason to monitor SQL Server. The work day of a database administrator is often interrupted with unexpected calls about slowness in applications or reports. But, how does the performance today compare to the performance last week or last month? Can the root cause of the issue be traced to the database […]

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2018-10-08

43 reads

SQLServerCentral Editorial

SQL Server Gets Smarter and Smarter

With each recent version of SQL Server, Microsoft has added features that can be used to improve query performance with much less effort than traditional index and query tuning require. First was Query Store, introduced with 2016. When enabled, this feature allows you to easily find regression in query performance due to changing execution plans. […]

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2018-05-21

77 reads

SQLServerCentral Editorial

SQL Community

Back in my early days as a database administrator, almost 16 years ago, I happened upon a web site called SQL Server Central. Because I found so many useful articles and forum posts, the site was open in my browser at work every single day. It was a great source of information, and eventually, I […]

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2018-04-23

96 reads

Blogs

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Refactoring SQL Code

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Comments posted to this topic are about the item Refactoring SQL Code, which is...

The Read Committed Snapshot Isolation behaviour

By Alessandro Mortola

Comments posted to this topic are about the item The Read Committed Snapshot Isolation...

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By sabyda

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Question of the Day

The Read Committed Snapshot Isolation behaviour

I am currently working with Sql Server 2022 and AdventureWorks database. First of all, let's set the "Read Committed Snapshot" to ON:

use master;
go

alter database AdventureWorks set read_committed_snapshot on with no_wait;
go
Then, from Session 1, I execute the following code:
--Session 1
use AdventureWorks;
go

create table ##t1 (id int, f1 varchar(10));
go

insert into ##t1 values (1, 'A');
From another session, called Session 2, I open a transaction and execute the following update:
--Session 2
use AdventureWorks;
go

begin tran;
update ##t1 
set f1 = 'B'
where id = 1;
Now, going back to Session 1, what happens if I execute this statement?
--Session 1
select f1
from ##t1
where id = 1;
 

See possible answers