Dallas DBAs

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SQL Server Wait Stats

Everything in SQL Server is waiting for something…this is by design. And most people never think about it… Until your application is waiting to complete its request, sell the...

2025-04-30 (first published: )

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The Cost of Not Having a DBA

Does skipping a DBA save money? Wait until your system grinds to a halt, your backups fail, or your cloud bill skyrockets. The “DBA? We Don’t Need No Stinkin’...

2025-04-14 (first published: )

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Blog Post

SQL Server Time Bombs

Common Reasons for Emergency SQL calls If you are a production DBA (or Accidental prod DBA) you’ve gotten that frantic call in the middle of the night. Or maybe...

2025-03-12 (first published: )

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Blog Post

Top 10 Careers in Data

Would you re-order these? Machine Learning Engineer $$$$$ Develop and deploy AI models Optimize machine learning algorithms for efficiency Work with big data frameworks to process large datasets Data...

2025-02-28 (first published: )

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Blog Post

Degrees and Trade Schools

Can we normalize a couple of things? 1 – Trade Schools. Back in the 80’s trade classes in high school and post high school were frowned upon, or looked...

2024-05-08

27 reads

Blogs

Why Optimize CPU for RDS SQL Server is a game changer

By

One feature that I have been waiting for years! The new announcement around optimize...

Performance tuning KubeVirt for SQL Server

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Following on from my last post about Getting Started With KubeVirt & SQL Server,...

T-SQL Tuesday #193 – A Note to Your Past, and a Warning from Your Future

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I haven’t posted in a while (well, not here at least since I’ve been...

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Refactoring SQL Code

By Steve Jones - SSC Editor

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...

Working with JSON/JSONB Data in PostgreSQL using Python

By sabyda

Comments posted to this topic are about the item Working with JSON/JSONB Data in...

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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;
 

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