James Serra's Blog

Blog Post

Power BI and a Star Schema

I sometimes get asked from customers if they should use a star schema or should they use one large single table/flatfile for their dataset in Power BI. The answer...

2021-03-05 (first published: )

998 reads

Blog Post

Data Mesh defined

The two latest trends in emerging data platform architectures are the Data Lakehouse (the subject of my last blog Data Lakehouse defined), and the Data Mesh, the subject of...

2021-02-19 (first published: )

808 reads

Blog Post

Data Mesh defined

The two latest trends in emerging data platform architectures are the Data Lakehouse (the subject of my last blog Data Lakehouse defined), and the Data Mesh, the subject of...

2021-02-16

9 reads

Blog Post

Data Lakehouse defined

As a follow-up to my blog Data Lakehouse & Synapse, I wanted to talk about the various definitions I am seeing about what a data lakehouse is, including a...

2021-02-02 (first published: )

595 reads

Blog Post

Syncing SQL databases

There are various ways to keep SQL Server databases and SQL Database/SQL Managed Instance (SQL MI) databases in-sync asynchronously that I will discuss in this blog. The main use...

2021-01-05 (first published: )

842 reads

Blogs

Advice I Like: Art

By

Superheroes and saints never make art. Only imperfect beings can make art because art...

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

By

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

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Forums

data type gets lost in data flow

By stan

Hi, in a simple oledb source->derived column->oledb destination    data flow, 2 of my...

i noticed the sqlhealth extende event is on by default , so can i reduce

By rajemessage 14195

hi, i noticed the sqlhealth extended event is on by default , and it...

New-AzSqlInstanceServerTrustCertificate - Failed and no clues

By BrainDonor

Using New-AzSqlInstanceServerTrustCertificate to import a certificate and get the message New-AzSqlInstanceServerTrustCertificate: Long running operation...

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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