I'm speaking at PASS Data Community Summit 2022

Looking forward to speaking in Seattle at next week's PASS Data Community Summit by Redgate. I'll be speaking both as a representative of my role on the Microsoft Database Docs team and as a data professional. 

On Wednesday Nov 16, you'll find me in the main exhibit hall in the Microsoft Booth Theater (#217) giving a presentation on contributing to Microsoft Docs, at 530pmPT. Hope to see you there. If prizes are available to give away, you know I'll give em up.

On Thursday afternoon, Christine and I are presenting together on a topic that is important to us, Ethics in Modern Data. I bring my years as a data professional and Christine brings her experience and a Masters degree in Organization Psychology, combined with our passion for history, civil rights, and technology. We'll be discussing issues ripped from the news headlines and in history. These will frame a discussion about bias in data collection and analysis, and our responsibilities as data professionals. I hope we spark your interest in these important topics that shape our data industry.

On Friday morning, I'll be presenting a full hour on Database Docs. We'll discuss how they work behind the scenes and how you can contribute to open-source docs via GitHub. This will also be an interactive feedback panel for the entire Docs platform inside Microsoft Learn. Hope to see you there, inspire you to contribute to the Docs that the entire data community uses daily, and answer any questions.

A simple lab to demonstrate the danger of NOLOCKs in INSERT statements

The READ UNCOMMITTED isolation level, which the NOLOCK table hint activates, is not to be trusted when it comes to writing data. You are not always protected by error 1065 in cases where writes meet NOLOCK. 

Error 1065 states "The NOLOCK and READUNCOMMITTED lock hints are not allowed for target tables of INSERT, UPDATE, DELETE or MERGE statements."  However, NOLOCK can still dangerously be used as the source of the write. (NOLOCK can also fail with error 601 on even basic SELECT statements, but coders just aren't always scared off by that.)

Here's a very elementary example to share at parties in order to scare developers away from using NOLOCKs adventurously:

--Connection 1
DROP TABLE IF EXISTS dbo.testnolock1
GO
CREATE TABLE dbo.testnolock1
(id int not null IDENTITY (1,1) PRIMARY KEY,
text1 varchar(10) not null
)
GO
INSERT INTO dbo.testnolock1 (text1) VALUES (1);
GO

Now we have a table with 1 row. Let's begin a transaction to insert another row, but not commit it.

--Connection 1
BEGIN TRAN
INSERT INTO dbo.testnolock1 (text1) VALUES (2); 

And in a second table, let's do an INSERT based on a SELECT statement with the NOLOCK table hint.

--Connection 2
DROP TABLE IF EXISTS dbo.testnolock2
GO
CREATE TABLE dbo.testnolock2
(id int not null IDENTITY (1,1) PRIMARY KEY,
text1 varchar(10) not null
)
GO
INSERT INTO testnolock2
SELECT TEXT1 FROM testnolock1 (NOLOCK)

Without the NOLOCK hint, would be blocked by the INSERT in progress in Connection 1. 

With the NOLOCK hint, the INSERT statement in Connection 2 completes immediately...  however, back in Connection 1:

--Connection 1
ROLLBACK TRAN

What have we got now? From any connection:

SELECT * FROM testnolock1;
SELECT * FROM testnolock2;

One row in testnolock1, two rows in testnolock2

While the INSERT into testnolock1 rolled back (because of one of many different transient errors or failures, not just due to a ROLLBACK), the INSERT with the doomed row where text1=2 succeeded just fine in testnolock2. This is bad! Should Connection 1 retry its INSERT, we could have duplicated data, primary key violations, etc.

If this seems basic to you, great! You have a healthy understanding and fear of the chaos that NOLOCK can unleash. 

SQLSaturday Baton Rouge is back!

Looking forward to jambalaya at #SQLSatBR in THIS SATURDAY! Also looking forward to speaking and seeing all of you there, I guess... Register today: https://sqlsaturday.com/2022-08-06-sqlsaturday1026/

After I stepped down from the SQLSaturday Baton Rouge organizing committee lead in 2019, I had no idea what was to come. A pandemic, the dissolution of SQL PASS, and two missed Augusts later, SQLSaturday Baton Rouge is back! One thing I did get right in 2019: other volunteers deserved the chance to lead and organize and network and they've been doing a great job, from what I can tell so far. I'm happy to see the assets and resources we'd built together over 11 years of SQLSaturdays at LSU continue to be put to use.

I am speaking at:

- 9:45am in the Careers in IT panel

- 11am for Tabletop Role-playing Games at Work for Fun & Profit with Stacy Vicknair and Christine Assaf - Presentation available for download

- 1:30pm for How to Think Like a Certification Exam - Presentation available for download

See you there!