Bypassing Blocking using NOLOCK

Blocking, like life, happens. Blocking is caused by locking and locks are good. We need locking to give us a transactionally consistent view of the world. But sometimes we need more speed and less consistentency, and for those times using NOLOCK (or it's alias READUNCOMMITTED) are a simple way to bypass the blocking. We'll show you how, just remember that with great power comes great responsibility.

Andy Warren is a software trainer focusing on SQL Server, a member of the PASS Board of Directors, and a principal in this site - SQLShare.com.

BAEE210825 on 1/19/2011

All your videos have poor audio quality. Please improve it.

Charlie Bruno on 1/19/2011

Excellent presentation. Very relevant. I appreciate these training lessons.

Ron Almquist on 1/19/2011

Could be very useful.

Kasey Wheeler on 1/19/2011

Are you sure that NOLOCK and READUNCOMMITED are the same? I must have missed something in the example...one showed KEN and the other showed ANDY. Oh well. Good video.

Mark Hathaway on 1/19/2011

Great video today.

Steve Harris on 1/19/2011

Are there any other reason as to why you would not want to use those hints.

Mick on 1/19/2011

At the end of the video, should have re-ran the uncommitted SQL line

linda on 1/20/2011

Very helpful

Andrea on 1/20/2011

not sure when not to use noloak

Gabor Balazs on 1/21/2011

We have seen two different "dirty" select. What is the diferrence between nolock and uncommitted?

Reza on 1/21/2011

N/A

Diana Dee on 1/21/2011

Do a video on snapshot isolation. Also, when I do this demo, I select a different row showing the lock to be a row lock, then I select from the locked row and show blocking in Activity Monitor.

fritz matthews on 1/21/2011

i think giving an example of when you might want to use a nolock would be helpfull. thanks

Eric on 1/31/2011

I've watched quite a few SQLShare videos, and I can honestly say that they are the greatest resource on the web for quickly getting up to speed on any SQL Server subject. Thank you. Also, I have a huge appreciation for Andy Warren's videos, as well as Plamen Ratchev's. Please keep up the good work! To me, your videos are worth more than gold.

Jason Yousef on 1/31/2011

Great Tip

Mike on 2/22/2011

very well organized presentation of the concept

Rich on 2/22/2011

Thanks for the video. Short and useful.

Terry on 5/10/2011

That was excellent!!

Ludwig on 5/23/2011

Exellent...more like this

manjeet on 2/23/2012

nice

boreddy21 on 1/21/2013

if we have video for all locks, that would be very use full.