18 Responses to Free Poster! Guide to SQL Server Isolation Levels

  1. Brian Garraty February 8, 2011 at 9:50 am #

    Wow… that is awesome. Great job!

  2. Kimberly L. Tripp February 8, 2011 at 10:07 am #

    Love it!

    And, I like the presentation as well. Must have been a fun one to do!

    One thing that’s cool is that you show how the BookName index helps serializable reduce the locks required (to key-range locking). This is cool to really hit home the problem that without it SQL Server has to use table-level locks. This always surprises people.

    Regardless, cool (and fun) example/deck!


  3. Yanni Robel February 8, 2011 at 4:35 pm #

    Awesome poster and great slide deck! I just sent the link of your blog to my dev team, especially the slide deck so they can read it themselves!

    Great job!

  4. John Sansom February 10, 2011 at 4:59 am #

    Dang I always knew SQL could be cool.

  5. CFRandall February 11, 2011 at 8:50 am #


    • Joe Bruno February 14, 2011 at 10:11 am #

      Thank you so much Kendra! I love the poster and I learned a ton at your SQL Saturday Cleveland presentations on Isolation and Partitioning.

      • Kendra Little February 17, 2011 at 8:22 am #

        Very cool! I had a great time giving the talk and the audience was really great. The presentation gave me some ideas to restructure the slides a bit and maybe automate some demos, but that just means I had such a good time that I’d like to make it even better.

  6. Greg Faulk February 17, 2011 at 11:39 am #

    Shouldn’t the “still a bit pessimistic” label have been applied to Read Committed since Read Uncommitted is the lowest level? In other words how is Read Uncommitted more pessimistic than Read Committed? In any case I’m forwarding both the poster and slide deck to some of our developers. Your presentation is much easier to grasp than BOL. Thanks.

    • Kendra Little February 17, 2011 at 11:53 am #

      Good point– it’s meant to show Most Pessimistic to Least Pessimistic in clockwise order.

      I should indeed move that comment over to the other arrow, because I put in the comment about schema stability locks below Read Uncommitted (which is really what I wanted to convey about it and locking). And maybe that’ll leave room for a note that Read Uncommitted sometimes uses an allocation order scan!

  7. Ameena Lalani March 3, 2011 at 9:26 am #

    This poster is not only informational but very cool also. I have printed it and displayed in my cubicle. I look a bit smarter now. 🙂

    • Kendra Little March 7, 2011 at 8:47 pm #

      What an awesome thing to say! Now I feel a bit cooler 🙂


  8. Rowland Gosling March 16, 2011 at 7:19 am #

    Tres cool Kendra! I need to print this off and share it with my team 🙂 I think I’ll blog about it too–how did I miss this?!

  9. Robert L Davis April 22, 2011 at 10:15 am #

    I wish I had mad skills like drawing or fighting with nunchucks!!

  10. Eric March 2, 2012 at 12:12 pm #

    Wow this is hard to find from the front page of your blog now! Had to search. I’ve read this poster & sent many people to it since a developer pal clued me in last year. I just freaked out thinking it was gone… Front page material for sure!

    • Kendra Little March 2, 2012 at 12:30 pm #

      Hi Eric,

      I’m trying to get all my content moved over to BrentOzar.com for downloads. There’s an old George Carlin skit I’m trying to follow about having all that sutff in one place. 🙂

      Thanks for letting me know that people are still looking here for this, I’ll put up some links!


  1. Tweets that mention Free Poster! Guide to SQL Server Isolation Levels | LittleKendra.com -- Topsy.com - February 8, 2011

    […] This post was mentioned on Twitter by Brent Ozar, Jeremiah Peschka, Jeremy, ravikanth, Bill Fellows and others. Bill Fellows said: #awesomesauce RT @Kendra_Little: [Blogged] Free Poster – Isolation levels in SQL Server http://bit.ly/fOdS3d #sqlblog […]

  2. Something for the Weekend – SQL Server Links 11/02/11 | John Sansom - SQL Server DBA in the UK - February 11, 2011

    […] Free Poster! Guide to SQL Server Isolation Levels – Artistic flair from Kendra Little. […]

  3. Eric Humphrey » NOLOCK for Developers - March 25, 2011

    […] Little (blog | twitter) made up a poster that helps visualize the different isolation levels. She also put together a great list of links […]

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