I got burned today at a SQL Server Interview!

  • Grant Fritchey (3/5/2008)


    FWIW, I put two people through phone screens yesterday. Both had more than 8 years experience in SQL Server. Both were listed as senior level consultants. Neither could describe the difference between clustered and non-clustered indexes, the difference between a block and a deadlock, or list ANY of the causes for a stored procedure to recompile. It's a pretty [explitive] sad state of affairs.

    WOW!! That is very [multiple explitive] sad! Guess they were just developers and had no knowledge of the inner workings of the engine. But in my opinion they should know quite a bit about internals after working with the product for 8 years. Shows a complete lack of initiative and desire to improve to me. Unfortunately people like that give me a bad name. I have had several clients that were leery to bring me on because of poor experiences with other consultants. Thankfully I have some amazing references and then once I get in the door I can really show what a qualified consultant can do. I have quite frankly been stunned by the actions or inactions of other so called experts!!

    Best,
    Kevin G. Boles
    SQL Server Consultant
    SQL MVP 2007-2012
    TheSQLGuru on googles mail service

  • Grant Fritchey (3/5/2008)


    FWIW, I put two people through phone screens yesterday. Both had more than 8 years experience in SQL Server. Both were listed as senior level consultants. Neither could describe the difference between clustered and non-clustered indexes, the difference between a block and a deadlock, or list ANY of the causes for a stored procedure to recompile. It's a pretty [explitive] sad state of affairs.

    Gotta hate when you see this. I wonder if Oracle has the same problem. I think this is one of the issues with making SQL Server fairly easy to work with and administer. If you did not have the GUI, and I use it for most tasks, would these people be out there?

  • First, 100% on the honesty thing. I would detect you and not hire you. Moreover, I would add you to my personal file of "never hires". Just something for you to consider.

    > Q:What is an index? A: Clustered and non-clus.<

    Hmm, that doesn't really answer the q now, does it? After all, I didn't ask "What types of indexes are there?". You don't listen especially carefully, do you? 🙂

    > My take on stats is that you should have autoupdate on <

    Wrong. For a production system, especially, autoupdate should be off -- otherwise, SQL may chose to update the stats at a very bad time for performance. Issue the UPDATE STATISTICS command yourself during off hours.

    SQL DBA,SQL Server MVP(07, 08, 09) "It's a dog-eat-dog world, and I'm wearing Milk-Bone underwear." "Norm", on "Cheers". Also from "Cheers", from "Carla": "You need to know 3 things about Tortelli men: Tortelli men draw women like flies; Tortelli men treat women like flies; Tortelli men's brains are in their flies".

  • Gotta disagree with you on the autoupdate stats being off statement. There are indeed a few huge production systems out there where autoupdate should be disabled, and also warehouse situations where it is appropriate. But for the vast majority of SQL Server implementations out there they should leave it ON.

    Best,
    Kevin G. Boles
    SQL Server Consultant
    SQL MVP 2007-2012
    TheSQLGuru on googles mail service

  • TheSQLGuru (3/5/2008)


    Gotta disagree with you on the autoupdate stats being off statement. There are indeed a few huge production systems out there where autoupdate should be disabled, and also warehouse situations where it is appropriate. But for the vast majority of SQL Server implementations out there they should leave it ON.

    Agreed - especially since you don't have 100% control over when your data might be changing a lot (in most cases). I'm more of the school of thought to leave the auto-update on until such time as I find that it's causing a major perf issue, and even then - I would have to weight whether NOT auto-updating might be a bigger drag on perf... Bad stats cause a lot of issues...

    ----------------------------------------------------------------------------------
    Your lack of planning does not constitute an emergency on my part...unless you're my manager...or a director and above...or a really loud-spoken end-user..All right - what was my emergency again?

  • Yeah, I was thinking about posting the same thing. Accurate statistics are way too important for getting good execution plans.

    "The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood"
    - Theodore Roosevelt

    Author of:
    SQL Server Execution Plans
    SQL Server Query Performance Tuning

  • Grant Fritchey (3/5/2008)


    FWIW, I put two people through phone screens yesterday. Both had more than 8 years experience in SQL Server. Both were listed as senior level consultants. Neither could describe the difference between clustered and non-clustered indexes, the difference between a block and a deadlock, or list ANY of the causes for a stored procedure to recompile. It's a pretty [explitive] sad state of affairs.

    Wow... 8 years of experience doing what? Walking past the server room each day? You're right... that's just sad... first thing anyone learns about indexes in SQL 101 is the difference between Clustered and Non-Clustered indexes... I can understand some Developers maybe missing the other two questions, but not DBA's and not someone with 8 years of experience... not even Developers.

    --Jeff Moden


    RBAR is pronounced "ree-bar" and is a "Modenism" for Row-By-Agonizing-Row.
    First step towards the paradigm shift of writing Set Based code:
    ________Stop thinking about what you want to do to a ROW... think, instead, of what you want to do to a COLUMN.

    Change is inevitable... Change for the better is not.


    Helpful Links:
    How to post code problems
    How to Post Performance Problems
    Create a Tally Function (fnTally)

  • Interesting. I guess my concern is that if a (very) large table(s) need updated, you could see a significant hit to your performance from autoupdate of stats. Also, for (v)lt, you cannot increase the sampling size to get better stats if you leave it automatic as you definitely won't have time to do, say, a 50% or fullscan during the day (peak usage period).

    And for (very) small tables, the details of the query plan are not as important for performance. Although, if you wanted to, you could of course rebuild those periodically yourself during the day.

    SQL DBA,SQL Server MVP(07, 08, 09) "It's a dog-eat-dog world, and I'm wearing Milk-Bone underwear." "Norm", on "Cheers". Also from "Cheers", from "Carla": "You need to know 3 things about Tortelli men: Tortelli men draw women like flies; Tortelli men treat women like flies; Tortelli men's brains are in their flies".

  • Jeff Moden (3/5/2008)


    Grant Fritchey (3/5/2008)


    FWIW, I put two people through phone screens yesterday. Both had more than 8 years experience in SQL Server. Both were listed as senior level consultants. Neither could describe the difference between clustered and non-clustered indexes, the difference between a block and a deadlock, or list ANY of the causes for a stored procedure to recompile. It's a pretty [explitive] sad state of affairs.

    Wow... 8 years of experience doing what? Walking past the server room each day? You're right... that's just sad... first thing anyone learns about indexes in SQL 101 is the difference between Clustered and Non-Clustered indexes... I can understand some Developers maybe missing the other two questions, but not DBA's and not someone with 8 years of experience... not even Developers.

    Both of them knew how to do backups... Maybe that tells us where a healthy chunk of our industry's time is spent... But I find that upsetting as well.

    "The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood"
    - Theodore Roosevelt

    Author of:
    SQL Server Execution Plans
    SQL Server Query Performance Tuning

  • Should also remember that 8 years of experience does not always equate to 8 years of experience; it could be 1 year of experience 8 times.

    :hehe::cool:

  • Or in this case, six months experience repeated 16 times.

    Sorry, I'm frustrated. I've got stacks & stacks of interview sheets with little x's next to questions that people with more than two year's of experience should know. Starts to get a little wearing.

    "The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood"
    - Theodore Roosevelt

    Author of:
    SQL Server Execution Plans
    SQL Server Query Performance Tuning

  • That's for sure. I love "experts" who don't know how to tell what the current SQL activity on the box is.

    SQL DBA,SQL Server MVP(07, 08, 09) "It's a dog-eat-dog world, and I'm wearing Milk-Bone underwear." "Norm", on "Cheers". Also from "Cheers", from "Carla": "You need to know 3 things about Tortelli men: Tortelli men draw women like flies; Tortelli men treat women like flies; Tortelli men's brains are in their flies".

  • Jeff Moden (3/5/2008)


    Grant Fritchey (3/5/2008)


    FWIW, I put two people through phone screens yesterday. Both had more than 8 years experience in SQL Server. Both were listed as senior level consultants. Neither could describe the difference between clustered and non-clustered indexes, the difference between a block and a deadlock, or list ANY of the causes for a stored procedure to recompile. It's a pretty [explitive] sad state of affairs.

    Wow... 8 years of experience doing what? Walking past the server room each day? You're right... that's just sad... first thing anyone learns about indexes in SQL 101 is the difference between Clustered and Non-Clustered indexes... I can understand some Developers maybe missing the other two questions, but not DBA's and not someone with 8 years of experience... not even Developers.

    Some of that seems to go to the lack of "title purity", meaning you can essentially assign pretty much any old functions to any old title, and come up with a DBA title for some doing nothing of the sort. I still remember walking into smaller places, and being directed to talk to the "DBA", otherwise known as the controller's executive assistant who did most of the "administering" of the DB. You know - adding/removing/editing records, administrative kind of stuff.

    Funny thing - when I used to do that role - it was called "data entry".....

    Your mileage may vary...widely. It's not at all shocking to me that you might have a DBA being the guy who was swapping the tapes at night....

    ----------------------------------------------------------------------------------
    Your lack of planning does not constitute an emergency on my part...unless you're my manager...or a director and above...or a really loud-spoken end-user..All right - what was my emergency again?

  • That's pretty much true, Matt... I'm amazed at what people think a DBA is supposed to do... no wonder it's so hard to find that type of job in Michigan without also knowing Java and C# 😉

    --Jeff Moden


    RBAR is pronounced "ree-bar" and is a "Modenism" for Row-By-Agonizing-Row.
    First step towards the paradigm shift of writing Set Based code:
    ________Stop thinking about what you want to do to a ROW... think, instead, of what you want to do to a COLUMN.

    Change is inevitable... Change for the better is not.


    Helpful Links:
    How to post code problems
    How to Post Performance Problems
    Create a Tally Function (fnTally)

  • Nowadays interviewers are looking for DBA who can do everything such as:

    sql server 2k, 2k5, replication (3 types), backups (3 types), disaster recovery, cluster server, SSIS, SSAS, SSIS, DTS, data model (erwin, power designer, etc), batch coding, performance tuning, data warehouse, Oracle, Sybase, Access, etc, etc, etc and on top of this HAVE excellent writing and communication skills.... How do you expect anyone to know all these things?

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