December 15, 2011 at 8:29 am
Brandie Tarvin (12/15/2011)
Dev (12/15/2011)
there are at about 7 types of SQL Server DBAs in the world
Would you please share it here or give a pointer to the article.
Here's an old article from 2001 by Brian Knight on DBA Types[/url]. There only used to be three: Production, Development, and Hybrid. That's changed a lot.
This is my list:
Production DBA - only supports SQL Server in a production environment. Does little to no development and may have limited access to certain roles or needs due to corporate segregation of DBA duties.
DBA Developer - develops code solutions (procs, functions, views) to be tested and eventually moved up to production. Does not have access to production environments due to corporate segregation of DBA duties.
DBA Data Architect - Develops and designs databases in accordance to business unit needs.
Business Intelligence DBA - Supports SSAS, SSRS, and SSIS in various environments for the users. Develops BI solutions for the corporation.
Dev / BI hybrid DBA - Does both T-SQL and BI development but seldom supports the users directly.
Everything DBA - the person who works at a small enough office that (s)he is expected to do production support, development, data architecture, BI work, and even a little bit of regular Server Admin support. (This is me).
Accidental DBA - Opps. I'm a power user that knows a little bit about server administration and T-SQL. How the heck did I get to be the person expected to know all things SQL Server?
I'm sure there are more ways to slice this pie. This is Brad McGhee's list according to http://sqlpost.blogspot.com/2009/06/sql-server-dba-types-logical-dba-vs.html
•DBA System Administrator
•DBA Database Designer
•DBA Developer
•DBA High Availability Specialist
•DBA Business Intelligence Specialist
•DBA Report Writer
I don't know that I've ever had a job where I was just one of those. : -)
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December 15, 2011 at 9:13 am
How come nobody mentioned "Restart SQL Server service or Windows" in any posts? We are, after all, working with Microsoft... 🙂
"Have you tried turning it on and off again?" -IT Crowd
Jared
Jared
CE - Microsoft
December 15, 2011 at 9:18 am
SQLKnowItAll (12/15/2011)
How come nobody mentioned "Restart SQL Server service or Windows" in any posts? We are, after all, working with Microsoft... 🙂"Have you tried turning it on and off again?" -IT Crowd
Jared
:w00t:
December 15, 2011 at 9:39 am
SQLKnowItAll (12/15/2011)
..."Have you tried turning it on and off again?" -IT Crowd..
Darned, I loved that series.
You've just made my day even better. #Goodtimes
The IT crowd - Truest moment about tech support
Johan
Learn to play, play to learn !
Dont drive faster than your guardian angel can fly ...
but keeping both feet on the ground wont get you anywhere :w00t:
- How to post Performance Problems
- How to post data/code to get the best help[/url]
- How to prevent a sore throat after hours of presenting ppt
press F1 for solution, press shift+F1 for urgent solution 😀
Need a bit of Powershell? How about this
Who am I ? Sometimes this is me but most of the time this is me
December 15, 2011 at 12:11 pm
Dev (12/15/2011)
I don’t think there are organizations (even the giants) which employ BI DBAs or HA DBAs. If you are a PROD DBA, you are assumed to be HA DBA as well.
As a BI Developer, most of the time they assume I'm also a BI DBA.
Need an answer? No, you need a question
My blog at https://sqlkover.com.
MCSE Business Intelligence - Microsoft Data Platform MVP
December 15, 2011 at 12:13 pm
ALZDBA (12/15/2011)
SQLKnowItAll (12/15/2011)
..."Have you tried turning it on and off again?" -IT Crowd..Darned, I loved that series.
You've just made my day even better. #Goodtimes
I especially love the episode where he can't say "Have you tried turning it on and off again?" because of a bet.
Amateur hour!
Need an answer? No, you need a question
My blog at https://sqlkover.com.
MCSE Business Intelligence - Microsoft Data Platform MVP
December 17, 2011 at 7:17 am
Koen Verbeeck (12/15/2011)
Dev (12/15/2011)
I don’t think there are organizations (even the giants) which employ BI DBAs or HA DBAs. If you are a PROD DBA, you are assumed to be HA DBA as well.As a BI Developer, most of the time they assume I'm also a BI DBA.
They underestimated you... You are Everything DBA 😛
December 17, 2011 at 12:13 pm
All the answers so far have been criticism or jokes. Nobody found it useful to know what they ask at real interviews???
Anyway, I am not currently looking for a job or going to interviews,but from his list I found 4 questions that I very much want to know the answer of experts here on the forum (not for interview but for my own knowledge and understanding of what answer you are looking for as the person hosting interview).
I am also not a native English speaker, but I tried to rewrite his questions in a little better English...
1. Is it possible to set isolation level manually for single query?
I think the answer may be something like "yes you can" because you can set isolation level for a transaction and since a single query is also a transaction,it's the same thing... but I am not 100% sure.
2. How often should you check and correct index fragmentation? What strategy of detecting fragmentation do you follow as a DBA?
3. You have a query that has been running once per day for a period of one year with no problems. This query collects data from the previous business day and usually takes five minutes to run. No changes have been made but suddenly today this query took 30 minutes to execute. What could cause this?
4. You’re the DBA. The phone rings. One of the users is on the line. This user is unable to connect to the database. The user has been with the company for a long time and was always able to connect before. How do you investigate what’s wrong?
December 17, 2011 at 1:25 pm
Oksana March (12/17/2011)
All the answers so far have been criticism or jokes. Nobody found it useful to know what they ask at real interviews???
For anything other than a joke interview, the interviewer will adjust questions based on what is in the CV and on previous answers. Memorising answers to questions is a good way to lose the job. It's not hard for an interviewer to tell, just one question digging into details of the persons answer, if they've memorised answers they are lost.
So yes, the answers have been criticisms or jokes because quite frankly if someone is intent on faking their way into a job they cannot do, I am not going to help them do that. I've worked with a couple of people who did that, I will not willingly inflict that on anyone.
2. How often should you check and correct index fragmentation? What strategy of detecting fragmentation do you follow as a DBA?
Google for index fragmentation, index maintenance, also look in Books Online Index Management. There's lots written, more than I can write in a couple of lines.
3. You have a query that has been running once per day for a period of one year with no problems. This query collects data from the previous business day and usually takes five minutes to run. No changes have been made but suddenly today this query took 30 minutes to execute. What could cause this?
4. You’re the DBA. The phone rings. One of the users is on the line. This user is unable to connect to the database. The user has been with the company for a long time and was always able to connect before. How do you investigate what’s wrong?
There's no right or wrong answer to those questions (well, other than an answer that shows a complete lack of experience). They're digging into how you troubleshoot problems. Where do you start, what do you look for. I could tell you mine, it would be completely different to Ninja's or anyone one else in this thread and it would do no good in an interview as any follow-on questions will be unanswerable, since you don't have my background or experience.
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability
December 19, 2011 at 6:29 am
Oksana March (12/17/2011)
All the answers so far have been criticism or jokes. Nobody found it useful to know what they ask at real interviews???Anyway, I am not currently looking for a job or going to interviews,but from his list I found 4 questions that I very much want to know the answer of experts here on the forum (not for interview but for my own knowledge and understanding of what answer you are looking for as the person hosting interview).
I am also not a native English speaker, but I tried to rewrite his questions in a little better English...
1. Is it possible to set isolation level manually for single query?
I think the answer may be something like "yes you can" because you can set isolation level for a transaction and since a single query is also a transaction,it's the same thing... but I am not 100% sure.
2. How often should you check and correct index fragmentation? What strategy of detecting fragmentation do you follow as a DBA?
3. You have a query that has been running once per day for a period of one year with no problems. This query collects data from the previous business day and usually takes five minutes to run. No changes have been made but suddenly today this query took 30 minutes to execute. What could cause this?
4. You’re the DBA. The phone rings. One of the users is on the line. This user is unable to connect to the database. The user has been with the company for a long time and was always able to connect before. How do you investigate what’s wrong?
I'm going to largely just "ditto" Gail (GilaMonster) on this, but thought I'd add my 1/2-cent worth.
1. Simply put, yes. But if that's all you know, hope and pray the interviewer doesn't follow this up with "How?", or, even worse, "Good. What are some of the isolation levels and how would you use them correctly?" The most important thing to know about isolation levels is why "NoLock" and "Read Uncommitted" can be really, really bad for your data, and what the default behavior is for SQL Server without those. After that, I'd say the next thing to learn is the various snapshot isolation flavors and the pros and cons of those. So, the simple answer of the question, as posted, isn't enough. You have to know "why", not just "what" on this kind of thing.
2. The only correct answer on this one is "it depends". The strategy I follow is dependent on the business needs and the data usage patterns. In some tables, no defragmentation is needed (or possible, for that matter). Learn why, and you'll find out a lot of useful information about the internals of how SQL Server works. In other tables, no fragmentation will occur. Learn how fragmentation happens in the first place, and then think of some examples that might make it not happen at all. In a few tables, fragmentation happens, could be fixed, but doesn't matter. Again, you'll need to know how that could be and why, and it's important to know if you plan on performance tuning databases. And then, of course, there are the tables where fragmentation happens, matters, and can be fixed. But frequency, et al, of fixing those depends on the uses of the tables and indexes.
3. Here, the interviewer is looking for what you would do. It's not so much about being technically correct as it is about determining how you personally go about solving problems. On this particular thing, my first suspicion would be a tipping point regarding data volume/stats, or a server reboot/service restart (do you know why that would cause a query to run more slowly than it has before?). There are plenty of other possibilities, but that's where I'd start.
4. Same thing. The interviewer wants to know how you'd go about solving the issue. It's more about querying your thought process than about a technically correct answer. Honestly, my first thought on any support call is still "is it plugged in and turned on?" because of too much help-desk type work in the late 80s. It's a habit for me, so that's probably where I'd start. Obvious things to check are the online state of the database, and whether it is accepting connections at all or not, the state of the login being used (possibly requiring calling whomever in IT is responsible for your Active Directory administration), and so on from there.
But, most importantly, the key thing for a successful interview and a satisfactory job experience, is don't just list out interview questions and hope for rote answers to them. It's a habit from the classroom, treating an interview like a test/exam, and it's a really bad habit that needs to be broken as quickly as a person can.
- Gus "GSquared", RSVP, OODA, MAP, NMVP, FAQ, SAT, SQL, DNA, RNA, UOI, IOU, AM, PM, AD, BC, BCE, USA, UN, CF, ROFL, LOL, ETC
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