Re: Oracle DBA Interview Questions
Date: Mon, 14 Mar 2016 18:05:49 +0000
Message-ID: <425BEFA1-5CA1-411C-B28E-3F1E68307577_at_businessolver.com>
Oh, don't misinterpret my DBCA comment. I think it's a great tool. My point was to have them do some operation that they lack familiarity with, requires a basic set of skills and some research. If they use create database all the time, maybe I'd have them use DBCA.
My comment should not be interpreted as anti-DBCA in any way. I use it all the time.
RF
Robert G. Freeman
DBA, Troublemaker, Malcontent
Businessolver
On Mar 14, 2016, at 12:55 PM, Chris Taylor <christopherdtaylor1994_at_gmail.com<mailto:christopherdtaylor1994_at_gmail.com>> wrote:
Interesting hang up you have on the DBCA. I'm an old-school DBA as well (having started with 7.2 - so probably not as old as you *wink* ) but I have to tell you. Using DBCA makes things a lot easier and lets me focus on doing other things with the time I save. (Of course I have some basic skeletons of create database scripts on my portable hard drive, but most likely a candidate is not going to have those scripts readily available).
The reason I mention the above, is we (all of us) need to quit turning our noses up at some of the tools available and instead take advantage of the tool that makes the most sense if time is important. As I get older, time is increasingly important I realize. And humbleness! :D
Chris
On Mon, Mar 14, 2016 at 11:31 AM, Robert Freeman <rfreeman_at_businessolver.com<mailto:rfreeman_at_businessolver.com>> wrote: Respectfully, I find the notion of DBA interview questions along these lines tedious, at best and not a realistic measure of a DBA’s value, worth or knowledge. Such questions open way to many psychological issues – stress, fear, pressures for many people. These kinds of questions that are not a good measure of a DBA’s ability to actually do the job. Sitting and answering questions under stress is nothing like recovering a database under pressure. At least, that’s true for me. I worked with Exadata for five years. Start asking me questions in this manner, I’m pretty sure I’d sound like I could barely spell Exadata let alone manage it. Yet – I assure you – if that thing craters – you probably want me fixing it. I know more than a few customers certainly did when that was my focus.
Who the devil is possibly going to remember every detail on a product where the documentation could easily reach the depths of the Marianas Trench? Then, with each question missed, factor in the “Oh blast, I just screwed up” count going up and the likelihood of finding the answer to the next question in the bright lights of an interview just go way down, and down and down. This is not how one measures the worth of the DBA, nor his/her experience – at least that’s my POV.
For consultants who’s every next assignment is nothing like the last assignment – so what if they spent the last 12 months working with encryption – if they have spent the next 6-months working with some other gnarly feature, the cobwebs of encryption are well beyond easy and instant recall. If you have photographic memory – my hats off to you – I don’t. I remember concepts, architecture and basic how-to’s… the details change so quickly, with each version in many cases, that there is little value to stuffing them in my head anyway.
What do I find the most effective way to gauge a DBA’s skill? I look at their resume, sit them at a computer and ask them to find me an answer to a problem that is relevant but that they have never faced (or they faced long ago and could not remember to save their life). Let me see their basic knowledge and research skills in action. Let me see how they are going to GET the relevant answers to a problem that they have never faced, under some due pressure. How intuitive are they at getting to the answer? That’s what I want to see. How creative are they, yet how structured are they? That’s what I find important.
Then – let’s have an open book practical exercise. Create a database for me – using an OS you are familiar with, and without using the DBCA. Have not done it in a while – great, here are is the documentation – here is a list of physical disks all ready to go and here are the tablespaces, sizes and related schemas – no GO! Give them a reasonable amount of time to complete the task and measure…
I think that the trough of interview is a legacy we can do without….
My opinion, of course…. I’ve been wrong before, I’ll be wrong again..
Robert
From: oracle-l-bounce_at_freelists.org<mailto:oracle-l-bounce_at_freelists.org> [mailto:oracle-l-bounce_at_freelists.org<mailto:oracle-l-bounce_at_freelists.org>] On Behalf Of Anton
Sent: Monday, March 14, 2016 4:54 AM
To: oracle-l_at_freelists.org<mailto:oracle-l_at_freelists.org>
Subject: Re: Oracle DBA Interview Questions
hello =) best question in my interview was: when selects without any funtions can do redo ? On 03/08/2016 02:56 PM, rob_at_oraclewizard.com<mailto:rob_at_oraclewizard.com> wrote: I've put togehter some questions for Oracle DBA's; however one of my co-workers say the questions are a bit tough. Said "we don't want to scare a potential employee." Can y'all comment, are these questions too hard? Should I include more Backup and Recovery? What are your thoughts? -Rob
- Make a column not null, but you have null values in the column. How would you approach the problem?
- How would you change the encryption algorithm on a tablespace.
- Can you rekey (rotate keys) for encrypted tablespaces?
- What process would you use to encrypt data in an existing tablespace?
- How to you rekey change the encryption algorithm on an encrypted column?
- Alter table <table name> rekey using ‘<encryption algorithm>’;
- A junior DBA deleted some archive logs prior to them being applied to the standby database. How do you get the standby database resynced?
- You have encrypted a set of columns, there are existing indexes on those columns. When you encrypted the columns, did the index get encrypted?
- You ran an datapump backup of encrypted data, you did not specify encryption in the datapump command line, is the datapump file encrypted?
- In rman, you have executed CONFIGURE ENCRYPTION FOR DATABASE ON; What encryption algorithm will Oracle use?
- select algoritm_name, is_default from V$RMAN_ENCRYPTION_ALGORITHMS;
- How do you find out what users still have the default password?
- dba_users_with_defpwd
Robert P. Lockard Oracle ACE
President Oraclewizard.com<http://Oraclewizard.com>, Inc.
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