Questions for a Jr. DBA

仔细的看了http://www.freelists.org/上的这篇帖子,非常受启发:

开始有人提出以下问题:

So, I am in the process of reviewing resumes from several JR and SSR

candidates for the team. The question I came up with is, what kind of

questions (technical) should I ask during the interview. I can’t use the

same questions I’d use with a Sr. DBA.

The questions i’ve come up with so far are the following:

1. Difference between EXTENT and BLOCK

2. Difference between USER and ROLE. When would you use each?

3. Command to extend a Tablespace (tricky question? should it be datafile?)

4. Command to backup controlfiles (all you can think of)

5. Steps to switch archivelog on or off.

6. Minimum requirements in order to take a level 1 online backup (tricky

question?)

7. What are the minimum required files to be backed up in order to be able

to recreate the database from scratch in the event of complete media

failure?

I may come up with more, but that’s what I have so far…

thanks in advance

Alan.-

 

回答者中摘抄两个感悟最深的:

其一:

believe the most useful interview strategy for DBAs, junior or senior, is to ask them to walk up the whiteboard and begin diagramming and explaining what the Oracle database is and how it works, and just keep going into detail where they feel comfortable until I ask them to stop.

Some people walk up, pick up a pen, and draw for 10 mins saying nothing. Others talk with their back to their interviewers. Others do a good job of explaining, using the whiteboard for emphasis, not as a crutch. Inevitably, something needs to be clarified or challenged or simply refuted, and it is very illuminating to see how the candidate deals with that.

I think this technique works for juniors, intermediates, and seniors. Pretty hard to hide knowledge or ignorance this way…

Along the way, the interviewer can ask questions like those below as well, if they wish. I think if it fits into context, it is less of an interrogation, and there is less emphasis on rote memorization? One thing is that I think candidates should be permitted the use of Google and online documentation, just as in real life, if they feel the need.

Hope this helps…

 

其二:

Every time I am asked to interview a junior dba I always start to

request what is expected from the candidate and the activities suppossed

to be covered. I have a small guide as a starting point and after that

getting deeper as much as possible depending on candidate and skills

requested:

1. Explain diff between instance and db (include as much details as

possible)

2. Mention all oracle objects you know (expect from user to mention,

materialized views, external tables, partitioned tables, etc)

3. Explain types of shutdowns and startup process. (include as much

details as possible)

4. What do you do when users say:

a) my session is not responding

b) my query is very slow

c) entire db reponse time is very slow

5. Differences among sp, packages, functions, triggers, anonymous blocks

6. What is an inner view? (tricky question, since you are talking about

oracle objects)

7. How to kill a session, unix and windows

8. Differences between users and schemas

9. What is OFA

10. How do you do your everyday activities/work? OEM, command line,

third party tools

After those basic question, you can change to an upper level:

What is the process that writes data from files to data buffer?

Describe advantages of LMT againts DMT

Where is the SCN (system change number)?

How to pin an object and what is the reason to do this?

How to rename a database

What is a deadlock and how can be solved?

What is a crash recovery and when happens?

Diff between a hotbackup and a cold backup

What is a latch

What is the SGA and how is formed

What steps do you take when troubleshooting and oracle performance

issue?

and so on..

but, no matter candidate level, you need to ask:

What do you do when you don’t know how to solve a problem?

How do you deal with top management pressure when having critical

issues?

regards,

 

以我现在的水平,估计连个业余级DBA都算不上,但还是要说说我对初级DBA和高级DBA的看法:

我认为初级DBA就是基本概念都能说个大概,问你个什么名词,让你解释解释,都能说的大差不差,但是谈到概念之间的联系与这表层概念背后的东西,估计初级DBA就说不出来了。高级DBA与之的区别在于,他们基础极其扎实,概念融会贯通。

看在我还业余的份上,咱也表表态,现在接触工作才发现,要学习的东西还有太多——数据库、操作系统、网络、存储、开发……以前看书总是从头开始,现在也开始重点突击,定点清除了。有些知识点,虽然有点超出咱的水平,但是自习看看总是能看明白的。除了明白还不行,还要与别的知识点相结合,同时经常总结、分析、提炼,如果有一天,能把这个知识点给别人讲明白,那咱自个就真明白了。不多说,干活吧。

  1. @zhouyf
    经常被面试?
    我只期待下次面试前,能更充实自己的知识体系,不保证全能答上来,起码要有解决思路

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