Not long ago, weeding through DBA applicants with a tech interview was astraightforward process. You'd ask candidates 200 or so technical questions. If theygot 100 correct answers, you knew they'd been around the block; 150 or more andyou knew you were on to superior talent. But once the Oracle Certification Program(OCP) became popular in the late 90s, the traditional tech interview lost itseffectiveness. These days, candidates can answer 180 questions correctly and youstill won't know whether they're talking from experience or simply regurgitatingwhat they memorized at OCP a few weeks earlier. Although it has becomeincreasingly difficult to determine whether you've found a seasoned, highly qualifiedDBA or a newly minted OCP Graduate, there are ways.

First, start by throwing out the questions. Any candidate who has been through OCPknows the answers-all of them. That list that helped you find superstar employeesin the past is unfortunately useless now. Second, if you are a manager without soliddatabase experience, enlist the help of an experienced DBA to help you prepare thatcritical interview. IT Managers have varied backgrounds and here it's important topull from the right background, be it yours or someone else's.

You also need to analyze your needs. If you're looking to hire a junior person andmentor them, the OCP program ensures that the candidate has been exposed tomost areas of the Oracle RDBMS. You can assume you'll have an employee whoknows the commands and has a general concept of how a database works. But ifyou select an inexperienced OCP candidate thinking you're getting a skilled veteran,you'll be in for countless unpleasant surprises. Typical horror stories sound like: A DBA restores the backup for the first time in a real-life situation, finds out thebackup strategy was flawed and loses the whole database. S/he probably also forgotto make a backup of the database before attempting the recovery, thereforerendering Oracle support intervention nearly impossible.

A DBA recommends technical implementation decisions based on limited experiencewith a single user database that has 10 tables of 100 rows each. Of course, thesystem hangs a few hours after the launch-as soon as 10,000 users start poundingon a 500GB database.

The most damaging aspect of newer DBAs is that they don't know when they are inover their heads, or how to plan properly. Senior IT professionals, no matter theirfield of expertise, have a gut feeling when it's happening. They know they have tostep away, talk things over with a peer, roll everything back, and try another day.Inexperienced IT professionals are fearless and can therefore be dangerous,especially if they're expected to run the show.

So how do you find truly qualified DBAs in an OCP World? Put them to work-in theinterview, that is. Create real world situations where candidates are allowed full useof any familiar online resources, and see what they can do. Some examples:

Want to check out their data modeling skills? Give candidates a hypotheticalbusiness that everyone understands, like a video rental store, and a basic set ofbusiness requirements. Put them in front of a white board and let them create amodel that meets the stated requirements. You play the role of a subject-matterexpert who is decidedly non-technical, and have them walk you through the results.

Wondering how they handle troubleshooting? Set up a database with variousperformance anomalies such as poorly written queries, missing indexes, andinternal resource contention. Have applicants deal with the issues and walk youthrough their methodology. They can't use automated tools. The Oracle DataDictionary and OS basic facilities must suffice.

Want to see if they know how to minimize downtime? Pretend you're a client whowants to upgrade a 500GB database from version X to version X+1. It's a 24/7environment and each hour of downtime costs $10,000. There will be downtimeregardless, but the DBA should be able to generate scenarios to keep it at aminimum.

Whatever skills you're looking to assess, make sure you test candidates in situationsthey can't prepare for and can't fake. The new interview process isn't quite as easyas those trusty old 200 questions. It requires more up-front planning and oftenmore time in the interview room. But if it saves you from having to fire incapableemployees who wreaked havoc on your database, it's probably worth it. A littleadvance preparation can save a whole lot of time, money, and hassle down the road.And isn't that all we're looking for in this crazy, mixed-up OCP world?

Robert Hamel
DBA Team Lead
Rob has served as the applications architect for one of the largest governmentdatabases in the world, as well as a primary architect on a database with one of theworld's highest record of transactions per second. Before joining The Pythian Group in 2000, he worked for numerouscorporations and government agencies, including Human Resources andDevelopment Canada and Elections Canada. An acknowledged expert in the field,Rob excels in application architecture and application performance tuning.

Rob graduated from the University of Ottawa in 1987 and has been working withinformation systems ever since.