Hiring (or being hired as) An Oracle DBA

Presentation 66

Hiring (or being hired as) An Oracle DBA

Presentation 66Michael R. AultMichael R. Ault

DMR-Trecom

IntroductionIntroduction

The DBA market is being saturated with The DBA market is being saturated with both jobs and candidates -- How do you both jobs and candidates -- How do you match one to the other?match one to the other?

The interview process is critical to hiring, or The interview process is critical to hiring, or being hired as a DBAbeing hired as a DBA

As a Senior Consultant for DMR-Trecom I As a Senior Consultant for DMR-Trecom I have had to develop an interview strategy to have had to develop an interview strategy to separate the “wheat from the chaff”separate the “wheat from the chaff”

Topics of DiscussionTopics of Discussion

What is a DBA?What is a DBA? What levels are there in the DBA job and What levels are there in the DBA job and

what are their qualifications?what are their qualifications? Interview ToolsInterview Tools Does certification mean anything?Does certification mean anything?

What Is A DBA?According to the DBA manual duties include:What Is A DBA?According to the DBA manual duties include:

Installing and upgrading the ORACLE Installing and upgrading the ORACLE Server and application tools.Server and application tools.

Allocating system storage and planning Allocating system storage and planning future storage requirements for the future storage requirements for the database.database.

Creating primary database storage Creating primary database storage structures (tablespaces) once developers structures (tablespaces) once developers have designed an application.have designed an application.

What is a DBA? (cont.)What is a DBA? (cont.)

Creating primary database objects (tables, Creating primary database objects (tables, views, indexes) once application developers views, indexes) once application developers have designed an application.have designed an application.

Modifying the database structure, as Modifying the database structure, as necessary, from information given by necessary, from information given by application developers.application developers.

Enrolling users and maintaining system Enrolling users and maintaining system security.security.

What is a DBA (cont.)What is a DBA (cont.)

Ensuring compliance with Oracle License Ensuring compliance with Oracle License agreements.agreements.

Controlling and monitoring user access to Controlling and monitoring user access to the database.the database.

Monitoring and optimizing the performance Monitoring and optimizing the performance of the database.of the database.

Planning for backup and recovery of Planning for backup and recovery of database information.database information.

What is a DBA (cont.)What is a DBA (cont.)

Maintaining archived data on appropriate Maintaining archived data on appropriate storage devices.storage devices.

Backing and restoring the database.Backing and restoring the database. Contacting Oracle Corporation for technical Contacting Oracle Corporation for technical

supportsupport Plus many other duties....Plus many other duties....

Distilled Version:To be a “Full Charge” DBA you must know:Distilled Version:To be a “Full Charge” DBA you must know:

InstallationInstallation Configuration managementConfiguration management SecuritySecurity Monitoring and TuningMonitoring and Tuning Backup and RecoveryBackup and Recovery Trouble ShootingTrouble Shooting Vendor InterfaceVendor Interface

Personality Traits of a Good DBAA good DBA exhibits:Personality Traits of a Good DBAA good DBA exhibits: Self ConfidenceSelf Confidence CuriosityCuriosity TenacityTenacity TactfulTactful Self starterSelf starter Detail orientedDetail oriented

Trait One: Self ConfidenceWithout it:Trait One: Self ConfidenceWithout it: They will constantly ask about decisions They will constantly ask about decisions

both major and minor.both major and minor. They will be afraid to show initiative.They will be afraid to show initiative. Will be afraid to admit they don’t know Will be afraid to admit they don’t know

something -- it isn’t bad not to know something -- it isn’t bad not to know something as long as you know where to something as long as you know where to look it up!look it up!

Trait Two: CuriosityWhy do you need it?Trait Two: CuriosityWhy do you need it? Oracle is constantly changing, and not all of Oracle is constantly changing, and not all of

the changes are documentedthe changes are documented You can’t depend on employer to provide You can’t depend on employer to provide

references, you must have them yourself.references, you must have them yourself. The Oracle toolset requires “Mining” to get The Oracle toolset requires “Mining” to get

the full benefit from the data dictionary, the full benefit from the data dictionary, DBMS_ packages and utility scripts.DBMS_ packages and utility scripts.

Trait Three: TenacityTrait Three: Tenacity

Trouble shooting requires tenacity (so does Trouble shooting requires tenacity (so does dealing with Oracle Support at times).dealing with Oracle Support at times).

Many times the “Next” solution is the Many times the “Next” solution is the correct one.correct one.

Tenacious DBAs solve their own problems Tenacious DBAs solve their own problems (usually proactively) but they know when to (usually proactively) but they know when to call for help.call for help.

Trait Four: Self StartingTrait Four: Self Starting

Important with any position, but especially Important with any position, but especially DBA.DBA.

DBA has to be proactive, not reactive.DBA has to be proactive, not reactive. DBA has to be willing to “Go where no one DBA has to be willing to “Go where no one

has gone before” and develop their own has gone before” and develop their own tools where none exist.tools where none exist.

Trait Five: TactfulTrait Five: Tactful

DBA deals with all levels of people from DBA deals with all levels of people from upper management to programmer to upper management to programmer to vendor.vendor.

Needs to be able to deflect unreasonable Needs to be able to deflect unreasonable demands without burning bridges.demands without burning bridges.

Has to be able to manage both upper Has to be able to manage both upper management’s and user’s expectations.management’s and user’s expectations.

Trait Six: Detail OrientedTrait Six: Detail Oriented

Dealing with Oracle requires detail oriented Dealing with Oracle requires detail oriented people, from command syntax to storage people, from command syntax to storage requirement specifications.requirement specifications.

DBA work requires documentation, of DBA work requires documentation, of tools, parameters and storage decisions.tools, parameters and storage decisions.

Most DBA work requires time management Most DBA work requires time management skills -- attending meetings like other skills -- attending meetings like other managers but also trench work.managers but also trench work.

Knowledge Required of DBAsTo reiterate:Knowledge Required of DBAsTo reiterate:

InstallationInstallation Configuration managementConfiguration management SecuritySecurity Monitoring and TuningMonitoring and Tuning Backup and RecoveryBackup and Recovery Trouble ShootingTrouble Shooting CommunicationCommunication

InstallationInstallation

Oracle is ported to many, many platforms. Oracle is ported to many, many platforms. Installation on OpenVMS is different than Installation on OpenVMS is different than on UNIX or NT.on UNIX or NT.

A bad install can ruin a production A bad install can ruin a production environment.environment.

DBA should be knowledgeable about your DBA should be knowledgeable about your platform.platform.

Configuration ManagementConfiguration Management

Database sizing - tablespaces, redo logs, Database sizing - tablespaces, redo logs, rollback segments, tables and indexes.rollback segments, tables and indexes.

Physical file placement (OFA)Physical file placement (OFA) RAID usage in your environment.RAID usage in your environment. RAW usage in UNIX and NT.RAW usage in UNIX and NT. Required kernel parameters for your Required kernel parameters for your

platform.platform.

SecuritySecurity

System and Object level securitySystem and Object level security Roles and ProfilesRoles and Profiles Secure Oracle (if required)Secure Oracle (if required) SQLNET security SQLNET security Password Security options (in ORACLE8)Password Security options (in ORACLE8)

Monitoring And TuningMonitoring And Tuning

Next to backup and recovery most Next to backup and recovery most important knowledge factor.important knowledge factor.

Detailed knowledge of the data dictionary is Detailed knowledge of the data dictionary is required.required.

Knowledge of the uses of TKPROF and Knowledge of the uses of TKPROF and EXPLAIN PLAN.EXPLAIN PLAN.

Knowledge of COST and RULE based Knowledge of COST and RULE based optimizers.optimizers.

Monitoring and Tuning (cont.)Monitoring and Tuning (cont.)

How indexes help or hurt you.How indexes help or hurt you. Use of Hints.Use of Hints. Initialization parameters and their uses.Initialization parameters and their uses. DBA_, ALL_, USER_ viewsDBA_, ALL_, USER_ views V$ dynamic performance tablesV$ dynamic performance tables SYS owned “$” tablesSYS owned “$” tables DBMS_ packages and UTL* scriptsDBMS_ packages and UTL* scripts

Backup and RecoveryBackup and Recovery

Most critical aspect of the DBA job.Most critical aspect of the DBA job. Must know import and export and sqlloaderMust know import and export and sqlloader Must understand hot and cold backups.Must understand hot and cold backups. Must understand partial recovery options.Must understand partial recovery options. Must understand archive logging.Must understand archive logging.

TroubleshootingTroubleshooting

Binary ability, either you have it or you Binary ability, either you have it or you don’t. (if you don’t, don’t be a DBA!)don’t. (if you don’t, don’t be a DBA!)

Requires an analytical approach tempered Requires an analytical approach tempered by leaps of faith (intuition).by leaps of faith (intuition).

Requires tenacity tempered with the Requires tenacity tempered with the willingness to ask for help.willingness to ask for help.

CommunicationCommunication

DBAs must be able to be understood.DBAs must be able to be understood. DBAs must be able to file intelligently DBAs must be able to file intelligently

written reports.written reports. DBA must be able to document actions, DBA must be able to document actions,

scripts and installations.scripts and installations.

Levels Of DBALevels Of DBA

Candidates will range from DBBS level to Candidates will range from DBBS level to full charge DBA level.full charge DBA level.

Resumes will not tell you this information, Resumes will not tell you this information, only a detailed in-depth interview can sort only a detailed in-depth interview can sort them out.them out.

How to Tell a DBBS(DataBase Baby Sitter)How to Tell a DBBS(DataBase Baby Sitter) Has a great looking resume.Has a great looking resume. Has managed lots of instances. Has managed lots of instances. Has no self-bought reference materials, may Has no self-bought reference materials, may

not even have a computer at home.not even have a computer at home. On most jobs they will have used third party On most jobs they will have used third party

monitoring tools.monitoring tools. Can’t answer questions about Data Can’t answer questions about Data

Dictionary or DBMS_ packages.Dictionary or DBMS_ packages.

How To Tell A DBAHow To Tell A DBA

Has a great looking resume.Has a great looking resume. Has managed lots of instances.Has managed lots of instances. Has bookshelf full of self bought referencesHas bookshelf full of self bought references Complains about the download time of the Complains about the download time of the

Oracle Demo packages from the web page Oracle Demo packages from the web page over his 56k modem line at home.over his 56k modem line at home.

Knows init.ora, Data dictionary and Knows init.ora, Data dictionary and DBMS_ packages and UTL* scripts cold.DBMS_ packages and UTL* scripts cold.

Converting a DBBS to DBAConverting a DBBS to DBA

Get then involved with IOUGGet then involved with IOUG Get them involved with CompuServe Get them involved with CompuServe

forums (ORAUSER, ORASUPP)forums (ORAUSER, ORASUPP) Get them their own paper copy of the docs.Get them their own paper copy of the docs. Train, train, trainTrain, train, train Other than for general monitoring, wean Other than for general monitoring, wean

them away from too many third party tools, them away from too many third party tools, until they no longer need them.until they no longer need them.

Developing Interview QuestionsDeveloping Interview Questions

Decide on categories neededDecide on categories needed Give specific questions with specific Give specific questions with specific

answers for detail questionsanswers for detail questions For questions with open ended answers, be For questions with open ended answers, be

sure the interviewer has the skill level to sure the interviewer has the skill level to understand the correct answer.understand the correct answer.

Assign point values to each question.Assign point values to each question. Handouts give examples.Handouts give examples.

Prequalification of CandidatesPrequalification of Candidates

Oracle Corp. Certification doesn’t count for Oracle Corp. Certification doesn’t count for much, if you attend the classes, you get much, if you attend the classes, you get certified (sorry Oracle) I’ve got 5 of them...certified (sorry Oracle) I’ve got 5 of them...

Third party training ranges from excellent Third party training ranges from excellent to very poor...to very poor...

The new test based certification, while not The new test based certification, while not perfect is a good starting point.perfect is a good starting point.

Always check references.Always check references.

AppearanceAppearance

Shows attention to detailShows attention to detail Shows social skill levelShows social skill level The days of the brilliant maverick are The days of the brilliant maverick are

numbered, besides, they are greatly over-numbered, besides, they are greatly over-rated.rated.

If they don’t care enough to dress properly If they don’t care enough to dress properly for your environment, do you want them in for your environment, do you want them in charge of your data?charge of your data?

SummarySummary

There is no magic formula.There is no magic formula. Hiring or being hired as a DBA is hard Hiring or being hired as a DBA is hard

work.work. Successful hiring or being hired as a DBA Successful hiring or being hired as a DBA

requires careful preparation.requires careful preparation.