3+Years Oracle DBA Interview Questions In response for a reader of this blog who asked me for some interview questions for a 3+Year experienced DBA I have written this series of questions that !ou can use in !our interviews" #ither if !ou are the interviewer or the interviewer" #n$o!% &" Basic '#ver! DBA should answer correctl! A(( these questions" )his knowledge is $ust basic for a 3+ !ear experienced DBA* &"& , -hich are the default passwords p asswords of .Y.)#/0.Y.1 A, /A2A#4 0 56A2#7827I2.)A(( &"9 , 6ow can !ou execute a script file in .(:(;.1 A, )o execute a script file in .(:lus t!pe < and then the file name" &"3 , -here can !ou find official 8racle documentation1 A, tahiti"oracle"com &"= , -hat is the address of the 8fficial 8racle .upport1 A, metalink"oracle"com or support"oracle"com &"> , -hat file will !ou use to establish 8racle connections from a remote client1 A, tnsnames"ora &"? , 6ow can !ou check if the database is accepting connections1 A, lsnrctl status or lsnrctl services &"@ , -hich log would !ou check if a database has a problem1 A, Alert log &" , 2ame three clients to connect conn ect with 8racle for example .( Developer A, .( Developer .(,:lus )8AD dbvisualiCer :(0.( Developer )here are several but an experienced dba should know at least three clients" &"E , 6ow can !ou check the structure of a table from sqlplus1 A, D#.54IB# or D#.5 &"&F , -hat command will !ou start to run the installation of 8racle software on (inux1 A, runInstaller 9" /oderate '.tandard knoledge for a dail!,work of ever! DBA" 6e could fail one or two questions but not more* 9"& , -hat should !ou do if !ou encounter an 84A,?FF1 A, 5ontact 8racle .upport 9"9 , #xplain the differences between :GI(# and .:GI(# A, A :GI(# is a .tatic text file that initialices the database parameter in the moment that itHs started" If !ou want to modif! parameters in :GI(# !ou !o u have to restart the database" A .:GI(# is a d!namic binar! file that allows !ou to overwrite parameters while the database is alread! started 'with some exceptions* 9"3 , In which 8racle version was Data :ump introduced1 A, 8racle &Fg 9"= , .a! two examples of o f D/( two of D5( and two of DD( A, D/( .#(#5) I2.#4) ;:DA)# D#(#)# /#4# 5A(( #:(AI2 :(A2 (85J )AB(# DD( 54#A)# A()#4 D48: )4;25A)# 58//#2) 4#2A/# D5( 4A2) 4#K8J#
9"> , You want to save the output of an 8racle script from sqlplus" 6ow would !ou do it1 A, spool script7name"txt select L from !our7oracle7operationsM spool offM 9"? , -hat is the most important requirement in order to use 4/A2 to make consistent hot backups1 A, Your database has to be in A456IK#(8 mode" 9"@ , 5an !ou connect to a local database without a listener1 A, Yes !ou can" 9" , In which view can !ou find information about ever! view and table of oracle dictionar!1 A, DI5) or DI5)I82A4Y 9"E , 6ow can !ou view all the users account in the database1 A, .#(#5) ;.#42A/# G48/ DBA7;.#4.M 9"&F , In linux how can we change which databases are started during a reboot1 A, #dit 0etc0oratab 3" Advanced 'A 3+ !ear experienced DBA should have enough knowledge to answer these questions" 6owever depending on the work he has done he could still fail up to = questions* 3"& , -hen a user process fails what 8racle background process will clean after it1 A, :/82 3"9 , 6ow can !ou reduce the space of )#/: datafile1 A, :rior to 8racle &&g !ou had to recreate the datafile" In 8racle &&g a new feature was introduced and !ou can shrink the )#/: tablespace" 3"3 , 6ow can !ou view all the current users connected in !our database in this moment1 A, .#(#5) 58;2)'L*;.#42A/# G48/ KN.#..I82 48;: BY ;.#42A/#M 3"= , #xplain the differences between .6;)D8-2 .6;)D8-2 284/A( .6;)D8-2 I//#DIA)# A2D .6;)D8-2 AB84) A, .6;)8-2 284/A( O .6;)D8-2 It waits for all sessions to end without allowing new connections" .6;)D8-2 I//#DIA)# 4ollback current transactions and terminates ever! session" .6;)D8-2 AB84) Aborts all the sessions leaving the database in an inconsistent state" ItHs the fastest method but can lead to database corruption" 3"> , Is it possible to backup !our database without the use of an 4/A2 database to store the catalog1 A, Yes but the catalog would be stored in the controlfile" 3"? , -hich are the main components of 8racle rid 5ontrol1 A, 8/4 '8racle /anagement 4epositor!* 8/. '8racle /anagement .erver* and 8/A '8racle /anagement Agent*" 3"@ , -hat command will !ou use to navigate through A./ files1 A, asmcmd 3" , -hat is the difference between a view and a materialiCed view1 A, A view is a select that is executed each time an user accesses to it" A materialiCed view stores the result of this quer! in memor! for faster access purposes" 3"E , -hich one is faster D#(#)# or )4;25A)#1 A, )4;25A)#
3"&F , Are passwords in oracle case sensitive1 A, 8nl! since 8racle &&g" =" 4A5 '8nl! intended for 4A5,specific DBAs with varied difficultied questions* ="& , -hat is the recommended method to make backups of a 4A5 environment1 A, 4/A2 to make backups of the database dd to backup !our voting disk and hard copies of the 854 file" ="9 , -hat command would !ou use to check the availabilit! of the 4A5 s!stem1 A, crs7stat ,t ,v ',t ,v are optional* ="3 , -hat is the minimum number of instances !ou need to have in order to create a 4A51 A, &" You can create a 4A5 with $ust one server" ="= , 2ame two specific 4A5 background processes A, 4A5 processes are (/82 (/Dx (/.n (J5x and DIA" ="> , 5an !ou have man! database versions in the same 4A51 A, Yes but 5lusterware version must be greater than the greater database version" ="? , -hat was 4A5 previous name before it was called 4A51 A, 8:. 8racle :arallel .erver ="@ , -hat 4A5 component is used for communication between instances1 A, :rivate Interconnect" =" , -hat is the difference between normal views and 4A5 views1 A, 4A5 views has the prefix PH" Gor example KN.#..I82 instead of KN.#..I82 ="E , -hich command will we use to manage 'stop start* 4A5 services in command,line mode1 A, srvctl ="&F , 6ow man! alert logs exist in a 4A5 environment1 A, 8ne for each instance" >" /aster 'A 3+ !ear experienced DBA would probabl! fail these questions the! are ver! specifid and speciall! difficult" Be glad if heHs able to answer some of them* >"& , 6ow can !ou difference a usual parameter and an undocumented parameter1 A, ;ndocumented parameters have the prefix P7H" Gor example 7allow7resetlogs7corruption >"9 , -hat is BB#D1 A, An undocumented 8racle tool used for foresnic purposes" .tans for Block Browser and #Ditor" >"3 , )he result of the logical comparison '2;(( O 2;((* will be And in the case of '2;(( %O 2;((* A, Galse in both cases" >"= , #xplain 8racle memor! structure )he 8racle 4DB/. creates and uses storage on the computer hard disk and in random access memor! '4A/*" )he portion in the computer s 4A/ is called memor! structure" 8racle has two memor! structures in the computer s 4A/" )he two structures are the :rogram lobal Area ':A* and the .!stem lobal Area '.A*" )he :A contains data and control information for a single user process" )he .A is the memor! segment that stores data that the user has retrieved from the database or data that the user wants to place into the database"
>"> , -ill 4/A2 take backups of read,onl! tablespaces1 A, 2o >"? , -ill a user be able to modif! a table with .#(#5) onl! privilege1 A, 6e wonHt be able to ;:DA)#0I2.#4) into that table but for some reason he will still be able to lock a certain table" >"@ , -hat 8racle tool will !ou use to transform datafiles into text files1 A, )rick question !ou canHt do that at least with an! 8racle tool" A ver! experienced DBA should perfectl! know this" >" , .(Q .#(#5) L G48/ /Y7.56#/A"/Y7)AB(#M .:9,F?@ 5olumn or attribute t!pe can not be displa!ed b! .(L:lus -h! IHm getting this error1 A, )he table has a B(8B column" >"E , -hat parameter will !ou use to force the starting of !our database with a corrupted resetlog1 A, 7A((8-74#.#)(8.75844;:)I82 >"&F , 2ame the seven t!pes of 8racle tables A, 6eap 8rganiCed )ables Index 8rganiCed )ables Index 5lustered )ables 6ash 5lustered )ables 2ested )ables lobal )emporar! )ables 8b$ect )ables" Posted by admin
