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Interview Questions!

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  • How many memory layers are in the shared pool?
  • How do you find out from the RMAN catalog if a particular archive log has been backed-up?
  • How can you tell how much space is left on a given file system and how much space each of the file system’s subdirectories take-up?
  • Define the SGA and how you would configure SGA for a mid-sized OLTP environment? What is involved in tuning the SGA?

     

  • What is the cache hit ratio, what impact does it have on performance of an Oracle database and what is involved in tuning it?
  • Other than making use of the statspack utility, what would you check when you are monitoring or running a health check on an Oracle 8i or 9i database ?
  • How do you tell what your machine name is and what is its IP address?
  • How would you go about verifying the network name that the local_listener is currently using?
  • You have 4 instances running on the same UNIX box. How can you determine which shared memory and semaphores are associated with which instance?
  • What view(s) do you use to associate a user’s SQLPLUS session with his o/s process?
  • What is the recommended interval at which to run statspack snapshots, and why?
  • What spfile/init.ora file parameter exists to force the CBO to make the execution path of a given statement use an index , even if the index scan may appear to be calculated as more costly?
  • Assuming today is Monday, how would you use the DBMS_JOB package to schedule the execution of a given procedure owned by SCOTT to start Wednesday at 9AM and to run subsequently every other day at 2AM.
  • How would you edit your CRONTAB to schedule the running of /test/test.sh to run every other day at 2PM?
  • What do the 9i dbms_standard.sql_txt() and dbms_standard.sql_text() procedures do?
  • In which dictionary table or view would you look to determine at which time a snapshot or MVIEW last successfully refreshed?
  • How would you best determine why your MVIEW couldn’t FAST REFRESH?
  • How does propagation differ between Advanced Replication and Snapshot Replication (read-only)?
  • Which dictionary view(s) would you first look at to understand or get a high-level idea of a given Advanced Replication environment?
  • How would you begin to troubleshoot an ORA-3113 error?
  • Which dictionary tables and/or views would you look at to diagnose a locking issue?
  • An automatic job running via DBMS_JOB has failed. Knowing only that “it’s failed’, how do you approach troubleshooting this issue?
  • How would you extract DDL of a table without using a GUI tool?
  • You’re getting high “busy buffer waits’ - how can you find what’s causing it?
  • What query tells you how much space a tablespace named “test’ is taking up, and how much space is remaining?
  • Database is hung. Old and new user connections alike hang on impact. What do you do? Your SYS SQLPLUS session IS able to connect.
  • Database crashes. Corruption is found scattered among the file system neither of your doing nor of Oracle ’s. What database recovery options are available? Database is in archive log mode.
  • Illustrate how to determine the amount of physical CPUs a Unix Box possesses (LINUX and/or Solaris).
  • How do you increase the OS limitation for open files (LINUX and/or Solaris)?
  • Provide an example of a shell script which logs into SQLPLUS as SYS, determines the current date, changes the date format to include minutes & seconds, issues a drop table command, displays the date again, and finally exits.
  • Explain how you would restore a database using RMAN to Point in Time?
  • How does Oracle guarantee data integrity of data changes?
  • Which environment variables are absolutely critical in order to run the OUI?
  • What SQL query from v$session can you run to show how many sessions are logged in as a particular user account?
  • Why does Oracle not permit the use of PCTUSED with indexes?
  • What would you use to improve performance on an insert statement that places millions of rows into that table ?
  • What would you do with an “in-doubt” distributed transaction ?
  • What are the commands you’d issue to show the explain plan for “select * from dual’?
  • In what script is “snap$” created? In what script is the “scott/tiger” schema created?
  • If you’re unsure in which script a sys or system-owned object is created, but you know it’s in a script from a specific directory, what UNIX command from that directory structure can you run to find your answer?
  • How would you configure your networking files to connect to a database by the name of DSS which resides in domain icallinc.com?
  • You create a private database link and upon connection, fails with: ORA-2085: connects to . What is the problem? How would you go about resolving this error?
  • I have my backup RMAN script called “backup_rman.sh”. I am on the target database . My catalog username/password is rman/rman. My catalog db is called rman. How would you run this shell script from the O/S such that it would run as a background process?
  • Explain the concept of the DUAL table .
  • What are the ways tablespaces can be managed and how do they differ?
  • From the database level, how can you tell under which time zone a database is operating?
  • What’s the benefit of “dbms_stats” over “analyze”?
  • Typically, where is the conventional directory structure chosen for Oracle binaries to reside?
  • You have found corruption in a tablespace that contains static tables that are part of a database that is in NOARCHIVE log mode. How would you restore the tablespace without losing new data in the other tablespaces?
  • How do you recover a datafile that has not been physically been backed up since its creation and has been deleted. Provide syntax example.
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