ORACLE DBA INTERVIEW QUESTIONS (L3)

By -

  1. How good you are at performance tuning?
  2. A user has reported that they are facing slowness for a certain sql, what will be your approach to identify the issue?
  3. You see that plan hash value of a sql plan has changed and you have already a good plan available in AWR, how will you use that plan?
  4. What do you look in AWR report to identify the issue?
  5. As a DBA, when and how you reach out to conclusion that a certain issue could be related to network and not database.
  6. What is buffer busy wait event?
  7. What is log file sync wait event?
  8. What other wait event you have observed in your environment which was problematic, can you please describe the situation and remedy that you performed to resolve that issue?
  9. What is direct path read event in database, in what scenario this occurs?
  10. What is difference between logical and physical reads?
  11. What is DB file scattered read and parallel read?
  12. If you have to read 100G of data from database using one sql and it has to run 100 times, what method you will prefer, writing data into buffer and then read or what, what wait events you will see into database.
  13. What is fractured block?
  14. What is sql plan baseline?
  15. What is stale stats? and how does it impact the performance of the database.
  16. What information of stats are kept in data dictionary? how it impacts the performance?
  17. What is soft parse and hard parse?
  18. How you will check history of cpu load at os level?
  19. What is memory leak in database?
  20. How do you handle ORA-07445 error in database?
  21. What is a fail group? if in high redundancy only one fail group is there then what will be the impact? and if in Normal redundancy there is no fail group then what will be the impact?
  22. Do you know about oracheck report? what does it perform and what information it fetches?
  23. What is Partition pruning?
  24. If i want that for each and every new day a new partition should be created into database then which partitioning method should i use?
  25. If i have 100 records and i want to have 4 partitions and want equal amount of data to be distributed among each partition, which partitioning method should i use?
  26. Have you performed patching and upgrade on cluster?
  27. What are the pre-requisites you need to meet for grid upgrade?
  28. What errors you have faced during and post upgrades?
  29. How will you replace the ocr disk, and during replacement of ocr, what should be the status of crs?
  30. When you apply patches on grid binaries, that time what is the status of crs?
  31. If you have 5 or 6 dedicated oracle home for each instances running on a host on grid, how will you patch them in one go?



Comments

Post a Comment

Popular posts from this blog

How to set the root password after creating instance on oracle cloud

By -
How to set the root password after creating instance on oracle cloud? since you have created instance on oracle cloud, it requires you private .ppk key file to login from putty you can login on your instance by directly providing that private key. and on Linux/Unix defult user is "opc". since during creation of instance it  will not ask you for  root password. You dont need any password to connect to root. to connect to root type below command as opc user. [opc@sts ~]$ sudo su [root@sts opc]# by this you will login as root. Now change your password [root@sts opc]# passwd Changing password for user root. New password: Retype new password: passwd: all authentication tokens updated successfully. [root@sts opc]# All done. Thanks & Regards Nikhil Kumar.
Read more

TNS-12541 TNS-12560 TNS-00511 TNS:protocol adapter error No listener

By -
Oracle Listener does not start with errors:  TNS-12541: TNS:no listener TNS-12560, TNS-00511, Linux Error: 2: No such file or directory, The listener supports no services euls25002.sgp.st.com:oraSID 51> ps -ef | grep -i tns root       330     2  0 Jul19 ?        00:00:00 [netns] oraSID   17512     1  0 Jul20 ?        00:01:25 /oracleSID/SID/121/bin/tnslsnr LISTENER_SID -inherit oraSID   56223 56131  0 08:02 pts/1    00:00:00 grep --color=auto -i tns euls25002.sgp.st.com:oraSID 52> lsnrctl status LISTENER_SID LSNRCTL for Linux: Version 12.1.0.2.0 - Production on 25-SEP-2017 08:02:19 Copyright (c) 1991, 2014, Oracle.  All rights reserved. Connecting to (ADDRESS=(PROTOCOL=IPC)(KEY=SID.WORLD)) TNS-12541: TNS:no listener  TNS-12560: TNS:protocol adapter error   TNS-00511: No listener    Linux Error: 2: No such file or directory ...
Read more

Queryable inventory could not determine the current opatch status.

By -
[oracle@Testing02 OPatch]$ ./datapatch -verbose SQL Patching tool version 12.2.0.1.0 Production on Fri May 15 15:54:19 2020 Copyright (c) 2012, 2019, Oracle.  All rights reserved. Log file for this invocation: /testing/app/oracle/cfgtoollogs/sqlpatch/sqlpatch_29313_2020_05_15_15_54_19/sqlpatch_invocation.log Connecting to database...OK Bootstrapping registry and package to current versions...done Queryable inventory could not determine the current opatch status. Execute 'select dbms_sqlpatch.verify_queryable_inventory from dual' and/or check the invocation log /testing/app/oracle/cfgtoollogs/sqlpatch/sqlpatch_29313_2020_05_15_15_54_19/sqlpatch_invocation.log for the complete error. Prereq check failed, exiting without installing any patches. Please refer to MOS Note 1609718.1 and/or the invocation log /testing/app/oracle/cfgtoollogs/sqlpatch/sqlpatch_29313_2020_05_15_15_54_19/sqlpatch_invocation.log for information on how to resolve the above errors. SQL...
Read more