3 You see multiple fragments in the SYSTEM tablespace, what should you check first?
Ans: Ensure that users don’t have the SYSTEM tablespace as their TEMPORARY or DEFAULT tablespace assignment by checking the DBA_USERS view.
Mention the four possible ways (direct or indirect) to execute an SQL query against an Oracle database?
Ans: The below are the four possible ways to execute an SQL query against an Oracle database;
3 Describe the hit ratio as it pertains to the database buffers. What is the difference between instantaneous and cumulative hit ratio; which should be used for tuning?
Ans: Hit ratio is a measure of how many times the database was able to read a value from the buffers versus how many times it had to re-read a data value from the disks.
A value greater than 80-90% is good, less could indicate problems. If you take the ratio of existing parameters this will be a cumulative value since the database started. If you do a comparison between pairs of readings based on some arbitrary time span, this is the instantaneous ratio for that time span.
Generally speaking, an instantaneous reading gives more valuable data since it will tell you what your instance is doing for the time it was generated over.
1 How do you know what SQL is currently being used by the session?
Ans: by going v$sql and v$sql_area
2 How do you get the information about a specific session?
What are the roles and responsibilities of Oracle database administrators?
Ans: Below is the list of roles and responsibility of any Oracle database Administrator;
Which init parameter do you have to set to bypass parsing?
What do you know about the Oracle database?
Ans: Oracle data base is one of the multi-model database management tools; this tool is developed and marketed by Oracle corporations. The main purpose of using the Oracle database tool is to run any online transaction processing, data warehousing, and work well with mixed database workloads.
4 You see the following on a status report?
Ans: redo log space requests 23 redo log space wait time 0 Is this something to worry about? What if the redo log space wait time is high? How can you fix this? Since the wait time is zero, no. If wait time was high it might indicate a need for more or larger redo logs.
Who is responsible to update the indexes?
Ans: Oracle database software automatically maintains and uses the data indexes. When you make any changes to the table then oracle database software automatically reflects the changes to relevant indexes.
What Mainly Database Tuning contains?
Ans: Optimizer is a mechanism that will make the execution plan of an SQL statement