You notice that all SQL statements that have a join condition on one particular table appear to be running very slowly. Which of these steps should you take first to help identify the performance problem?
A . Check to see if the database is running the CBO or RBO.
B. Verify that there are no missing indexes from the table.
C . Verify that the table blocks are stored in the buffer cache.
D . Check file I/O statistics for the data file and tablespace that the table is in.
Explanation:
Answer B: The problem statement clearly identifies at least one possible problem; that is the missing index on the columns in the join condition. If all queries were experiencing performance problems, then we might first verify that there are recent statistics on tables if the CBO is used. If objects in a specific tablespace were seen as performance constrained, we would check the file I/O statistics for the files in the tablespace.
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