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Oracle Data Buffer - Quiz

Each question is worth one point. Select the best answer or answers for each question.
 
1. Which is the main drawback from using the V$ views to gather the data buffer hit ratio?
Please select the best answer.
  A. The V$ views do not actually contain any buffer data.
  B. The V$ views do not accurately compute a buffer hit ratio.
  C. The V$ views only hold accumulated values since instance startup time.
  D. The V$ views require the DBA to run the bstat-estat utility.

2. What is the main purpose of the db_file_multiblock_read_count parameter?
Please select the best answer.
  A. To speed up full table scans by directing Oracle to read-ahead
  B. To speed up index scans by directing Oracle to hash the row key value
  C. To reduce the burden on the data buffer cache
  D. To improve the memory management of the SGA

3. Which is true about the data buffer hit ratio? (Choose all that apply)
Please select all the correct answers.
  A. The hit ratio only applies when a data block is requested more than once by Oracle.
  B. The hit ratio is more important than SQL tuning for database performance.
  C. The hit ratio should never fall below 90 percent, else Oracle performance will suffer.
  D. The hit ratio is very dynamic, and can change dramatically every minute.