Following are the Performance Engineering Interview Questions Set #17. Q. 81 Is a high buffer cache hit ratio always indicative of good performance? Ans: Not necessarily. While a high hit ratio means most data requests are served from memory, it doesn’t account for inefficient queries or unnecessary data access patterns. It’s important to look at … Read more
Following are the Performance Engineering Interview Questions Set #16. Q. 76 Explain the “latch: cache buffers chains” wait event and its impact. Ans: This wait event indicates contention for cache buffer chain latches, which protect the hash chains of buffer headers in the buffer cache. High waits suggest hot blocks or heavy concurrent access to … Read more
Following are the Performance Engineering Interview Questions Set #15. Q. 71 How can you reduce the ‘Buffer Busy Waits’ identified in the AWR report? Ans: It can be reduced by: Q. 72 What are wait events in Oracle, and why are they important for performance analysis? Ans: Wait events represent the time sessions wait for … Read more
Following are the Performance Engineering Interview Questions Set #14. Q. 66 What is the difference between ‘db file sequential read’ and ‘db file scattered read’ wait events? Ans: The ‘db file sequential read’ indicates single-block reads, often associated with index lookups whereas ‘db file scattered read’ involves multi-block reads, typically from full table scans or … Read more
Following are the Performance Engineering Interview Questions Set #13. Q. 61 How can lock contention be identified in an AWR report? Ans: High wait events like “enq: TX- row lock contention” or “enq: TM- contention” indicate lock waits. The “Segments by Row Lock Waits” section shows which segments are involved. Q. 62 What does the … Read more
Following are the Performance Engineering Interview Questions Set #12. Q. 56 What role does the buffer cache play in database performance? Ans: The buffer cache stores copies of data blocks read from the disk. A properly sized buffer cache reduces physical I/O by satisfying requests from memory, thus improving performance. Q. 57 How can you … Read more