AWR – Instance Efficiency Percentages

AWR Instance Efficiency Percentages

In AWR, the ‘Instance Efficiency Percentages’ table comes under the ‘Report Summary’ section. Refer to the below figure: The following metrics are available in the ‘Instance Efficiency Percentages’ table of an AWR report: Buffer Nowait % (Buffer Nowait Ratio) This metric provides the percentage of availability of the data buffers. This ratio gives an idea … Read more

AWR – Load Profile

In AWR, the Load Profile table comes under the ‘Report Summary’ section. Refer to the below figure: The following metrics are available in the Load Profile table of an AWR report: DB Time(s) DB Time(s) is the number of average active sessions during the given period. The active sessions are calculated by dividing the ‘DB … Read more

Performance Engineering Interview Questions #12

Performance Engineering Interview Question 12

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

Performance Engineering Interview Questions #11

Performance Engineering Interview Question 11

Following are the Performance Engineering Interview Questions Set #11. Q. 51 In the AWR report, where can you find information about PGA memory usage? Ans: The “Memory Statistics” section, specifically under “PGA Aggr Target Stats,” provides insights into PGA memory usage, including total PGA allocated and in-use statistics. Q. 52: What does a high ‘PGA … Read more

Performance Engineering Interview Questions #10

Performance Engineering Interview Question 10

Following are the Performance Engineering Interview Questions Set #10. Q. 46 What is a Large Pool in Oracle DB? Ans: The large pool is an optional memory area intended for memory allocations that are larger than is appropriate for the shared pool. It can provide large memory allocations for the following: Q. 47 What is Java Pool … Read more

Performance Engineering Interview Questions #9

Performance Engineering Interview Question 9

Following are the Performance Engineering Interview Questions Set #9. Q. 41 What is Library Cache in Oracle DB? Ans: The library cache is a shared pool memory structure that stores executable SQL and PL/SQL code. This cache contains the shared SQL and PL/SQL areas and control structures such as locks and library cache handles. The library cache … Read more