Following are the Performance Engineering Interview Questions Set #19. Q. 91 How does the “Top Timed Events” section help in identifying bottlenecks? Ans: It lists the wait events that consumed the most time during the snapshot period, allowing you to focus on the most significant performance inhibitors. Q. 92 What is the significance of the … Read more
In AWR, the ‘Instance CPU’ table comes under the ‘Report Summary’ section. Refer to the below figure: To analyse the ‘Instance CPU’ section, you must Look at the Host CPU and Instance CPU sections. The key things to look for are the values “%Idle” in the “Host CPU” section and “%Total CPU” in the “Instance … Read more
In AWR, the ‘Host CPU’ table comes under the ‘Report Summary’ section. Refer to the below figure: The following metrics are available in the ‘Host CPU’ table of an AWR report: CPUs The number of CPUs is the product of the number of cores and threads available on the database server. Formula: CPU = Number … Read more
In AWR, the ‘Wait Classes by Total Wait Time’ table comes under the ‘Report Summary’ section. Refer to the below figure: To analyse this section, firstly check for the ‘Wait Class’ column. If User I/O, System I/O and Others have moderate ‘Waits’ value then it is fine. But if ‘Concurrency’ under the wait class has … Read more
In AWR, the ‘Top 10 Foreground Events’ table comes under the ‘Report Summary’ section. Refer to the below figure: The following metrics are available in the ‘Top 10 Foreground Events’ table of an AWR report: DB CPU It shows the total wait time for DB CPU and waiting %. Referring to Figure 01, the total … Read more
What is Buffer Hit ratio OR Buffer Hit %? ‘Buffer Hit Ratio’ is measured by the percentage of times the data block is requested by the query and available in memory. It is also called the ‘Buffer-Cache Hit Ratio’. Effective use of the buffer cache can greatly reduce the I/O load on the database. If … Read more