Shulou(Shulou.com)06/01 Report--

Preface: AWR report is an important report to understand the operation of ORACLE, and the use of CPU is an important indicator of AWR report. This document interprets AWR report from the perspective of a single CPU.

2. Introduction of important parameters:

DB Time:Amount of elapsed time (in microseconds) spent performing Database user-level calls. This does not include the elapsed time spent on instance background processes such as PMON.

Description: the total time spent by all DB TIME= foreground session on database calls

? Note that it is the foreground process foreground sessions

? Including CPU time, IO Time, and a series of other non-idle wait times, don't forget cpu on queue time

Formula: DB TIME= DB CPU + Non-Idle Wait + Wait on CPU queue

(thinking about the definition of DB TIME, the session designated for citizens is the front desk.)

DB CPU:Amount of CPU time (in microseconds) spent on database user-level calls. This does not include the CPU time spent on instance background processes such as PMON.

Description: simply understood as the CPU consumed by the database at run time

Check the load of the database

Example 1:

The database has been running for 60 minutes, and the operating system has 16 CPU, with a total of DB TIME:60 × 160960 minutes.

CPU spent 233.57 minutes dealing with Oralce non-idle waits and operations, which means that CPU has 233.57pc100% = 24.3%

Example 2:

The database has been running for 60 minutes, and the operating system has 4 CPU for a total of DB TIME:60 × 880 minutes.

CPU spent 0.62 minutes on processing Oralce non-idle waits and operations, which means that CPU has 0.62 + 480%.

Summary: it is obvious that the database load can be seen initially from DB Time, Elapsed and CPUs.

4. Check the CPU load of the database

Example 1:

DB CPU (S) indicates the consumption of the database on DB CPU each time it is run, and the above DB CPU/DB Time=97.5% (because of the decimal point, this value will have an error)

For a detailed CPU, you need to check the% Busy CPU of Instance CPU, which is currently 99.2%.

Example 2:

According to the above calculation, we can know that the CPU load of this system is also very easy.

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