Oracle Performance Tuning Time Model statistics

The Time Model for oracle performance optimization collects statistics on the time model. The time model counts the time spent in the database according to the operation type. The most important time model is the database time-DB time, which represents the total time of the front-end session in the database, and is an indicator of the overall instance load .. Database time is an important proportion of the response time of all users. SESSION is a logical entity in the memory of the data instance, which indicates the status of the user currently logged on to the database. The database time can be calculated by the accumulated CPU time, and the active user (the session is not idle) wait time. For any database Request, the CPU time is the sum of the time spent by a work request. However, the wait time is the sum of the time spent waiting for various resources of the database instance. The DB time includes the processing time of the Knowledge client and does not include the processing time of the background process. For example, when the instance is started, the database time is accumulated. The database time should be used to compose all non-idle user sessions. The database time can exceed all the time since the instance was started. For example, if an instance has been started for five minutes but has four active sessions, the database time is 20 minutes. This is longer than the instance startup time. The goal of database optimization is to reduce the database time. In this sense, you can improve the response time of transactions for all users in the application.