AWR and ASH Analysis Methodology: A Structured Approach to Oracle Performance Diagnostics
Performance diagnostics without a methodology is archaeology — you dig until you find something interesting, not necessarily something important. Oracle’s AWR and ASH provide an extraordinarily detailed record of database activity, but interpreting them requires a structured approach. This article presents a top-down methodology that moves from macro to micro: DB Time → Wait Profile → Top SQL → Root Cause. The Foundation: DB Time DB Time is the total time all sessions spent working in the database (on CPU or waiting for database resources) during a snapshot period. It is the single most important number in the AWR report. ...