Addm
DB CAFE
- DBA { Oracle DBA 명령어 > DBA 초급 과정 > DBA 고급 과정 }
- 튜닝 { 오라클 튜닝 목록 }
- 모델링 { 데이터 모델링 가이드 }
Overview of the Automatic Database Diagnostic Monitor When problems occur with a system, it is important to perform accurate and timely diagnosis of the problem before making any changes to a system. Oftentimes, a database administrator (DBA) simply looks at the symptoms and immediately starts changing the system to fix those symptoms. However, an accurate diagnosis of the actual problem in the initial stage significantly increases the probability of success in resolving the problem.
With Oracle Database, the statistical data needed for accurate diagnosis of a problem is stored in the Automatic Workload Repository (AWR). The Automatic Database Diagnostic Monitor (ADDM):
Analyzes the AWR data on a regular basis Diagnoses the root causes of performance problems Provides recommendations for correcting any problems Identifies non-problem areas of the system Because AWR is a repository of historical performance data, ADDM can be used to analyze performance issues after the event, often saving time and resources in reproducing a problem. For information about the AWR, see "Overview of the Automatic Workload Repository".
In most cases, ADDM output should be the first place that a DBA looks when notified of a performance problem. ADDM provides the following benefits:
Automatic performance diagnostic report every hour by default Problem diagnosis based on decades of tuning expertise Time-based quantification of problem impacts and recommendation benefits Identification of root cause, not symptoms Recommendations for treating the root causes of problems Identification of non-problem areas of the system Minimal overhead to the system during the diagnostic process It is important to realize that tuning is an iterative process, and fixing one problem can cause the bottleneck to shift to another part of the system. Even with the benefit of ADDM analysis, it can take multiple tuning cycles to reach acceptable system performance. ADDM benefits apply beyond production systems; on development and test systems, ADDM can provide an early warning of performance issues.
This section contains the following topics:
ADDM Analysis Using ADDM with Oracle Real Application Clusters ADDM Analysis Results Reviewing ADDM Analysis Results: Example