Questions and answers

What is the difference between an AWR report and an ADDM report?

What is the difference between an AWR report and an ADDM report?

The data in the snapshot interval is analyzed by ADDM. ADDM compares the difference between snapshots. By default, AWR generates snapshots of performance data once every hour.

What is AWR and ADDM reports?

The Automatic Database Diagnostic Monitor (ADDM) analyzes data in the Automatic Workload Repository (AWR) to identify potential performance bottlenecks. For each of the identified issues it locates the root cause and provides recommendations for correcting the problem.

What is AWR ADDM ash?

ADDM : automatic database diagnostic monitor analyzes data in the Automatic Workload Repository (AWR) to identify potential performance bottlenecks. and we use it for the following cases : CPU bottlenecks. Undersized memory structures. I/O capacity issues.

What is an ADDM report?

The Automatic Database Diagnostic Monitor (ADDM) is a self-diagnostic engine built into Oracle Database. ADDM examines and analyzes data captured in the Automatic Workload Repository (AWR) to determine possible performance problems in Oracle Database.

What is the use of AWR ADDM ash?

Performance Tuning for Oracle 10g/11g database ADDM uses data captured by AWR. e.g wait events, latches, locking, statistics and ASH data to identify the root causes of the problems. ADDM also provides recommendations and tells expected benefits.

How do I run an ash report?

Generating an ASH Report on the Local Database Instance

  1. At the SQL prompt, enter: @$ORACLE_HOME/rdbms/admin/ashrpt.sql.
  2. Specify whether you want an HTML or a text report: Enter value for report_type: text.
  3. Specify the begin time in minutes before the system date: Enter value for begin_time: -10.

What is the difference between ash and AWR?

Active Session History (ASH) : The Name of this reports describe what is the major difference between it and AWR , The ASH contains recent information on active sessions sampled every second. The AWR are taken every one hour and its one hour old will not help in diagnosing issues that are current on the database.

How do I generate an ash report?

What are the top 5 wait events in Oracle?

Oracle Wait Events and Solution

  • Buffer Busy Wait:
  • Db File Sequential Read :
  • Enq: TX – row lock contention :
  • Enq: TM – index contention :
  • Row Cache Lock Wait :
  • Read by Other Session :

What do ash reports look for?

ASH reports enable you to perform analysis of:

  • Transient performance problems that typically last for a few minutes.
  • Scoped or targeted performance analysis by various dimensions or their combinations, such as time, session, module, action, or SQL identifier.

What is CPU wait in Oracle?

“CPU Wait” time is Oracle foreground process OS CPU run queue time. I ran an experiment (detailed below) and as the OS CPU utilization increased, so did the DB Time “gap” implying that the gap is CPU run queue time or at least a significant part of it.

How do I find my ash report?

To run ASH reports: On the Performance page, under Average Active Sessions, click Run ASH Report. The Run ASH Report page appears. Enter the date and time for the start and end of the time period when the transient performance problem occurred.