Hello friends, in this article we are going to discuss with you what is the difference between AWR (Automatic Workload Repository), ADDM (Automatic Database Diagnostic Monitor), and ASH (Active Session History). Through this short description, you will get a basic idea about all of them. AWR vs ADDM vs ASH?

Let’s understand about AWR vs ADDM vs ASH

AWR – Automatic Workload Repository

The Automatic Workload Repository is used to collecting performance statistics including:

  • Active Session History (ASH) statistics from the v$active_session_history view.
  • Wait events used to identify performance.
  • Time model statistics including the amount of DB time associated with the process from the v$sess_time_model and v$sys_time_mode views.
  • Object usage statistics.
  • Some system and session statistics from the v$sysstat and v$sesstat views.
  • Resource intensive SQL statements.

ADDM – Automatic Database Diagnostic Monitor

Analyzes data in the Automatic Workload Repository to identify potential performance bottlenecks and we use if for the following cases:

  • CPU bottlenecks
  • I/O capacity issues
  • Undersized Memory Structures
  • High load SQL statements
  • RAC specific issues
  • Database configuration issues
  • It also provides recommendations on Hardware Changes, Database Configuration & Schema changes.

ASH – Active Session History

Statistics from the in-memory performance monitoring tables also used to track session activity and simplify performance tuning.

ASH reports give the following information:

  • Top user events (frequent wait events)
  • Details to the wait events
  • Top sessions
  • Top queries
  • Top blocking sessions
  • Top DB objects
  • Activity over time

So friends in this article we learn about AWR vs ADDM vs ASH, hope you found this article very informative.

Read – Querying Tablespace Usage

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