Oracle Automatic diagnostic Repository or ADR

The Automatic Diagnostics Repository (ADR) is a hierarchical file-based repository for handling diagnostic information.

ADRCI is a command-line tool that is part of the fault diagnosability infrastructure introduced in Oracle Database Release 11g. 

      ADRCI enables you to:

• View diagnostic data within the Automatic Diagnostic Repository (ADR).
• View Health Monitor reports.
• Package incident and problem information into a zip file for transmission to Oracle Support.

Diagnostic data includes incident and problem descriptions, trace files, dumps, health monitor reports, alert log entries, and more.

ADRCI has a rich command set, and can be used in interactive mode or within scripts. In addition, ADRCI can execute scripts of ADRCI commands in the same way that SQL*Plus executes scripts of SQL and PL/SQL commands.

ADR data is secured by operating system permissions on the ADR directories, hence there is no need to log in to ADRCI.

 ADR is automatically maintained by Oracle 11g to hold diagnostic information about critical error events. This repository is maintained in memory which enables database components to capture diagnostic data at its first failure for critical errors.

In Oracle 11g, the init.ora parameters like user_dump_dest and background_dump_dest are deprecated. They have been replaced by the single parameter DIAGNOSTIC_DEST which identifies the location of the ADR . ADR is file based repository for diagnostic data like trace file,process dump,data structure dump etc.

The default location of  DIAGNOSTIC_DEST  is  $ORACLE_HOME/log, and if ORACLE_BASE is set in environment  then DIAGNOSTIC_DEST is set to $ORACLE_BASE.  The ADR can be managed via the 11g Enterprise Manager GUI  (Database Control and not Grid Control) or via the ADR command line interpreter adrci.