Oracle Database Administration, Pl SQL, App DBA Discussions

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New Features in Oracle 12c

  1. Online renaming and relocation of datafile.

    SQL> alter database move datafile ‘location 1 (ASM/ NON-ASM)’ to ‘location 2 (ASM/ NON-ASM)’;

  • OVERWRITE

    SQL> alter database move datafile ‘location 1 (ASM/ NON-ASM)’ to ‘location 2 (ASM/ NON-ASM)’ REUSE;

     

  • KEEP

    SQL> alter database move datafile ‘location1(ASM/NON ASM)’ to ‘location2(ASM/NON ASM)’ KEEP;

  1. Putting multiple indexes on same column

Data Dictionary

Data Dictionary

Sys user owns the data dictionary.

Dictionary contains is data about data

They exist in datafiles of system tablespaces and sysaux tablespaces.

Data dictionary reference tables are read only so only SELECT sql is allowed. Even if we own these tables (sys user) we use views in order to rule of the possibilities of corrupting any data dictionary base table.

SQL> desc dict

Automatic Diagnostic Repository(ADR) and ADR Command Interpreter (ADRCI)

ADR - Automatic Diagnostic repository.

$ORACLE_BASE/diag/rdbms/dbname/sid/trace/

Multiple instances can use the same path which will be the central location for alert and trace information

 You just have to define its path in the INIT file

This is an xml file

The Records in the file is:

  • ORA errors (e.g., ORA-…)
  • DDL statements detals
  • Non default init parameters etc..

You can run sql command.

SELECT * FROM v$diag_info;

New Features in Oracle 12c

  1. Online renaming and relocation of datafile.

    SQL> alter database move datafile ‘location 1 (ASM/ NON-ASM)’ to ‘location 2 (ASM/ NON-ASM)’;

  • OVERWRITE

    SQL> alter database move datafile ‘location 1 (ASM/ NON-ASM)’ to ‘location 2 (ASM/ NON-ASM)’ REUSE;

     

  • KEEP

    SQL> alter database move datafile ‘location1(ASM/NON ASM)’ to ‘location2(ASM/NON ASM)’ KEEP;

  1. Putting multiple indexes on same column

Data Dictionary

Data Dictionary

Sys user owns the data dictionary.

Dictionary contains is data about data

They exist in datafiles of system tablespaces and sysaux tablespaces.

Data dictionary reference tables are read only so only SELECT sql is allowed. Even if we own these tables (sys user) we use views in order to rule of the possibilities of corrupting any data dictionary base table.

SQL> desc dict

Automatic Diagnostic Repository(ADR) and ADR Command Interpreter (ADRCI)

ADR - Automatic Diagnostic repository.

$ORACLE_BASE/diag/rdbms/dbname/sid/trace/

Multiple instances can use the same path which will be the central location for alert and trace information

 You just have to define its path in the INIT file

This is an xml file

The Records in the file is:

  • ORA errors (e.g., ORA-…)
  • DDL statements detals
  • Non default init parameters etc..

You can run sql command.

SELECT * FROM v$diag_info;

Password file in Oracle

Password file in Oracle is used by it to store password to authenticate users who have administrative privileges. In oracle until a user is not logged in he can’t connect to the databases so storing the passwords for these users in database is not logical.
For the users with administrative rights we have two methods available.:
(i) Using the password file
(ii) Through the operating system (using groups). Any user on the OS under dba group, can login as SYSDBA.

OEM (Oracle Enterprise Manager) Installation and configuration for Standalone Database, Oracle 12c , Linux 5.11 and 6.6

This article describes configuration of OEM (Oracle Enterprise Manager) on a Linux server for standalone database (one instance) Oracle 12c, where database is already created.

DBConsole is no more available for 12c. so for 12c when you run emca/ emctl command it says command not found.

The location for emctl in 12c is <Middleware_Home>/oms/bin

From this location the following command can be successfully run 

./emctl status oms

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Mon, 9/18/2017 - 11:56pm
Dewitt Jeffcott's picture
Dewitt Jeffcott answered the question ORA-00230: operation disallowed: snapshot control file enqueue unavailable with "When another process is backing up control file, error ORA-00230 occurs" in the Oracle and BTechies groups
Tue, 9/5/2017 - 9:52pm
Dewitt Jeffcott's picture
Dewitt Jeffcott answered the question ORA-19588: archived log RECID 17586 STAMP 851933878 is no longer valid with "You can use crosscheck command to handle this problem" in the Oracle and BTechies groups
Tue, 9/5/2017 - 9:36pm
Mon, 8/14/2017 - 1:21pm

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