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ASM : ASMCMD in 12c

New ASMCMD commands, now ASMCMD has the ability to do password file management, patches on asm instances, and version

pwcopy Copies a password file to the specified location. pwcreate Creates a password file at the specified location. pwdelete Deletes a password file at the specified location. pwget Returns the location of the password file. pwmove […]

Administration : How to distinguish you are seeing rows on CDB or PDB


In view of multiple databases sharing single SGA how to distinguish which database you will need to see.

Now all dynamic views has two new columns for example:- V$process


Administration : 12c Deprecated parameters

Here is the list of deprecated parameters as of

SQL> SELECT name from v$parameter WHERE isdeprecated = 'TRUE' ORDER BY name; active_instance_count background_dump_dest buffer_pool_keep buffer_pool_recycle commit_write cursor_space_for_time fast_start_io_target global_context_pool_size instance_groups lock_name_space log_archive_local_first log_archive_start max_enabled_roles parallel_automatic_tuning parallel_io_cap_enabled parallel_server parallel_server_instances plsql_v2_compatibility remote_os_authent resource_manager_cpu_allocation sec_case_sensitive_logon serial_reuse sql_trace standby_archive_dest user_dump_dest

Administration : Restrict PGA using PGA_AGGREGATE_LIMIT

Until 12c we cannot restrict the PGA memory, even though you set pga_aggregate_target its just a soft limit, sessions can go beyond that.

However, we can restrict PGA using PGA_AGGREGATE_TARGET parameter and limiting the memory access, This is extremely useful in consolidated databases running on a host, but again the baseline should be done before […]

Administration : Invisible Columns in 12c

Starting 12c you can make columns invisible as like you make indexes invisible.

The following actions can be applicable on invisible columns SELECT * FROM statements in SQL DESCRIBE commands in SQL*Plus %ROWTYPE attribute declarations in PL/SQL Describes in Oracle Call Interface (OCI)

Few Notes:-

When using select, when you dont select the […]

Administration : THREADED_EXECUTION new param and new model for BG processes

By default, some background processes on UNIX and Linux always use threaded execution; the remaining Oracle processes run as operating system processes. Thus, an “Oracle process” is not always equivalent to an “operating system process.”

Parameter THREADED_EXECUTION specifies whether to enable the multithreaded Oracle model. Starting in Oracle Database 12c, the multithreaded Oracle model enables […]

Administration : Undo stores in Temporary tablespace?

Yes for for Temporary Tables.

Here is the excerpt from the documentation:-

By default, undo records for temporary tables are stored in the undo tablespace and are logged in the redo, which is the same way undo is managed for persistent tables. However, you can use the TEMP_UNDO_ENABLED initialization parameter to separate undo for temporary […]

Administration : Hiding rows with ROW ARCHIVAL VISIBILITY

An direct example from documentation with clear explanation

In-Database Archiving enables you to archive rows within a table by marking them as inactive. These inactive rows are in the database and can be optimized using compression, but are not visible to an application. The data in these rows is available for compliance purposes if needed […]

Administration : Enable DDL Logging

In 12c you can enable DDL logging, before to that there was no way to know who has done the DDL on that object unless auditing enabled.

The ENABLE_DDL_LOGGING initiation parameter must be configured in order to turn on this feature.

The parameter can be set at the database or session levels.


Security : Privilege Capture – Helps to Audit

Privilege capture is a feature to track the privileges that is used for a user, This is very useful in auditing and show results of privileges has used during the capture period.

In 12c the Separate user duties are as below

SQL> select username from dba_users where username like '%SYS%'; USERNAME ———————————- SYS : Super […]