5 Simple (But Important) Things To Remember About Oracle Database 12c views ,parameters and packages
Oracle is doing every thing to jump into the cloud bandwagon. With 12C, Oracle is trying to address the problem of Multitenancy through this feature. There is a radical change and a major change in the core database architecture through the introduction of Container Databases also called CBD and Pluggable Databases (PDB). The memory and process is owned by the Container Database. The container holds the metadata where the PDBs hold the user data. You can create upto 253 PDBs including the seed PDB
Pluggable Database Views,Parameter,Packages
|CDB_xyz||All of the objects in the CDB across all PDBs|
|DBA_xyz||All of the objects in a container or PDB|
|CDB_pdbs||All PDBs within CDB|
|CDB_tablespaces||All tablespaces within CDB|
|CDB_users||All users within CDB (common and local)|
|V$PDBS||Displays information about PDBs associated with the current instance|
|V$CONTAINERS||Displays information about PDBs and the root associated with the current instance|
|PDB_PLUG_IN_VIOLATIONS||Displays information about PDB violations after compatibility check with CDB|
|RC_PDBS||Recovery catalog view about PDB backups|
|ENABLE_PLUGGABLE_DATABASE||Required to create a CDB at CDB instance startup
|PDB_FILE_NAME_CONVERT||Maps names of existing files to new file names when processing a CREATE PLUGGABLE DATABASE statement|
|CDB_COMPATIBLE||Enables you to get behavior similar to a non-CDB
|PDB_OS_CREDENTIAL||Enables another OS user than oracle to connect to PDBs
This is one of the top features in Oracle 12C. Data Redaction in simple terms means, masking of data. You can setup a Data Redaction policy, for example salary field in a Employee table can be masked. This is called redaction.
When you do a select * from employee, it will show that the Salary is masked.
The new data masking will use a package called DBMS_REDACT. It is the extension to the FGAC and VPD present in earlier versions.
|Privilege||1) EXEMPT REDACTION POLICY
2) EXEMPT DDL REDACTION POLICY
3) EXEMPT DML REDACTION POLICY
Heat Map and Automatic Data Optimization
ILM (Information Life Cycle) is to reduce the cost of storage, improve performance and access times for both current as well as archived data and retain data long enough so as to satisfy regulatory laws and statutes related to data preservation
Oracle 12c as a new feature called Heat Map which tracks and marks data even down to the row and block level as it goes through life cycle changes.
ADO or Automatic Data Optimization works with the Heat Map feature and allows us to create policies at the tablespace, object and even row level which specify conditions to dictate when data will be moved or compressed based on statistics related to the data usage.
Real-time data access statistics are collected in memory in the V$HEAT_MAP_SEGMENT view and then regularly flushed by DBMS_SCHEDULER_JOBS to tables on disk like HEAT_MAP_STAT$ which is presented to the DBA via views like DBA_HEAT_MAP_SEG_HISTOGRAM and DBA_HEAT_MAP_SEGMENT.
Heat Map is enabled at the instance level by setting the parameter HEAT_MAP to ON.
5) DBA_ILMPOLICIES, DBA_ILMDATAMOVEMENTPOLICIES
6) DBA_ILMTASKS, DBA_ILMEVALUATIONDETAILS
|Init ora parameter||HEAT_MAP|
– EXECUTE_ILM, STOP_ILM
– PREVIEW_ILM, ADD_TO_ILM, REMOVE_FROM_ILM
– DISABLE_ILM, ENABLE_ILM
– CLEAR_HEAT_MAP_ALL, CLEAR_HEAT_MAP_TABLE
– SET_HEAT_MAP_ALL, SET_HEAT_MAP_TABLE
Oracle Database In-Memory
Oracle Database In-Memory provides a unique dual-format architecture that enables tables to be simultaneously represented in memory using traditional row format and a new in-memory column format. The Oracle SQL Optimizer automatically routes analytic queries to the column format and OLTP queries to the row format, transparently delivering best-of-both-worlds performance. Oracle Database 12c automatically maintains full transactional consistency between the row and the column formats, just as it maintains consistency between tables and indexes today. The new column format is a pure in-memory format and is not persistent on disk, so there are no additional storage costs or storage synchronization issues.
|New columns||1) INMEMORY_PRIORITY, INMEMORY_DISTRIBUTE, INMEMORY_COMPRESSION in DBA_TABLES, DBA_TAB_PARTITIONS
2) DEF_INMEMORY_PRIORITY, DEF_INMEMORY_DISTRIBUTE, DEF_INMEMORY_COMPRESSION in DBA_TABLESPACES
|Init ora parameter||INMEMORY_SIZE