Oracle 12c new features for dba
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If database upgraded without proper testing of every expectations and requirements then some applications stuck. This feature allows us to add a new column with a default value within milliseconds instead of waiting for a long time and without generating lots of redo and undo which may impact the entire database. In 12c, you can have multiple indexes on the same column or set of columns as long as the index type is different.
A prime cause of this is the terrible practice of storing dates as strings. Better plan create test database server and execute all application with proper data load.
And your data is contained in an extensive set of application schemas. The Invisible columns is a very simple and straight-forward feature which can be useful if you would like to add a new column to a table but at the first stage you don't want that the application will be affected by the new column. Disaster recovery attributes like table level recovery, data file restoration through network are using very rarely because those features are only being used during recovery incident. Among these features there will be some which get the mainstream attention. And create a job to update it. The constraint name is just a tiny bit too long :. The parameter can be set at the database or session levels. From my point of view I think this feature can be useful although its biggest disadvantage is that it requires downtime to enable it which can be problematic for many Oracle customers. The in-memory columnar format does not replace the on-disk or buffer cache format, but is an additional, transaction-consistent copy of the object. If you don't want this, clone the element when you get it.
ilOUG meetup: Oracle 12c New Features For Better Performance (slides) - And you don't want one client to other's data.
Advanced Index Compression improves the compression ratios significantly while still providing efficient access to the index. Processing of large volumes of data is significantly faster than the exact aggregation, especially for data sets with a large number of distinct values, with negligible deviation from the exact result. The need to count distinct values is a common operation in today's data analysis. Optimizing the processing time and resource consumption by orders of magnitude while providing almost exact oracle 12c new features for dba speeds up any existing processing and enables new levels of analytical insight. This directive applies to any kind of direct path operation, such as a bulk insert or a move operation. Storing data that logically belongs together in close physical proximity can greatly reduce the amount of data to be processed and can lead to better compression ratios. This feature implements a new cache called big table cache for table scan workload. This big table cache provides significant performance improvements for full table scans on tables that do not fit entirely into the buffer cache. It should be used when the oracle 12c new features for dba cache size of the database instance is greater than the whole database size. More specifically, this feature improves the performance of full table scans by forcing all tables to be cached. This is a change from the default behavior in which larger tables are not kept in the buffer cache for full table scans. Greater improvements are seen in queries that include more dimensions and aggregate more rows from the fact table. In-Memory Aggregation eliminates the need for summary tables in most cases, thus simplifying maintenance of the star schema and allowing access to real-time data. The columnar format enables scans, joins and aggregates to perform much faster than the traditional on-disk formats for analytical style queries. The in-memory columnar format does not replace the on-disk or buffer cache format, but is an additional, transaction-consistent copy of the object. Because the column store has been seamlessly integrated into the database, applications can use this feature transparently without any changes. The optimizer is aware of In-Memory Column Store, so whenever a query accesses objects that reside in the column store and would benefit from its columnar format, they are sent there directly. The improved performance also allows more ad-hoc analytic queries to be run directly on the real-time transaction data without impacting the existing workload. The last few years have witnessed a surge in the concept of in-memory database objects to achieve improved query response times. In-Memory Column Store allows seamless integration of in-memory objects into an existing environment without having to change any application code. By allocating memory to In-Memory Column Store, you can instantly improve the performance of their existing analytic workload and enable interactive ad-hoc data extrapolation. If a file system directory is specified as the default location, then the directory must already exist; Oracle does not create it. The directory must have appropriate permissions that allow Oracle to create files in it. Oracle generates unique names for the files. A file created in this manner is an Oracle-managed file. This feature helps administrators to plug or to unplug databases from one container to another in a shared storage environment. The dictionary data in the source is copied as is but all user-created table and index data from the source is discarded. This feature enhances cloning functionality and facilitates rapid provisioning of development environments. This feature further improves rapid provisioning of pluggable databases. Administrators can spend less time on provisioning and focus more on other innovative operations. The source of the clone must remain read-only while the target needs to be on a file system that supports sparseness. Snapshot cloning support is now extended to other third party vendor systems. This feature eases the requirement of specific file systems for snapshot clones of pluggable databases. With file system agnostic snapshot clones, pluggable databases can be provisioned even faster than before. This feature enhances granular control and effectively reduces downtime of an application in planned or unplanned outages. This powerful clause helps convert cumbersome schema-based consolidations to more agile and efficient pluggable databases. Provisioning time for Oracle Database is significantly improved through centralized management while the updating of homes is simplified to linkage. Oracle snapshot technology is used internally to further improve the sharing of homes across clusters and to reduce storage space.
