Online Data Reorganization and Redefinition
The Online Data Reorganization & Redefinition feature in Oracle AI Database offers administrators unprecedented flexibility to modify table physical attributes and transform both data and table structure. Users retain full access to the database objects being modified.
Overview
As businesses become increasingly dependent on web and e-commerce applications, database availability is critical because application downtime can result in significant financial, operational, and reputational impact. Oracle AI Database helps organizations maintain database availability and manageability during table reorganization. Online table redefinition enables supported changes to table structures and physical attributes while allowing users to continue accessing the table during most of the operation.
Key Benefits
Reduce Planned Downtime
Keep tables available for read and write operations during most of the redefinition process, with a brief final transition.
Improve Data Organization
Reorganize table data and storage to potentially improve data block layout, query performance, response time, and disk space utilization.
Simplify Application Upgrades
Prepare and validate database changes while the existing table remains in use.
Increase Operational Flexibility
Control when to complete the redefinition and transition to the updated table.
Key Capabilities
- Online Table Changes - Modify supported table structures and physical attributes while the table remains available during most of the operation.
- Data and Storage Transformation - Apply supported changes to columns, partitions, tablespaces, compression, and other table properties.
- Continuous Synchronization - Synchronize changes made to the original table with the interim table while the redefinition is in progress.
- Dependent Object Management - Copy and manage supported indexes, triggers, constraints, privileges, and related objects.
- Change Validation - Validate and use data in the interim table before completing the redefinition.
- Optional Rollback Support - Retain the option to roll back the redefinition when rollback is enabled at the start of the operation.
How it Works
Online table redefinition creates an interim table with the desired structure and storage attributes. Oracle AI Database copies the existing data to the interim table and synchronizes changes made to the original table while the operation is in progress.
Administrators can periodically synchronize the interim table, validate its data, and manage supported dependent objects before completing the redefinition. The original table is locked briefly during the final completion step.
The table must be eligible for online redefinition, and the appropriate redefinition method depends on the table design. The process can use primary keys, pseudo-primary keys, or rowids to maintain synchronization.