Pluggable Database Relocation with Transparent Connection Forwarding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for cloning or moving pluggable databases between container databases require the source database to be in read-only mode, leading to significant downtime and increased costs due to the need for third-party tools and complex implementation processes, which restrict write operations and hinder efficient data refreshment.
Innovation Solution
A method to create a clone of a pluggable database while it remains in read-write mode, using database server instances to record timestamps, copy data files, and apply redo information for consistency, allowing for incremental refreshment and transparent connection forwarding during migration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the source pluggable database is placed in read-only mode for cloning or moving, then data consistency during the operation is ensured, but write operations are restricted and downtime increases
Solution Approach 1:
The system performs preliminary actions by recording timestamps and identifying data files before the cloning operation begins. This allows the system to prepare the necessary components for cloning while the source database remains in read-write mode, thus maintaining write operation availability while ensuring data consistency through pre-planned operations.
Solution Approach 2:
The patent introduces an intermediary mechanism using redo information and timestamps as mediators between the source database and the clone. This intermediary layer allows the cloning process to access and replicate data changes without requiring the source database to be in read-only mode, thus resolving the contradiction between data consistency and write operation availability.
2Ease of manufacture
If third-party tools are used for cloning pluggable databases, then cloning functionality is achieved, but implementation complexity and costs increase
Solution Approach 1:
The container database system performs cloning operations using its own built-in mechanisms and resources. The system utilizes its internal redo information, timestamps, and data file management capabilities to create clones without requiring external third-party tools. This self-service approach reduces implementation complexity and eliminates the need for additional software dependencies.
3Productivity
If the source pluggable database remains in read-write mode during cloning, then continuous write access is maintained, but ensuring data consistency becomes more difficult
Solution Approach 1:
The system implements feedback mechanisms by continuously recording timestamps and monitoring data file changes during the cloning process. This feedback allows the system to track and replicate all modifications made to the source database, ensuring that the clone remains consistent with the source even while the source continues to accept write operations.
Solution Approach 2:
The patent enables continuous useful action by allowing the source database to remain in read-write mode throughout the cloning operation. The cloning process continuously captures and replicates data changes without interruption, maintaining both write access availability and data consistency through ongoing synchronization rather than requiring periodic pauses.
4Reliability
If significant downtime is accepted during database relocation, then data consistency is ensured, but operational costs and service availability decrease
Solution Approach 1:
The system performs preliminary actions by preparing the clone and recording all necessary timestamps and data file information before the relocation begins. This preliminary preparation allows the actual data transfer and synchronization to occur efficiently with minimal interruption to service, thus reducing downtime while maintaining data consistency.
Solution Approach 2:
The patent maintains continuity of useful action throughout the relocation process by enabling the source database to remain accessible and functional. The cloning and relocation operations proceed in the background with continuous data synchronization, ensuring that service availability is maintained while data consistency is preserved through ongoing replication.
Data Source
AI summary
Embodiments minimize downtime involved in moving a PDB between CDBs by allowing read-write access to the PDB through most of the moving operation, and by transparently forwarding connection requests, for the PDB, from the source CDB to the destination CDB. The files of a source PDB are copied from a source CDB to a destination CDB, during which the source PDB may be in read-write mode. The source PDB is then closed to write operations so that changes to the source PDB cease. Another round of recovery is performed on the PDB clone, which applies all changes that have been performed on the source PDB during the copy operation and the PDB clone is opened for read and write operations. Forwarding information is registered with the source location, which information is used to automatically forward connection requests, received at the source location for the moved PDB, to the destination location.