Instance-Independent Database Links for Cluster Message Availability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In clustered database systems, propagating non-persistent messages to buffered queues faces challenges due to instance-specific database links, leading to disruptions and unavailability during instance failures, as existing connections fail and re-configuration delays occur.
Innovation Solution
Implementing instance-independent database links and queue-to-instance mapping, where a global listener uses registration information to establish connections with the current owner instance of buffered queues, ensuring seamless message propagation even after instance migrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If instance-specific database links are used to establish connections to buffered queues, then message propagation can be established to specific instances, but connection failures occur during instance migrations causing service unavailability
Solution Approach 1:
The patent applies universality by transforming instance-specific database links into instance-independent database links. The modified dblink configuration no longer contains instance-specific identifiers but instead uses service names that can resolve to any current owner instance of the target queue. This allows the same dblink to function across multiple instances dynamically, enabling the system to adapt to instance migrations while maintaining reliable message propagation.
Solution Approach 2:
The patent implements dynamics by making database link configurations dynamic rather than static. Instead of hardcoding instance identifiers in dblink configurations, the system uses dynamic service name resolution that automatically redirects connections to the current owner instance. This dynamic approach allows the system to adapt to changing instance ownership without requiring manual reconfiguration, thereby maintaining high availability during instance migrations.
2Reliability
If manual re-configuration of database links is performed after instance failure, then connections can be restored to new owner instances, but service downtime occurs during re-configuration
Solution Approach 1:
The patent applies self-service by enabling the system to automatically reconfigure database link connections without manual intervention. When an instance fails and queues are migrated to new owner instances, the instance-independent dblinks automatically resolve service names to the new current owner instances through the data stream infrastructure. This self-service mechanism eliminates manual reconfiguration steps and associated downtime, maintaining continuous message propagation availability.
Solution Approach 2:
The patent implements preliminary action by pre-configuring instance-independent database links with service names that are decoupled from specific instances. This preliminary design choice ensures that when instance migrations occur, the connections are already structured to automatically resolve to new owner instances without requiring immediate reconfiguration. The preliminary abstraction of instance identifiers enables rapid adaptation and minimizes service downtime.
3Adaptability or versatility
If instance-independent database links with service names are used, then automatic connection re-establishment occurs after instance migration, but connection establishment complexity increases
Solution Approach 1:
The patent applies the intermediary principle by introducing service names as an abstraction layer between the database link configuration and the actual instance identifiers. The service name acts as a mediator that the data stream infrastructure resolves to the current owner instance. This intermediary mechanism simplifies the dblink configuration (removing instance-specific details) while the infrastructure handles the resolution complexity, effectively distributing the complexity management between the application layer and the infrastructure layer.
Data Source
AI summary
Techniques are provided for maintaining high propagation availability for non-persistent messages. Destination-to-instance mapping information is provided to a listener process for a cluster database. The destination-to-instance mapping indicates the current owner instance of each single-instance destination within the cluster database. To establish a connection to a single-instance destination, a sending process sends a connection request to the global listener. The connection request identifies the desired destination queue, but not the owner instance of the queue. The global listener for the cluster database uses the destination-to-instance mapping to determine which instance is the current owner of the specified queue, and establishes a connection between the sending process and the appropriate owner instance.