4-2 Oracle Fusion Middleware Configuring and Managing JDBC Data Sources for Oracle WebLogic Server
Figure 4–1 GridLink Data Source Connectivity
A GridLink data source includes the features of generic data sources plus the following support for Oracle RAC:
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Section 4.1.1, Fast Connection Failover
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Section 4.1.2, Runtime Connection Load Balancing
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Section 4.1.3, Graceful Handling for Oracle RAC Outages
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Section 4.1.4, XA Affinity
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Section 4.1.5, SCAN Addresses
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Section 4.1.6, Secure Communication using Oracle Wallet.
4.1.1 Fast Connection Failover
A GridLink data source uses Fast Connection Failover and responds to Oracle RAC events using ONS. This ensures that the connection pool in the GridLink data source
contains valid connections including reserved connections without the need to poll and test connections.
Using GridLink Data Sources 4-3
Figure 4–2 Fast Connection Failover
A GridLink data source uses Fast Connection Failover to:
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Provide rapid failure detection.
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Abort and remove invalid connections from the connection pool.
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Perform graceful shutdown for planned and unplanned Oracle RAC node outages. See
Section 4.1.3, Graceful Handling for Oracle RAC Outages.
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Adapt to changes in topology, such as addingor removing a node.
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Distribute runtime work requests to all active Oracle RAC instances, including those rejoining a cluster.
See Fast Connection Failover in the Oracle Database JDBC Developers Guide and Reference.
4.1.2 Runtime Connection Load Balancing
GridLink data sources provide load balancing in XA and non-XA environments. GridLink data sources use runtime connection load balancing to distribute connections
to Oracle RAC instances based on Oracle FAN events issued by the database. This simplifies data source configuration and improves performance as the database drives
load balancing of connections through the GridLink data source, independent of the database topology.
Runtime Connection Load Balancing allows WebLogic Server to:
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Adjust the distribution of work based on back end node capacities such as CPU, availability, and response time.
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React to changes in Oracle RAC topology.
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Manage pooled connections for high performance and scalability.
4-4 Oracle Fusion Middleware Configuring and Managing JDBC Data Sources for Oracle WebLogic Server
Figure 4–3 Runtime Connection Load Balancing
If FAN is not enabled, GridLink data sources use a round-robin load balancing algorithm to allocate connections to Oracle RAC nodes.
4.1.3 Graceful Handling for Oracle RAC Outages
