GridLink data sources are designed for use with an Oracle RAC database. By using the Fast Connection Failover (FCF) pattern, GridLink data sources can quickly react when a RAC node goes down. Which two statements are true?

GridLink data sources in WebLogic Server are specifically designed for Oracle RAC databases and utilize Fast Connection Failover (FCF). The core of FCF is its event-driven architecture. It relies on the Oracle Notification Service (ONS) to publish notifications about the status of RAC nodes (e.g., UP or DOWN events). The GridLink data source's underlying JDBC driver subscribes to these ONS events, allowing it to react immediately to failures without waiting for network timeouts or polling. To establish this connection, the GridLink data source must be configured with the connection details for the Oracle RAC cluster, typically using the Single Client Access Name (SCAN) address.

B. The speed of FCF comes from the immediate, event-based notifications from ONS, not from using low network timeouts, which can be unreliable for failure detection.
C. FCF is an event-driven (push) mechanism. It does not poll the database connections; it listens for events, which is significantly faster and more efficient than polling.
E. GridLink data sources require a specific version of the Oracle Thin driver that is RAC-aware and supports FCF and ONS (typically Oracle Database 11g or later). Not just any Thin driver can be used.

1. Oracle Fusion Middleware

Administering JDBC Data Sources for Oracle WebLogic Server

12c (12.2.1.4.0)

Chapter 10: Using GridLink Data Sources.

Section: "Fast Connection Failover": "A GridLink data source uses Oracle Notification Service (ONS) to subscribe to and receive Fast Application Notification (FAN) events... When a RAC node fails

the Oracle driver receives a FAN event through ONS and immediately cleans up all invalid connections to the failed node." This directly supports option A and refutes B and C.

Section: "Creating a GridLink Data Source": This section details the configuration steps

which include providing the "ONS client configuration" and the "JDBC URL

" typically using a SCAN address. This demonstrates the requirement to configure the database server connection

supporting option D.

2. Oracle Database

JDBC Developer's Guide

19c

Chapter 13: Fast Connection Failover.

Section: "Overview of Fast Connection Failover": "Fast Connection Failover is a feature of the JDBC client. It uses the underlying Oracle Notification Services (ONS) to provide immediate notification to the JDBC client when a node in a Real Application Clusters (RAC) cluster is no longer available." This confirms the role of ONS as described in option A.

Section: "Enabling Fast Connection Failover": This section notes the requirement for a compatible Oracle JDBC driver (e.g.

ojdbc8.jar)

which refutes the claim in option E that any Thin driver is sufficient.