- 25 Jul, 2025
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RAC Tuning
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Cluster Interconnect Tuning
- Network Configuration: Ensure that the private interconnect network is configured optimally. Use dedicated, high-speed networks (e.g., 10GbE or Infiniband).
- Load Balancing: Utilize Oracle’s interconnect load balancing mechanisms to distribute traffic evenly across available network interfaces.
- UDP Buffer Size: Increase the UDP buffer size to handle increased inter-node communication.
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Cache Fusion Tuning
- Global Cache Latency: Minimize global cache latency by optimizing the interconnect and reducing contention on shared resources.
- Block Transfer Sizes: Use appropriate block transfer sizes to minimize overhead during block transfers between nodes.
- Instance Affinity: Ensure that sessions or workloads are affinitized to specific nodes to reduce the need for block transfers.
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Workload Distribution
- Load Balancing Advisory: Configure the service’s connection load balancing advisory to distribute workload effectively across the cluster.
- Dynamic Resource Allocation: Use dynamic resource allocation policies to ensure that the system adapts to changing workloads in real-time.
- Services & Instances: Assign services to specific instances based on workload characteristics.
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Storage I/O Tuning
- ASM Configuration: Optimize Oracle ASM (Automatic Storage Management) for better I/O performance by configuring appropriate redundancy and striping policies.
- I/O Distribution: Ensure that the I/O workload is evenly distributed across all nodes and storage devices.
- Disk Group Design: Use high-performance storage and configure disk groups for optimal performance.
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CPU and Memory Tuning
- CPU Allocation: Ensure proper CPU allocation across all nodes, avoiding CPU bottlenecks on any particular node.
- Memory Configuration: Tune memory allocation, including the SGA and PGA, to optimize database performance.
- NUMA Optimization: For NUMA (Non-Uniform Memory Access) systems, ensure that memory access patterns are optimized to reduce latency.
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Parallel Execution Tuning
- Parallel Execution Configuration: Optimize parallel execution settings to distribute parallel query execution across nodes effectively.
- Degree of Parallelism (DOP): Set an appropriate DOP based on the system’s capabilities to maximize performance without overloading resources.
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Global Enqueue and Lock Management
- Enqueue Wait Tuning: Reduce enqueue wait events by minimizing contention for shared resources.
- Lock Management: Ensure that locking mechanisms are efficiently managed to reduce contention and bottlenecks.
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SQL Plan Management
- SQL Tuning: Ensure that SQL statements are optimized to reduce resource consumption. Use SQL profiles and baselines to stabilize execution plans.
- Execution Plans: Monitor execution plans for consistency across nodes, ensuring that RAC-specific issues like inter-node block transfers are minimized.
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Diagnostic and Monitoring Tools
- Oracle Enterprise Manager (OEM): Use OEM’s RAC-specific features like the Cluster Database Performance page and Performance Hub to monitor and diagnose performance issues.
- AWR and ASH Reports: Generate AWR and ASH reports to identify top wait events, SQLs, and areas that need tuning.
- GV$ Views: Utilize Global V$ views like GV$INSTANCE, GV$SESSION, GV$ACTIVE_SESSION_HISTORY, etc., to gain insights into cluster-wide performance.
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Application Tuning
- Session Affinity: Ensure that the application tier is tuned to maintain session affinity, reducing unnecessary block transfers between nodes.
- Connection Pools: Tune connection pools to distribute connections evenly across instances and ensure efficient utilization of resources.