This commit addresses critical N+1 query performance issues identified in
the reward simulation system. The optimizations significantly reduce database
round trips and improve performance when processing large datasets.
**Key Optimizations:**
1. **Batch Identity Key Lookups**
- Added `get_mixnode_identity_keys_batch()` and `get_gateway_identity_keys_batch()`
- Updated simulation performance conversion to use batch operations
- Reduced from N individual queries to 2 batch queries
2. **Batch Node Classification**
- Added `classify_nodes_batch()` method for mixnode/gateway determination
- Updated reliability calculation methods to use batch classification
- Reduced from N individual lookups to 2 batch queries
3. **Batch Epoch Metadata Enhancement**
- Added `count_simulated_node_performance_for_epochs_batch()`
- Added `get_available_calculation_methods_for_epochs_batch()`
- Updated API handlers to use batch operations for metadata enhancement
- Reduced from 2N queries to 2 batch queries for epoch data
4. **Bulk Insert Optimizations**
- Converted individual INSERT operations to use `sqlx::QueryBuilder::push_values()`
- Optimized simulation data insertion methods
- Eliminated transaction overhead from individual inserts
**Performance Impact:**
- Before: N+2N database queries for N nodes/epochs
- After: 2+2 batch queries regardless of dataset size
- Significant performance improvement for large simulation datasets
All changes maintain backward compatibility while providing substantial
performance benefits for the reward simulation system.
durch
4f7fa557d5