54 lines
1.7 KiB
Markdown
54 lines
1.7 KiB
Markdown
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# ExF Latency Options
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## Current: 500ms Standard
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- **HZ Push Interval**: 0.5 seconds
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- **Latency**: Data in HZ within 500ms of change
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- **CPU**: Minimal (~1%)
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- **Use Case**: Standard 5-second Alpha Engine scans
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## Option 1: 100ms Fast (5x faster)
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- **HZ Push Interval**: 0.1 seconds
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- **Latency**: Data in HZ within 100ms of change
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- **CPU**: Low (~2-3%)
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- **Use Case**: High-frequency Alpha Engine
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- **Run**: `python exf_fetcher_flow_fast.py`
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## Option 2: Event-Driven (Near-zero)
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- **HZ Push**: Immediately on indicator change
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- **Latency**: <10ms for critical indicators
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- **CPU**: Minimal (only push on change)
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- **Use Case**: Ultra-low-latency requirements
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- **Run**: `python realtime_exf_service_hz_events.py`
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## Recommendation
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For your setup with 5-second Alpha Engine scans:
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- **Standard (500ms)**: ✅ Sufficient - 10x oversampling
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- **Fast (100ms)**: ⚡ Better - 50x oversampling, minimal overhead
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- **Event-driven**: 🚀 Best - Near-zero latency, efficient
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## Quick Start
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```bash
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cd /mnt/dolphinng5_predict/prod
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# Option 1: Standard (current)
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./start_exf.sh restart
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# Option 2: Fast (100ms)
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nohup python exf_fetcher_flow_fast.py --warmup 10 > /var/log/exf_fast.log 2>&1 &
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# Option 3: Event-driven
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nohup python realtime_exf_service_hz_events.py --warmup 10 > /var/log/exf_event.log 2>&1 &
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```
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## Data Freshness by Option
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| Option | Max Latency | Use Case |
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|--------|-------------|----------|
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| Standard | 500ms | Normal operation |
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| Fast | 100ms | HFT-style trading |
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| Event-Driven | <10ms | Ultra-HFT, market making |
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**Note**: The in-memory cache is updated every 0.5s for critical indicators regardless of HZ push rate. The push rate only affects how quickly data appears in Hazelcast.
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