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docs: align jt808 mileage metric design

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lingniu
2026-07-01 09:36:57 +08:00
parent d9329f4364
commit 74fbdd2b1a
2 changed files with 41 additions and 9 deletions
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docs/superpowers/plans/2026-06-30-kafka-streaming-mileage.md
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@@ -2,14 +2,14 @@
## Current Goal
Consume JT808 Kafka location events, keep rolling daily state, and write the derived daily mileage into the common vehicle-stat metric repository.
Consume JT808 Kafka location events and write the derived daily mileage into the common vehicle-stat metric repository.
## Current Design
- Source topic: `vehicle.event.jt808.v1`
- Runtime app: `vehicle-analytics-app`
- Runtime state: Redis `Jt808MileageStateStore`
- Metric output: `VehicleStatRepository.saveDailyStat(...)`
- Runtime state: none outside `vehicle_stat_metric`
- Metric output: `VehicleStatRepository.recordDailyMileageSample(...)`
- Production metric storage: JDBC/MySQL `vehicle_stat_metric`
- Date boundary: `Asia/Shanghai`
- Calculation method: `JT808_TOTAL_MILEAGE_DIFF`
@@ -20,7 +20,14 @@ JT808 daily mileage is calculated only from the GPS total mileage reported by JT
daily_mileage_km = last_total_mileage_km - first_total_mileage_km
```
The stream saves a metric only when at least two ordered location points for the same vehicle and local day contain valid `total_mileage_km`. Negative differences are treated as invalid and are not written.
The first valid local-day sample writes `daily_mileage_km=0.0`. Later samples update the same metric row with:
```text
metric_value = latest_total_mileage_km - first_total_mileage_km
metric_key = daily_mileage_km
```
The first and latest GPS total mileage values stay on that same metric row as calculation source columns so restarts recover from MySQL without Redis or another state table.
## Runtime Properties
@@ -32,12 +39,8 @@ VEHICLE_STAT_REPOSITORY_TYPE=jdbc
MYSQL_JDBC_URL=<jdbc-url>
MYSQL_USERNAME=<user>
MYSQL_PASSWORD=<password>
REDIS_HOST=<host>
REDIS_PORT=6379
REDIS_DATABASE=50
REDIS_PASSWORD=<password>
```
## Notes
Do not create or write a protocol-specific JT808 daily-mileage table. Do not add GPS segment distance, speed integral, or jump-filter state back into this path unless the mileage definition changes again.
Do not create or write a protocol-specific JT808 daily-mileage table. Do not add distance accumulation, integral calculation, Redis state, or memory state back into this path unless the mileage definition changes again.