# Phase 2: Optimization and Fixes

- **Status**: Completed
- **Author**: AI Assistant
- **Created**: 2026-02-04

## Context

Following the initial stabilization, several issues were identified:
1.  **Missing Command Support**: The system did not recognize command word `0x0E`, which shares the same structure as `0x36`.
2.  **Bootstrap Instability**: On Windows, restarting the service frequently caused `EADDRINUSE` errors when connecting to PostgreSQL due to ephemeral port exhaustion.
3.  **Performance Bottleneck**: The Kafka consumer could not keep up with the backlog using single-row inserts and low parallelism, and scaling horizontal instances was restricted.

## Implemented Changes

### 1. 0x0E Command Support
- **Goal**: Enable processing of `0x0E` command word.
- **Implementation**:
    -   Updated `resolveMessageType` in `src/processor/index.js` to map `0x0E` to the same handler as `0x36`.
    -   Added unit tests in `tests/processor.test.js` to verify `0x0E` parsing for status and fault reports.

### 2. Bootstrap Retry Logic
- **Goal**: Prevent service startup failure due to transient port conflicts.
- **Implementation**:
    -   Modified `src/db/initializer.js` to catch `EADDRINUSE` errors during the initial database connection.
    -   Added a retry mechanism: max 5 retries with 1-second backoff.

### 3. High Throughput Optimization (Batch Processing)
- **Goal**: Resolve Kafka backlog without adding more service instances.
- **Implementation**:
    -   **Batch Processor**: Created `src/db/batchProcessor.js` to buffer messages in memory.
    -   **Strategy**: Messages are flushed to DB when buffer size reaches 500 or every 1 second.
    -   **Config Update**: Increased default `KAFKA_MAX_IN_FLIGHT` from 50 to 500 in `src/config/config.js` to align with batch size.
    -   **Integration**: Refactored `src/index.js` and `src/processor/index.js` to decouple parsing from insertion, allowing `BatchProcessor` to handle the write operations.

## Impact
- **Throughput**: Significantly increased database write throughput via batching.
- **Reliability**: Service is resilient to port conflicts on restart.
- **Functionality**: `0x0E` messages are now correctly processed and stored.
