> **Superseded:** This 2026-06-23 DuckDB hot-store plan is historical context.
> Use `docs/target-architecture.md` and
> `docs/superpowers/specs/2026-06-29-vehicle-ingest-redesign.md` for the
> current production architecture: TDengine stores hot history, `sink-archive`
> owns raw bytes, and `event-file-store` / DuckDB are no longer part of the
> current build surface.

# GB32960 History DuckDB Hot Store Implementation Plan

> **For agentic workers:** REQUIRED SUB-SKILL: Use superpowers:subagent-driven-development (recommended) or superpowers:executing-plans to implement this plan task-by-task. Steps use checkbox (`- [ ]`) syntax for tracking.

**Goal:** Replace the current high-write-risk Parquet rewrite history path with a DuckDB hot history store that supports fast `vin + time` queries and full RAW frame replay.

**Architecture:** Add a new `DuckDbHotEventFileStore` implementation behind the existing `EventFileStore` interface, backed by append/upsert DuckDB tables instead of rewriting per-vehicle Parquet files. Keep the current HTTP history API and RAW archive reader intact, then switch `vehicle-history-app` to the hot DuckDB store by configuration.

**Tech Stack:** Java 26, Spring Boot, DuckDB JDBC, JUnit 5, AssertJ, existing Kafka `VehicleEnvelope`, existing `ArchiveStore`.

---

## Scope

This plan implements Phase 1 from `docs/superpowers/specs/2026-06-23-gb32960-production-readiness-design.md`.

Included:

- DuckDB hot event table for `EventFileRecord`.
- Idempotent writes by `event_id`.
- Query by protocol/date/VIN/eventType/eventTime/order/limit.
- Lookup by `rawArchiveUri`.
- Spring configuration to select the hot store.
- Tests that prove history endpoints still replay RAW frames.
- Local verification using the existing `vehicle-history-app`.

Not included in this plan:

- MySQL daily statistics.
- VIN-to-platform local mapping.
- Full telemetry point columnar table.
- Alarm timeline MySQL tables.
- Cold Parquet export.

Those will be separate plans after this foundation lands.

## Files

- Create: `modules/sinks/event-file-store/src/main/java/com/lingniu/ingest/eventfilestore/DuckDbHotEventFileStore.java`
- Create: `modules/sinks/event-file-store/src/test/java/com/lingniu/ingest/eventfilestore/DuckDbHotEventFileStoreTest.java`
- Modify: `modules/sinks/event-file-store/src/main/java/com/lingniu/ingest/eventfilestore/config/EventFileStoreProperties.java`
- Modify: `modules/sinks/event-file-store/src/main/java/com/lingniu/ingest/eventfilestore/config/EventFileStoreAutoConfiguration.java`
- Modify: `modules/sinks/event-file-store/src/test/java/com/lingniu/ingest/eventfilestore/config/EventFileStoreAutoConfigurationTest.java`
- Modify: `modules/apps/vehicle-history-app/src/main/resources/application.yml`
- Modify: `modules/apps/vehicle-history-app/src/test/java/com/lingniu/ingest/historyapp/VehicleHistoryAppDefaultsTest.java`
- Modify: `modules/services/event-history-service/src/test/java/com/lingniu/ingest/eventhistory/Gb32960DecodedFrameServiceTest.java`

## Task 1: Add Hot Store Configuration

**Files:**
- Modify: `modules/sinks/event-file-store/src/main/java/com/lingniu/ingest/eventfilestore/config/EventFileStoreProperties.java`
- Modify: `modules/sinks/event-file-store/src/main/java/com/lingniu/ingest/eventfilestore/config/EventFileStoreAutoConfiguration.java`
- Test: `modules/sinks/event-file-store/src/test/java/com/lingniu/ingest/eventfilestore/config/EventFileStoreAutoConfigurationTest.java`

- [ ] **Step 1: Write the failing auto-configuration test**

Add a test that sets `lingniu.ingest.event-file-store.storage=duckdb-hot` and expects the bean class to be `DuckDbHotEventFileStore`.

```java
@Test
void createsDuckDbHotStoreWhenStorageIsDuckDbHot() {
    contextRunner
            .withPropertyValues(
                    "lingniu.ingest.event-file-store.enabled=true",
                    "lingniu.ingest.event-file-store.storage=duckdb-hot",
                    "lingniu.ingest.event-file-store.path=" + tempDir.resolve("history"))
            .run(context -> assertThat(context)
                    .hasSingleBean(EventFileStore.class)
                    .getBean(EventFileStore.class)
                    .isInstanceOf(DuckDbHotEventFileStore.class));
}
```

- [ ] **Step 2: Run the new test and verify it fails**

Run:

```bash
mvn -pl :event-file-store -Dtest=EventFileStoreAutoConfigurationTest#createsDuckDbHotStoreWhenStorageIsDuckDbHot test
```

Expected: compilation failure because `DuckDbHotEventFileStore` and `storage` property do not exist.

- [ ] **Step 3: Add the `storage` property**

Add to `EventFileStoreProperties`:

```java
/**
 * Storage backend. `duckdb-hot` is the production backend; `parquet-sidecar`
 * keeps the previous implementation available for compatibility tests.
 */
private String storage = "duckdb-hot";

public String getStorage() {
    return storage;
}

public void setStorage(String storage) {
    this.storage = storage;
}
```

- [ ] **Step 4: Switch auto-configuration by storage mode**

Change `eventFileStore(...)` to:

```java
@Bean
@ConditionalOnMissingBean
public EventFileStore eventFileStore(EventFileStoreProperties properties,
                                     ObjectProvider<ObjectMapper> objectMapper) {
    ObjectMapper mapper = mapper(objectMapper);
    Path root = Path.of(properties.getPath());
    ZoneId zoneId = ZoneId.of(properties.getZoneId());
    String storage = properties.getStorage() == null ? "" : properties.getStorage().trim();
    return switch (storage) {
        case "", "duckdb-hot" -> new DuckDbHotEventFileStore(root, zoneId, mapper);
        case "parquet-sidecar" -> new DuckDbParquetEventFileStore(root, zoneId, mapper);
        default -> throw new IllegalStateException(
                "unsupported event-file-store storage: " + properties.getStorage());
    };
}
```

Import `DuckDbHotEventFileStore`.

- [ ] **Step 5: Run configuration tests**

Run:

```bash
mvn -pl :event-file-store -Dtest=EventFileStoreAutoConfigurationTest test
```

Expected: tests pass after the store class exists in Task 2.

## Task 2: Implement DuckDB Hot Store Schema and Writes

**Files:**
- Create: `modules/sinks/event-file-store/src/main/java/com/lingniu/ingest/eventfilestore/DuckDbHotEventFileStore.java`
- Create: `modules/sinks/event-file-store/src/test/java/com/lingniu/ingest/eventfilestore/DuckDbHotEventFileStoreTest.java`

- [ ] **Step 1: Write failing append/query/idempotency tests**

Create `DuckDbHotEventFileStoreTest`:

```java
class DuckDbHotEventFileStoreTest {

    @TempDir
    Path tempDir;

    @Test
    void appendsRecordsAndQueriesByVinTypeAndTime() throws Exception {
        EventFileStore store = store();
        store.append(rawRecord("raw-1", "VIN001", "2026-06-23T01:00:00Z"));
        store.append(rawRecord("raw-2", "VIN002", "2026-06-23T01:00:01Z"));
        store.append(rawRecord("raw-3", "VIN001", "2026-06-23T01:00:02Z"));

        EventFileQuery query = new EventFileQuery(
                ProtocolId.GB32960,
                LocalDate.parse("2026-06-23"),
                LocalDate.parse("2026-06-23"),
                Instant.parse("2026-06-23T01:00:00Z"),
                Instant.parse("2026-06-23T01:00:03Z"),
                EventFileQuery.Order.DESC,
                2,
                "VIN001",
                "RAW_ARCHIVE");

        assertThat(store.query(query))
                .extracting(EventFileRecord::eventId)
                .containsExactly("raw-3", "raw-1");
    }

    @Test
    void appendAllIsIdempotentByEventId() throws Exception {
        EventFileStore store = store();
        EventFileRecord original = rawRecord("same-id", "VIN001", "2026-06-23T01:00:00Z");
        EventFileRecord replacement = new EventFileRecord(
                "same-id",
                ProtocolId.GB32960,
                "RAW_ARCHIVE",
                "VIN001",
                Instant.parse("2026-06-23T01:00:05Z"),
                Instant.parse("2026-06-23T01:00:06Z"),
                "archive://replacement.bin",
                Map.of("source", "replacement"),
                "{\"replacement\":true}");

        store.appendAll(List.of(original, replacement));

        assertThat(store.query(new EventFileQuery(
                ProtocolId.GB32960,
                LocalDate.parse("2026-06-23"),
                LocalDate.parse("2026-06-23"),
                EventFileQuery.Order.ASC,
                10,
                "VIN001",
                "RAW_ARCHIVE")))
                .singleElement()
                .satisfies(record -> {
                    assertThat(record.eventId()).isEqualTo("same-id");
                    assertThat(record.rawArchiveUri()).isEqualTo("archive://replacement.bin");
                });
    }

    @Test
    void findsRecordByRawArchiveUri() throws Exception {
        EventFileStore store = store();
        EventFileRecord record = rawRecord("raw-uri", "VIN001", "2026-06-23T01:00:00Z");
        store.append(record);

        EventFileRecord found = store.findByRawArchiveUri(record.rawArchiveUri());

        assertThat(found).isNotNull();
        assertThat(found.eventId()).isEqualTo("raw-uri");
    }

    private EventFileStore store() {
        return new DuckDbHotEventFileStore(tempDir, ZoneId.of("Asia/Shanghai"), new ObjectMapper());
    }

    private static EventFileRecord rawRecord(String id, String vin, String eventTime) {
        return new EventFileRecord(
                id,
                ProtocolId.GB32960,
                "RAW_ARCHIVE",
                vin,
                Instant.parse(eventTime),
                Instant.parse(eventTime).plusMillis(100),
                "archive://" + id + ".bin",
                Map.of("platformAccount", "Hyundai", "command", "REALTIME_REPORT"),
                "{\"eventId\":\"" + id + "\"}");
    }
}
```

- [ ] **Step 2: Run the test and verify it fails**

Run:

```bash
mvn -pl :event-file-store -Dtest=DuckDbHotEventFileStoreTest test
```

Expected: compilation failure because `DuckDbHotEventFileStore` does not exist.

- [ ] **Step 3: Create the hot store class**

Create `DuckDbHotEventFileStore` with this structure:

```java
public final class DuckDbHotEventFileStore implements EventFileStore {

    private static final TypeReference<Map<String, String>> STRING_MAP = new TypeReference<>() {};

    private final Path root;
    private final Path dbPath;
    private final ZoneId partitionZone;
    private final ObjectMapper objectMapper;
    private volatile boolean initialized;

    public DuckDbHotEventFileStore(Path root, ZoneId partitionZone) {
        this(root, partitionZone, new ObjectMapper());
    }

    public DuckDbHotEventFileStore(Path root, ZoneId partitionZone, ObjectMapper objectMapper) {
        if (root == null) {
            throw new IllegalArgumentException("root must not be null");
        }
        this.root = root.toAbsolutePath();
        this.dbPath = this.root.resolve("events.duckdb");
        this.partitionZone = partitionZone == null ? ZoneId.of("Asia/Shanghai") : partitionZone;
        this.objectMapper = objectMapper == null ? new ObjectMapper() : objectMapper;
    }

    @Override
    public synchronized void appendAll(List<EventFileRecord> records) throws IOException {
        if (records == null || records.isEmpty()) {
            return;
        }
        ensureInitialized();
        try (Connection connection = DriverManager.getConnection(jdbcUrl())) {
            connection.setAutoCommit(false);
            try {
                upsertRecords(connection, records);
                connection.commit();
            } catch (SQLException | IOException e) {
                connection.rollback();
                throw e;
            } finally {
                connection.setAutoCommit(true);
            }
        } catch (SQLException e) {
            throw new IOException("write duckdb hot event store failed", e);
        }
    }

    @Override
    public List<EventFileRecord> query(EventFileQuery query) throws IOException {
        ensureInitialized();
        // Implement in Task 3.
        return List.of();
    }

    @Override
    public EventFileRecord findByRawArchiveUri(String rawArchiveUri) throws IOException {
        ensureInitialized();
        // Implement in Task 3.
        return null;
    }
}
```

- [ ] **Step 4: Add schema initialization**

Add:

```java
private void ensureInitialized() throws IOException {
    if (initialized) {
        return;
    }
    synchronized (this) {
        if (initialized) {
            return;
        }
        Files.createDirectories(root);
        try (Connection connection = DriverManager.getConnection(jdbcUrl());
             Statement statement = connection.createStatement()) {
            statement.execute("""
                    CREATE TABLE IF NOT EXISTS event_records (
                        event_id VARCHAR PRIMARY KEY,
                        protocol VARCHAR NOT NULL,
                        event_type VARCHAR NOT NULL,
                        vin VARCHAR NOT NULL,
                        event_time_ms BIGINT NOT NULL,
                        ingest_time_ms BIGINT NOT NULL,
                        partition_date DATE NOT NULL,
                        raw_archive_uri VARCHAR NOT NULL,
                        metadata_json VARCHAR NOT NULL,
                        payload_json VARCHAR NOT NULL
                    )
                    """);
            statement.execute("""
                    CREATE INDEX IF NOT EXISTS event_records_protocol_date_time_idx
                    ON event_records(protocol, partition_date, event_time_ms)
                    """);
            statement.execute("""
                    CREATE INDEX IF NOT EXISTS event_records_vin_date_time_idx
                    ON event_records(protocol, vin, partition_date, event_time_ms)
                    """);
            statement.execute("""
                    CREATE INDEX IF NOT EXISTS event_records_vin_type_date_time_idx
                    ON event_records(protocol, vin, event_type, partition_date, event_time_ms)
                    """);
            statement.execute("""
                    CREATE INDEX IF NOT EXISTS event_records_raw_archive_uri_idx
                    ON event_records(raw_archive_uri)
                    """);
            initialized = true;
        } catch (SQLException e) {
            throw new IOException("initialize duckdb hot event store failed", e);
        }
    }
}
```

- [ ] **Step 5: Add idempotent batch upsert**

Use DuckDB `INSERT OR REPLACE` inside one transaction:

```java
private void upsertRecords(Connection connection, List<EventFileRecord> records)
        throws SQLException, IOException {
    try (PreparedStatement ps = connection.prepareStatement("""
            INSERT OR REPLACE INTO event_records VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
            """)) {
        for (EventFileRecord record : records) {
            ps.setString(1, record.eventId());
            ps.setString(2, record.protocol().name());
            ps.setString(3, record.eventType());
            ps.setString(4, record.vin());
            ps.setLong(5, record.eventTime().toEpochMilli());
            ps.setLong(6, record.ingestTime().toEpochMilli());
            ps.setString(7, LocalDate.ofInstant(record.eventTime(), partitionZone).toString());
            ps.setString(8, record.rawArchiveUri());
            ps.setString(9, objectMapper.writeValueAsString(record.metadata()));
            ps.setString(10, record.payloadJson());
            ps.addBatch();
        }
        ps.executeBatch();
    }
}
```

- [ ] **Step 6: Run the hot store tests**

Run:

```bash
mvn -pl :event-file-store -Dtest=DuckDbHotEventFileStoreTest test
```

Expected: query tests still fail until Task 3 implements reads; append initialization should compile.

## Task 3: Implement Hot Store Queries and Raw URI Lookup

**Files:**
- Modify: `modules/sinks/event-file-store/src/main/java/com/lingniu/ingest/eventfilestore/DuckDbHotEventFileStore.java`
- Test: `modules/sinks/event-file-store/src/test/java/com/lingniu/ingest/eventfilestore/DuckDbHotEventFileStoreTest.java`

- [ ] **Step 1: Implement `query(EventFileQuery)`**

Use prepared statements for every external value:

```java
@Override
public List<EventFileRecord> query(EventFileQuery query) throws IOException {
    ensureInitialized();
    String order = query.order() == EventFileQuery.Order.DESC ? "DESC" : "ASC";
    StringBuilder where = new StringBuilder("""
            WHERE protocol = ?
              AND partition_date BETWEEN CAST(? AS DATE) AND CAST(? AS DATE)
            """);
    if (query.vin() != null) {
        where.append("  AND vin = ?\n");
    }
    if (query.eventType() != null) {
        where.append("  AND event_type = ?\n");
    }
    if (query.eventTimeFrom() != null) {
        where.append("  AND event_time_ms >= ?\n");
    }
    if (query.eventTimeTo() != null) {
        where.append("  AND event_time_ms <= ?\n");
    }
    String sql = """
            SELECT event_id, protocol, event_type, vin, event_time_ms, ingest_time_ms,
                   raw_archive_uri, metadata_json, payload_json
            FROM event_records
            %s
            ORDER BY event_time_ms %s, ingest_time_ms %s, event_id %s
            LIMIT ?
            """.formatted(where, order, order, order);
    try (Connection connection = DriverManager.getConnection(jdbcUrl());
         PreparedStatement ps = connection.prepareStatement(sql)) {
        bindQuery(ps, query);
        try (ResultSet rs = ps.executeQuery()) {
            List<EventFileRecord> out = new ArrayList<>();
            while (rs.next()) {
                out.add(record(rs));
            }
            return out;
        }
    } catch (SQLException e) {
        throw new IOException("query duckdb hot event store failed", e);
    }
}
```

- [ ] **Step 2: Add query binding helper**

```java
private static void bindQuery(PreparedStatement ps, EventFileQuery query) throws SQLException {
    int index = 1;
    ps.setString(index++, query.protocol().name());
    ps.setString(index++, query.dateFrom().toString());
    ps.setString(index++, query.dateTo().toString());
    if (query.vin() != null) {
        ps.setString(index++, query.vin());
    }
    if (query.eventType() != null) {
        ps.setString(index++, query.eventType());
    }
    if (query.eventTimeFrom() != null) {
        ps.setLong(index++, query.eventTimeFrom().toEpochMilli());
    }
    if (query.eventTimeTo() != null) {
        ps.setLong(index++, query.eventTimeTo().toEpochMilli());
    }
    ps.setInt(index, query.limit());
}
```

- [ ] **Step 3: Implement `findByRawArchiveUri`**

```java
@Override
public EventFileRecord findByRawArchiveUri(String rawArchiveUri) throws IOException {
    if (rawArchiveUri == null || rawArchiveUri.isBlank()) {
        return null;
    }
    ensureInitialized();
    try (Connection connection = DriverManager.getConnection(jdbcUrl());
         PreparedStatement ps = connection.prepareStatement("""
                 SELECT event_id, protocol, event_type, vin, event_time_ms, ingest_time_ms,
                        raw_archive_uri, metadata_json, payload_json
                 FROM event_records
                 WHERE raw_archive_uri = ?
                 ORDER BY event_type = 'RAW_ARCHIVE' DESC, ingest_time_ms DESC, event_id DESC
                 LIMIT 1
                 """)) {
        ps.setString(1, rawArchiveUri);
        try (ResultSet rs = ps.executeQuery()) {
            return rs.next() ? record(rs) : null;
        }
    } catch (SQLException e) {
        throw new IOException("query duckdb hot store by raw archive uri failed", e);
    }
}
```

- [ ] **Step 4: Add record mapper and helpers**

```java
private EventFileRecord record(ResultSet rs) throws SQLException, IOException {
    return new EventFileRecord(
            rs.getString("event_id"),
            protocol(rs.getString("protocol")),
            rs.getString("event_type"),
            rs.getString("vin"),
            Instant.ofEpochMilli(rs.getLong("event_time_ms")),
            Instant.ofEpochMilli(rs.getLong("ingest_time_ms")),
            rs.getString("raw_archive_uri"),
            readMetadata(rs.getString("metadata_json")),
            rs.getString("payload_json"));
}

private Map<String, String> readMetadata(String json) throws IOException {
    if (json == null || json.isBlank()) {
        return Map.of();
    }
    return objectMapper.readValue(json, STRING_MAP);
}

private static ProtocolId protocol(String value) {
    if (value == null || value.isBlank()) {
        return ProtocolId.UNKNOWN;
    }
    try {
        return ProtocolId.valueOf(value);
    } catch (IllegalArgumentException ex) {
        return ProtocolId.UNKNOWN;
    }
}

private String jdbcUrl() {
    return "jdbc:duckdb:" + dbPath;
}
```

- [ ] **Step 5: Run hot store tests**

Run:

```bash
mvn -pl :event-file-store -Dtest=DuckDbHotEventFileStoreTest test
```

Expected: all `DuckDbHotEventFileStoreTest` tests pass.

## Task 4: Preserve Legacy Store Tests and Update Defaults

**Files:**
- Modify: `modules/sinks/event-file-store/src/test/java/com/lingniu/ingest/eventfilestore/DuckDbParquetEventFileStoreTest.java`
- Modify: `modules/apps/vehicle-history-app/src/main/resources/application.yml`
- Modify: `modules/apps/vehicle-history-app/src/test/java/com/lingniu/ingest/historyapp/VehicleHistoryAppDefaultsTest.java`

- [ ] **Step 1: Keep Parquet tests explicitly legacy**

No behavior change is needed in `DuckDbParquetEventFileStoreTest`; leave it instantiating `DuckDbParquetEventFileStore` directly. Add a class comment:

```java
/**
 * Compatibility coverage for the legacy Parquet sidecar backend.
 * Production history uses DuckDbHotEventFileStore through auto-configuration.
 */
class DuckDbParquetEventFileStoreTest {
```

- [ ] **Step 2: Set vehicle-history-app storage default**

Add to `modules/apps/vehicle-history-app/src/main/resources/application.yml`:

```yaml
    event-file-store:
      enabled: ${EVENT_FILE_STORE_ENABLED:true}
      storage: ${EVENT_FILE_STORE_STORAGE:duckdb-hot}
      path: ${EVENT_FILE_STORE_PATH:./target/event-store/}
      zone-id: ${EVENT_FILE_STORE_ZONE_ID:Asia/Shanghai}
      batch-size: ${EVENT_FILE_STORE_BATCH_SIZE:1000}
      flush-interval-millis: ${EVENT_FILE_STORE_FLUSH_INTERVAL_MILLIS:1000}
```

Keep existing indentation and only add `storage`; if `batch-size` already exists, update it to `1000`.

- [ ] **Step 3: Update app default test**

In `VehicleHistoryAppDefaultsTest`, assert:

```java
assertThat(context.getEnvironment()
        .getProperty("lingniu.ingest.event-file-store.storage"))
        .isEqualTo("duckdb-hot");
```

- [ ] **Step 4: Run app default tests**

Run:

```bash
mvn -pl :vehicle-history-app -Dtest=VehicleHistoryAppDefaultsTest test
```

Expected: default configuration test passes.

## Task 5: Verify History Ingest Still Archives RAW Bytes

**Files:**
- Modify: `modules/services/event-history-service/src/test/java/com/lingniu/ingest/eventhistory/EventHistoryEnvelopeIngestorTest.java`
- Test: `modules/services/event-history-service/src/test/java/com/lingniu/ingest/eventhistory/Gb32960DecodedFrameServiceTest.java`

- [ ] **Step 1: Add an integration-style test using the hot store**

Add a test that writes a RAW envelope through `EventHistoryEnvelopeIngestor` into `DuckDbHotEventFileStore`, then finds it by URI.

```java
@Test
void rawArchiveEnvelopeCanBeFoundFromDuckDbHotStoreByUri(@TempDir Path tempDir) throws Exception {
    EventFileStore store = new DuckDbHotEventFileStore(tempDir, ZoneId.of("Asia/Shanghai"), OBJECT_MAPPER);
    CapturingArchiveStore archive = new CapturingArchiveStore();
    EventHistoryEnvelopeIngestor ingestor =
            new EventHistoryEnvelopeIngestor(store, new TelemetryEnvelopeRecordMapper(), archive);
    String rawArchiveKey = "2026/06/23/GB32960/VINRAW001/raw-event-hot.bin";
    String rawArchiveUri = "archive://" + rawArchiveKey;
    byte[] rawBytes = new byte[]{0x23, 0x23, 0x02, 0x01};

    VehicleEnvelope envelope = VehicleEnvelope.newBuilder()
            .setSchemaVersion("1.0")
            .setEventId("raw-event-hot")
            .setVin("VINRAW001")
            .setSource("GB32960")
            .setProtocolVersion("V2016")
            .setEventTimeMs(1_782_112_400_000L)
            .setIngestTimeMs(1_782_112_401_000L)
            .putMetadata(RawArchiveKeys.META_KEY, rawArchiveKey)
            .putMetadata(RawArchiveKeys.META_URI, rawArchiveUri)
            .setRawArchive(RawArchiveRef.newBuilder()
                    .setUri(rawArchiveUri)
                    .setSizeBytes(rawBytes.length)
                    .setData(ByteString.copyFrom(rawBytes))
                    .build())
            .build();

    EnvelopeIngestResult result = ingestor.tryIngest(envelope.toByteArray());

    assertThat(result.status()).isEqualTo(EnvelopeIngestResult.Status.STORED);
    assertThat(store.findByRawArchiveUri(rawArchiveUri))
            .isNotNull()
            .extracting(EventFileRecord::eventId)
            .isEqualTo("raw-event-hot");
    assertThat(archive.bytesByKey).containsEntry(rawArchiveKey, rawBytes);
}
```

- [ ] **Step 2: Run the event history ingestor test**

Run:

```bash
mvn -pl :event-history-service -Dtest=EventHistoryEnvelopeIngestorTest test
```

Expected: test passes.

- [ ] **Step 3: Run decoded frame service tests**

Run:

```bash
mvn -pl :event-history-service -Dtest=Gb32960DecodedFrameServiceTest test
```

Expected: existing replay/snapshot tests pass. If they use a fake store, no change is needed.

## Task 6: Full Module Verification

**Files:**
- No source changes unless failures expose missing imports or config assertions.

- [ ] **Step 1: Run sink module tests**

Run:

```bash
mvn -pl :event-file-store test
```

Expected: all event-file-store tests pass, including both hot and legacy stores.

- [ ] **Step 2: Run event-history-service tests**

Run:

```bash
mvn -pl :event-history-service test
```

Expected: all event-history-service tests pass.

- [ ] **Step 3: Package vehicle-history-app**

Run:

```bash
mvn -pl :vehicle-history-app -am package -DskipTests
```

Expected: package succeeds.

## Task 7: Local Runtime Verification

**Files:**
- No committed source changes.

- [ ] **Step 1: Stop any old history service on port 20200**

Run:

```bash
lsof -tiTCP:20200 -sTCP:LISTEN | xargs -r kill
```

Expected: no command output, or the old process exits.

- [ ] **Step 2: Start vehicle-history-app with hot DuckDB store**

Run:

```bash
EVENT_FILE_STORE_STORAGE=duckdb-hot \
EVENT_FILE_STORE_PATH=./target/live-history-event-store \
SINK_ARCHIVE_PATH=./target/live-history-archive \
KAFKA_BROKERS=114.55.58.251:9092 \
KAFKA_CONSUMER_ENABLED=true \
KAFKA_GROUP_HISTORY=vehicle-history-hot-$(date +%Y%m%d%H%M%S) \
java --sun-misc-unsafe-memory-access=allow \
  -jar modules/apps/vehicle-history-app/target/vehicle-history-app.jar
```

Expected:

- app starts on `http://127.0.0.1:20200`;
- logs show Kafka consumer subscribed;
- `target/live-history-event-store/events.duckdb` is created.

- [ ] **Step 3: Verify health**

Run:

```bash
curl -sS http://127.0.0.1:20200/actuator/health
```

Expected:

```json
{"status":"UP"}
```

- [ ] **Step 4: Verify a recent VIN query**

Run with a VIN observed in live archive:

```bash
curl -sS 'http://127.0.0.1:20200/api/event-history/gb32960/telemetry-snapshots?vin=LNXNEGRR9SR318194&platformAccount=Hyundai&dateFrom=2026-06-23&dateTo=2026-06-24&order=DESC&limit=3'
```

Expected:

- response is a JSON array;
- if live traffic for that VIN exists after service start, at least one snapshot appears;
- `rawArchiveUris` point to existing files under `target/live-history-archive`.

- [ ] **Step 5: Verify raw frame replay**

Use one `rawArchiveUri` from Step 4:

```bash
curl -sS 'http://127.0.0.1:20200/api/event-history/gb32960/frame?rawArchiveUri=archive://REPLACE_ME&platformAccount=Hyundai'
```

Expected:

- response contains `vin`, `command`, `eventTime`, and parsed `blocks`;
- no `raw archive is missing` warning for the selected URI.

## Self-Review Checklist

- [ ] The new hot store does not rewrite Parquet files on every append.
- [ ] `appendAll` writes one batch in one transaction.
- [ ] Duplicate `event_id` replay is idempotent.
- [ ] Existing history HTTP APIs still use `EventFileStore`, so controller contracts are unchanged.
- [ ] RAW bytes still land in `ArchiveStore`.
- [ ] `findByRawArchiveUri` is backed by DuckDB index.
- [ ] No MySQL credential, RDS host, username, or password appears in the plan or source files.
- [ ] This plan does not claim the full production goal is complete; it only lands the history foundation.