多元索引快速入门

步骤一：创建数据表

多元索引要求数据表的最大版本数为 1，并且数据生命周期为 -1（数据永不过期）或禁止更新数据。本示例将最大版本数设置为 1，将数据生命周期设置为 -1。

private static void createTable(
        SyncClient client, String tableName) {
    TableMeta tableMeta = new TableMeta(tableName);
    tableMeta.addPrimaryKeyColumn(
            new PrimaryKeySchema(
                    "product_id", PrimaryKeyType.STRING));

    TableOptions tableOptions = new TableOptions();
    tableOptions.setTimeToLive(-1);
    tableOptions.setMaxVersions(1);

    client.createTable(
            new CreateTableRequest(tableMeta, tableOptions));
}

步骤二：创建多元索引

为 category 和 price 属性列创建索引字段。索引字段的名称和数据类型必须与数据表中对应属性列保持一致。

private static void createSearchIndex(
        SyncClient client, String tableName, String indexName) {
    IndexSchema indexSchema = new IndexSchema();
    indexSchema.setFieldSchemas(Arrays.asList(
            new FieldSchema("category", FieldType.KEYWORD),
            new FieldSchema("price", FieldType.LONG)));

    CreateSearchIndexRequest request =
            new CreateSearchIndexRequest();
    request.setTableName(tableName);
    request.setIndexName(indexName);
    request.setIndexSchema(indexSchema);
    client.createSearchIndex(request);
}

创建多元索引为异步操作。等待索引状态变为 RUNNING 且同步阶段变为 INCR 后，再查询数据。

private static final int RETRY_ATTEMPTS = 90;
private static final long RETRY_INTERVAL_MILLIS = 1_000L;

private static void waitUntilSearchIndexIsReady(
        SyncClient client, String tableName, String indexName)
        throws InterruptedException {
    for (int attempt = 1; attempt <= RETRY_ATTEMPTS; attempt++) {
        DescribeSearchIndexRequest request =
                new DescribeSearchIndexRequest();
        request.setTableName(tableName);
        request.setIndexName(indexName);
        request.setIncludeSyncStat(true);

        DescribeSearchIndexResponse response =
                client.describeSearchIndex(request);
        if (response.getIndexStatus() != null
                && response.getIndexStatus().indexStatusEnum
                == DescribeSearchIndexResponse.IndexStatusEnum.RUNNING
                && response.getSyncStat() != null
                && response.getSyncStat().getSyncPhase()
                == SyncStat.SyncPhase.INCR) {
            return;
        }
        Thread.sleep(RETRY_INTERVAL_MILLIS);
    }
    throw new IllegalStateException(
            "Search index did not become ready before timeout.");
}

步骤三：写入示例数据

写入 3 条商品数据。其中，product_id 为主键列，category 和 price 为属性列。

private static void putSampleRows(
        SyncClient client, String tableName) {
    putProduct(client, tableName, "product-001", "books", 89L);
    putProduct(client, tableName, "product-002", "books", 129L);
    putProduct(client, tableName, "product-003", "devices", 599L);
}

private static void putProduct(
        SyncClient client,
        String tableName,
        String productId,
        String category,
        long price) {
    PrimaryKey primaryKey =
            PrimaryKeyBuilder.createPrimaryKeyBuilder()
                    .addPrimaryKeyColumn(
                            "product_id",
                            PrimaryKeyValue.fromString(productId))
                    .build();

    RowPutChange rowPutChange =
            new RowPutChange(tableName, primaryKey);
    rowPutChange.addColumn(
            "category", ColumnValue.fromString(category));
    rowPutChange.addColumn(
            "price", ColumnValue.fromLong(price));
    client.putRow(new PutRowRequest(rowPutChange));
}

步骤四：查询数据

使用精确查询匹配 category 列值为 books 的商品。由于数据同步到多元索引需要一定时间，示例会在结果未就绪时重试查询。

private static SearchResponse waitUntilBooksAreQueryable(
        SyncClient client, String tableName, String indexName)
        throws InterruptedException {
    for (int attempt = 1; attempt <= RETRY_ATTEMPTS; attempt++) {
        SearchResponse response =
                queryBooks(client, tableName, indexName);
        if (response.isAllSuccess()
                && response.getTotalCount() == 2L
                && response.getRows().size() == 2) {
            return response;
        }
        Thread.sleep(RETRY_INTERVAL_MILLIS);
    }
    throw new IllegalStateException(
            "Sample rows were not queryable before timeout.");
}

private static SearchResponse queryBooks(
        SyncClient client, String tableName, String indexName) {
    TermQuery termQuery = new TermQuery();
    termQuery.setFieldName("category");
    termQuery.setTerm(ColumnValue.fromString("books"));

    SearchQuery searchQuery = new SearchQuery();
    searchQuery.setQuery(termQuery);
    searchQuery.setLimit(10);
    searchQuery.setTrackTotalCount(
            SearchQuery.TRACK_TOTAL_COUNT);

    SearchRequest.ColumnsToGet columnsToGet =
            new SearchRequest.ColumnsToGet();
    columnsToGet.setReturnAll(true);

    SearchRequest request =
            new SearchRequest(tableName, indexName, searchQuery);
    request.setColumnsToGet(columnsToGet);
    return client.search(request);
}

程序返回的总行数和结果行数均为 2，表示查询成功。