在创建多元索引时可以选择部分主键列作为路由字段,在进行索引数据写入时,会根据路由字段的值计算索引数据的分布位置,路由字段的值相同的记录会被索引到相同的数据分区中。
使用方法
- 在创建索引时,指定一个或多个路由字段。
您在创建多元索引时指定了路由字段后,索引数据的读写都会使用该路由字段进行定位,不能动态改变。如果想使用系统默认路由(即主键列路由)或者重新指定其他字段为路由字段,您需要重建索引。
说明 路由字段只能是表格存储的主键列。 - 在索引查询时,在查询请求中指定路由字段值。
查询时使用路由,定向搜索指定数据分区,可以减少长尾对延迟的影响。对于自定义路由的查询请求,都要求用户提供路由字段。如不指定,虽然查询结果一样,但查询时会访问无关的数据分区,浪费系统资源,增加访问延迟。
示例代码
private static void testRoute(SyncClient client) throws InterruptedException {
//创建表
TableMeta meta = new TableMeta("order");
meta.addPrimaryKeyColumn("order_id",PrimaryKeyType.STRING);
meta.addPrimaryKeyColumn("user_id",PrimaryKeyType.STRING);
TableOptions options = new TableOptions();
options.setMaxVersions(1);
options.setTimeToLive(-1);
CreateTableRequest request = new CreateTableRequest(meta,options);
request.setReservedThroughput(new ReservedThroughput(new CapacityUnit(0, 0)));
CreateTableResponse response = client.createTable(request);
//创建多元索引并指定路由字段
CreateSearchIndexRequest searchIndexRequest = new CreateSearchIndexRequest();
searchIndexRequest.setTableName("order"); //订单表
searchIndexRequest.setIndexName("order_index"); //订单表索引名
IndexSchema indexSchema = new IndexSchema();
IndexSetting indexSetting = new IndexSetting();
indexSetting.setRoutingFields(Arrays.asList("user_id"));//设置商户id为路由字段
indexSchema.setIndexSetting(indexSetting);
//添加索引字段 这里只是给出示例,您可以根据业务需求添加索引字段
indexSchema.setFieldSchemas(Arrays.asList(
new FieldSchema("product_name",FieldType.KEYWORD).setStore(true).setIndex(true),
new FieldSchema("order_time",FieldType.LONG).setStore(true).setEnableSortAndAgg(true).setIndex(true),
new FieldSchema("user_id",FieldType.KEYWORD).setStore(true).setIndex(true)
));
searchIndexRequest.setIndexSchema(indexSchema);
client.createSearchIndex(searchIndexRequest);
Thread.sleep(6*1000); // 等待数据表加载
//插入一些测试数据
String[] productName = new String[]{"product a", "product b", "product c"};
String[] userId = new String[]{"00001", "00002", "00003", "00004", "00005"};
for (int i = 0; i < 100; i++){
PrimaryKeyBuilder primaryKeyBuilder = PrimaryKeyBuilder.createPrimaryKeyBuilder();
primaryKeyBuilder.addPrimaryKeyColumn("order_id",PrimaryKeyValue.fromString(i+""));
primaryKeyBuilder.addPrimaryKeyColumn("user_id",PrimaryKeyValue.fromString(userId[i%(userId.length)]));
PrimaryKey primaryKey = primaryKeyBuilder.build();
RowPutChange rowPutChange = new RowPutChange("order",primaryKey);
//写入属性列
rowPutChange.addColumn("product_name",ColumnValue.fromString(productName[i%(productName.length)]));
rowPutChange.addColumn("order_time",ColumnValue.fromLong(System.currentTimeMillis()));
rowPutChange.setCondition(new Condition(RowExistenceExpectation.IGNORE));
client.putRow(new PutRowRequest(rowPutChange));
}
Thread.sleep(20*1000);//等待数据同步到多元索引
//带上路由字段的查询
SearchRequest searchRequest = new SearchRequest();
searchRequest.setTableName("order");
searchRequest.setIndexName("order_index");
MatchQuery matchQuery = new MatchQuery();
matchQuery.setFieldName("user_id");
matchQuery.setText("00002");
SearchQuery searchQuery = new SearchQuery();
searchQuery.setQuery(matchQuery);
searchQuery.setGetTotalCount(true);
SearchRequest.ColumnsToGet columnsToGet = new SearchRequest.ColumnsToGet();
columnsToGet.setReturnAll(true);
searchRequest.setColumnsToGet(columnsToGet);
searchRequest.setSearchQuery(searchQuery);
PrimaryKeyBuilder pkbuild = PrimaryKeyBuilder.createPrimaryKeyBuilder();
pkbuild.addPrimaryKeyColumn("user_id",PrimaryKeyValue.fromString("00002"));
PrimaryKey routingValue = pkbuild.build();
searchRequest.setRoutingValues(Arrays.asList(routingValue));
SearchResponse searchResponse = client.search(searchRequest);
System.out.println(searchResponse.isAllSuccess());
System.out.println("totalCount:"+ searchResponse.getTotalCount());
System.out.println("RowCount:"+searchResponse.getRows().size());
}
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