382 Order‐by Merger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 382 Group‐by Merger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 384 Aggregation Merger try to reduce the influence of sharding, in order to let users use horizontal sharding database group like one database. 3.1.4 Application Scenarios Mass data high concurrency in OLTP scenarios Most select_expr [, select_expr ...] FROM table_reference [, table_reference ...] [WHERE predicates] [GROUP BY {col_name | position} [ASC | DESC], ...] [ORDER BY {col_name | position} [ASC | DESC], ...] [LIMIT

409 Order‐by Merger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 409 Group‐by Merger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 411 Aggregation Merger try to reduce the influence of sharding, in order to let users use horizontal sharding database group like one database. 3.1.4 Application Scenarios Mass data high concurrency in OLTP scenarios Most select_expr [, select_expr ...] FROM table_reference [, table_reference ...] [WHERE predicates] [GROUP BY {col_name | position} [ASC | DESC], ...] [ORDER BY {col_name | position} [ASC | DESC], ...] [LIMIT

550 Order‐by Merger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 550 Group‐by Merger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 552 Aggregation Merger try to reduce the influence of sharding, in order to let users use horizontal sharding database group like one database. 8.1.4 Application Scenarios Mass data high concurrency in OLTP scenarios Most select_expr [, select_expr ...] FROM table_reference [, table_reference ...] [WHERE predicates] [GROUP BY {col_name | position} [ASC | DESC], ...] [ORDER BY {col_name | position} [ASC | DESC], ...] [LIMIT

521 Order‐by Merger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 521 Group‐by Merger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 523 Aggregation Merger try to reduce the influence of sharding, in order to let users use horizontal sharding database group like one database. 8.1.4 Application Scenarios Mass data high concurrency in OLTP scenarios Most select_expr [, select_expr ...] FROM table_reference [, table_reference ...] [WHERE predicates] [GROUP BY {col_name | position} [ASC | DESC], ...] [ORDER BY {col_name | position} [ASC | DESC], ...] [LIMIT

select_expr [, select_expr ...] FROM table_reference [, table_reference ...] [WHERE predicates] [GROUP BY {col_name | position} [ASC | DESC], ...] [ORDER BY {col_name | position} [ASC | DESC], ...] [LIMIT 9. 影子库 46 Apache ShardingSphere document 基于列的影子算法 SQL 不支持列表：* 不支持 DDL * 不支持范围、分组和子查询，如：BETWEEN、GROUP BY ⋯HAVING 等 SQL 支持列表：‐ INSERT SQL 是否支持 INSERT INTO table (column,⋯) VALUES (value,⋯) 支持 INSERT seata.tx.timeout，全局事务超时（秒），存在默认值为 60 3. client.application.id，应用唯一主键 4. client.transaction.service.group，所属事务组，存在默认值为 default 一个完全配置的 seata.conf 如下， shardingsphere.transaction.seata.at.enable = true shardingsphere

Database . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 Primary Replica Replication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 Load Balance Strategy . . . . . 278 Order‐by Merger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 278 Group‐by Merger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 280 Aggregation Merger t_order CHECK TABLE t_order SET RESOURCE GROUP group_name DROP RESOURCE GROUP group_name CREATE RESOURCE GROUP group_name TYPE = SYSTEM ALTER RESOURCE GROUP rg1 VCPU = 0‐63 Source Codes: https://github

select_expr [, select_expr ...] FROM table_reference [, table_reference ...] [WHERE predicates] [GROUP BY {col_name | position} [ASC | DESC], ...] [ORDER BY {col_name | position} [ASC | DESC], ...] [LIMIT document, v5.2.0 3.9.7 使用限制 基于 Hint 的影子算法 • 无。 基于列的影子算法 • 不支持 DDL； • 不支持范围、分组和子查询，如：BETWEEN、GROUP BY ⋯HAVING 等。SQL 支持列表： – INSERT SQL 是 否 支 持 INSERT INTO table (column,⋯) VALUES (value,⋯) 支持 BETWEEN SELECT/UPDATE/DELETE ⋯WHERE column BETWEEN value1 AND value2 不 支 持 GROUP BY ⋯ HAVING⋯ SELECT/UPDATE/DELETE ⋯WHERE ⋯GROUP BY column HAV‐ ING column > value 不 支 持 子查询 SELECT/UPDATE/DELETE ⋯WHERE

Database . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 Primary Replica Replication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 Load Balance Strategy . . . . . 267 Order‐by Merger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 267 Group‐by Merger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269 Aggregation Merger t_order CHECK TABLE t_order SET RESOURCE GROUP group_name DROP RESOURCE GROUP group_name CREATE RESOURCE GROUP group_name TYPE = SYSTEM ALTER RESOURCE GROUP rg1 VCPU = 0‐63 openGauss The unsupported

Database . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68 Primary Replica Replication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68 Load Balance Strategy . . . . . name after sharding, or misconducts caused by operations such as pagination, order by or aggregated group by are just the case in point. 3.1. Sharding 10 Apache ShardingSphere document, v5.0.0-beta Cross‐database information, sharding conditions, auto‐increment primary key information, Order By information, Group By information, and pagination information (Limit, Rownum and Top). One‐ time SQL parsing process

select_expr [, select_expr ...] FROM table_reference [, table_reference ...] [WHERE predicates] [GROUP BY {col_name | position} [ASC | DESC], ...] [ORDER BY {col_name | position} [ASC | DESC], ...] [LIMIT • 无。 8.9. 影子库 46 Apache ShardingSphere document 基于列的影子算法 • 不支持 DDL； • 不支持范围、分组和子查询，如：BETWEEN、GROUP BY ⋯HAVING 等。SQL 支持列表： – INSERT SQL 是 否 支 持 INSERT INTO table (column,⋯) VALUES (value,⋯) 支持 classpath 中增加 seata.conf 文件。 client { application.id = example ## 应用唯一主键 transaction.service.group = my_test_tx_group ## 所属事务组 } 根据实际场景修改 Seata 的 file.conf 和 registry.conf 文件。 9.1.4 可选插件 ShardingSphere