Mycat2 ER關(guān)系

CREATE TABLE db1. `travelrecord`(
 ?`id` bigint NOT NULL AUTO_INCREMENT,
 ?`user_id` varchar(100) DEFAULT NULL,
 ?`traveldate` date DEFAULT NULL,
 ?`fee` decimal(10,0) DEFAULT NULL,
 ?`days` int DEFAULT NULL,
 ?`blob` longblob,
 ?PRIMARY KEY (`id`),
 ?KEY `id` (`id`)
) ENGINE=InnoDB ?DEFAULT CHARSET=utf8 dbpartition by mod_hash(id) tbpartition by mod_hash(id) tbpartitions 2 dbpartitions 2;


CREATE TABLE db1.`travelrecord2` (
 ?`id` bigint NOT NULL AUTO_INCREMENT,
 ?`user_id` varchar(100) DEFAULT NULL,
 ?`traveldate` date DEFAULT NULL,
 ?`fee` decimal(10,0) DEFAULT NULL,
 ?`days` int DEFAULT NULL,
 ?`blob` longblob,
 ?PRIMARY KEY (`id`),
 ?KEY `id` (`id`)
) ENGINE=InnoDB ?DEFAULT CHARSET=utf8 dbpartition by mod_hash(user_id) tbpartition by mod_hash(user_id) tbpartitions 2 dbpartitions 2;

上述兩表具有相同的分片算法,但是分片字段不相同

mycat2在涉及這兩個(gè)表的join分片字段等價(jià)關(guān)系的時(shí)候可以完成join的下推

mycat2無需指定ER表,是自動(dòng)識(shí)別的,具體看分片算法的接口

查看配置的表是否具有ER關(guān)系,使用/*+ mycat:showErGroup{}*/查看

結(jié)果

groupId     schemaName  tableName
0           db1         travelrecord
0           db1         travelrecord2

group_id表示相同的組,該組中的表具有相同的存儲(chǔ)分布