介绍

:::tips AT模式中的快照生成、回滚等动作都是由框架自动完成，没有任何代码侵入，因此实现非常简单，但是使用AT模式需要准备两张表（一张表记录全局锁，一张表记录数据快照） :::

导入数据库表

:::tips 在Seata-TC服务关联的数据库中运行下面的SQL语句，创建记录全局锁的表（lock_table） :::

SET NAMES utf8mb4;
SET FOREIGN_KEY_CHECKS = 0;
-- ----------------------------
-- Table structure for lock_table
-- ----------------------------
DROP TABLE IF EXISTS `lock_table`;
CREATE TABLE `lock_table`  (
  `row_key` varchar(128) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NOT NULL,
  `xid` varchar(128) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NULL DEFAULT NULL,
  `transaction_id` bigint NULL DEFAULT NULL,
  `branch_id` bigint NOT NULL,
  `resource_id` varchar(256) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NULL DEFAULT NULL,
  `table_name` varchar(32) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NULL DEFAULT NULL,
  `pk` varchar(36) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NULL DEFAULT NULL,
  `gmt_create` datetime NULL DEFAULT NULL,
  `gmt_modified` datetime NULL DEFAULT NULL,
  PRIMARY KEY (`row_key`) USING BTREE,
  INDEX `idx_branch_id`(`branch_id` ASC) USING BTREE
) ENGINE = InnoDB CHARACTER SET = utf8mb4 COLLATE = utf8mb4_0900_ai_ci ROW_FORMAT = Dynamic;
SET FOREIGN_KEY_CHECKS = 1;

:::tips 在每个参与事务的微服务关联的数据库中运行下面的SQL语句，创建记录数据快照的表（undo_log） :::

SET NAMES utf8mb4;
SET FOREIGN_KEY_CHECKS = 0;
-- ----------------------------
-- Table structure for undo_log
-- ----------------------------
DROP TABLE IF EXISTS `undo_log`;
CREATE TABLE `undo_log`  (
  `branch_id` bigint NOT NULL COMMENT 'branch transaction id',
  `xid` varchar(128) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NOT NULL COMMENT 'global transaction id',
  `context` varchar(128) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NOT NULL COMMENT 'undo_log context,such as serialization',
  `rollback_info` longblob NOT NULL COMMENT 'rollback info',
  `log_status` int NOT NULL COMMENT '0:normal status,1:defense status',
  `log_created` datetime(6) NOT NULL COMMENT 'create datetime',
  `log_modified` datetime(6) NOT NULL COMMENT 'modify datetime',
  UNIQUE INDEX `ux_undo_log`(`xid` ASC, `branch_id` ASC) USING BTREE
) ENGINE = InnoDB CHARACTER SET = utf8mb4 COLLATE = utf8mb4_0900_ai_ci COMMENT = 'AT transaction mode undo table' ROW_FORMAT = Dynamic;
SET FOREIGN_KEY_CHECKS = 1;

添加配置

:::tips 在每个参与事务的微服务的配置文件中添加配置来开启AT模式 :::

seata:
    #默认就是AT模式，无需配置
    data-source-proxy-mode: AT