【 TiDB 使用环境】线上、测试、调研
【 TiDB 版本】
【遇到的问题】
当前环境是悲观事务模式，为什么我下面的测试中，session2的事务提交了以后，session1的事务再提交会出现写写冲突的信息呢?
mysql>
mysql> show variables like '%txn_mode%';
+---------------+-------------+
| Variable_name | Value |
+---------------+-------------+
| tidb_txn_mode | PESSIMISTIC |
+---------------+-------------+
1 row in set (0.01 sec)
mysql> show create table zjp;
+-------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table | Create Table |
+-------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| zjp | CREATE TABLE `zjp` (
`id` int(11) NOT NULL,
`name` varchar(10) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin |
+-------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)
SESSION1: 开启事务
mysql>
mysql> begin;
Query OK, 0 rows affected (0.00 sec)
SESSION2:更新id=13的记录
mysql> begin;
Query OK, 0 rows affected (0.00 sec)
mysql> update zjp set name=‘ABC’ where id=13;
Query OK, 1 row affected (0.00 sec)
Rows matched: 1 Changed: 1 Warnings: 0
mysql> commit;
Query OK, 0 rows affected (0.00 sec)
SESSION1:更新id=13的记录，后台日志报写冲突
mysql> update zjp set name=‘ABC’ where id=13;
Query OK, 1 row affected (0.05 sec)
Rows matched: 1 Changed: 1 Warnings: 0
tidb.log
[2022/08/09 10:57:24.191 +08:00] [INFO] [adapter.go:633] [“pessimistic write conflict, retry statement”] [conn=446] [txn=435162658714681346] [forUpdateTS=435162658714681346] [err=“[kv:9007]Write conflict, txnStartTS=435162658714681346, conflictStartTS=435162659501113346, conflictCommitTS=435162668178079745, key={tableID=534, handle=12} primary={tableID=534, handle=12} [try again later]”]
【复现路径】做过哪些操作出现的问题
【问题现象及影响】
【附件】
请提供各个组件的 version 信息，如 cdc/tikv，可通过执行 cdc version/tikv-server --version 获取。
