首先执行以下代码， CREATE TABLE `t` ( `id` int NOT NULL, PRIMARY KEY (`id`) ); insert into t values (5), (10); -- session 1 start transaction; select * from t where id > 8 for share; -- session 2 start transaction; insert into t values (9);
此时， select * from performance_schema.data_locks 的输出为： +--------+---------------------------------------+-----------------------+-----------+----------+---------------+-------------+----------------+-------------------+------------+-----------------------+-----------+------------------------+-------------+------------------------+ | ENGINE | ENGINE_LOCK_ID | ENGINE_TRANSACTION_ID | THREAD_ID | EVENT_ID | OBJECT_SCHEMA | OBJECT_NAME | PARTITION_NAME | SUBPARTITION_NAME | INDEX_NAME | OBJECT_INSTANCE_BEGIN | LOCK_TYPE | LOCK_MODE | LOCK_STATUS | LOCK_DATA | +--------+---------------------------------------+-----------------------+-----------+----------+---------------+-------------+----------------+-------------------+------------+-----------------------+-----------+------------------------+-------------+------------------------+ | INNODB | 140043377180872:1063:140043381460688 | 2084 | 49 | 23 | test | t | NULL | NULL | NULL | 140043381460688 | TABLE | IX | GRANTED | NULL | | INNODB | 140043377180872:2:4:3:140043381458464 | 2084 | 49 | 25 | test | t | NULL | NULL | PRIMARY | 140043381458464 | RECORD | X,GAP,INSERT_INTENTION | WAITING | 10 | | INNODB | 140043377180024:1063:140043381454544 | 421518353890680 | 48 | 52 | test | t | NULL | NULL | NULL | 140043381454544 | TABLE | IS | GRANTED | NULL | | INNODB | 140043377180024:2:4:1:140043381451552 | 421518353890680 | 48 | 52 | test | t | NULL | NULL | PRIMARY | 140043381451552 | RECORD | S | GRANTED | supremum pseudo-record | | INNODB | 140043377180024:2:4:3:140043381451552 | 421518353890680 | 48 | 52 | test | t | NULL | NULL | PRIMARY | 140043381451552 | RECORD | S | GRANTED | 10 | +--------+---------------------------------------+-----------------------+-----------+----------+---------------+-------------+----------------+-------------------+------------+-----------------------+-----------+------------------------+-------------+------------------------+
X,GAP,INSERT_INTENTION 这个 LOCK_MODE 到底是什么呢？在文档没有找到相关的描述，Google 也没有搜索到相关内容。