MySQL Lock implementation

§1. InnoDB row locks are implemented by locking the index entries on the index, unlike Oracle, which is implemented by locking the corresponding data rows in the data block.

InnoDB This type of row lock implementation is characterized by the fact that InnoDB uses row-level locks only if the data is retrieved by index criteria, otherwise INNODB will use a table lock!

§2. Since the MySQL row lock is for the index plus lock, not for the record plus the lock, so although it is access to the record, but if you use the same index key, there will be a lock conflict. Be aware of this when applying design.