What does mysql intermittent lock mean?

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Description

1. Gap lock is a lock mechanism introduced by Innodb to solve the problem of phantom reading under submission.

2. For records whose key values are within the range of conditions but do not exist, a request for a record that does not exist under equal conditions will also be locked, which is called a gap lock.

Example

# session1 operation session session1 opens transaction mysql > begin; Query OK, and 0 rows affected (0.00 sec) # session1 updates the data of id=11 to acquire row locks. Mysql > select * from userinfo where id=11 for update; Empty set (0.00 sec) # session2 operation session session2 opens transaction mysql > begin; Query OK, 0 rows affected (0.00 sec) # session2 adds data primary key 12 mysql > insert into userinfo values in session session2; Has been blocked # if the waiting time is too long and session1 does not release the lock, the following exception will be thrown. ERROR 1205 (HY000): Lock wait timeout exceeded; try restarting transaction thank you for reading, the above is the content of "what does mysql intermittent lock refer to". After the study of this article, I believe you have a deeper understanding of what mysql intermittent lock refers to, and the specific use needs to be verified in practice. Here is, the editor will push for you more related knowledge points of the article, welcome to follow!