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2025-03-18 Update From: SLTechnology News&Howtos shulou NAV: SLTechnology News&Howtos > Database >
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This article focuses on "how to use innodb row locks". Interested friends may wish to have a look. The method introduced in this paper is simple, fast and practical. Let's let the editor take you to learn how to use innodb line locks.
Three levels
Record lock locks a row of records
Gap lock locks records in a certain range
Next key lock is the superposition of the first two effects.
Experimental environment
Mysql > select @ @ tx_isolation
+-+
| | @ @ tx_isolation |
+-+
| | REPEATABLE-READ |
+-+
1 row in set (0.00 sec)
Mysql > select * from t
+-+
| | id |
+-+
| | 2 |
| | 8 |
| | 19 |
| | 22 |
+-+
Mysql > create index t_ind on t (id)
Query OK, 0 rows affected (8.52 sec)
Open two sessions at the same time and open things
Conversation one
Mysql > start transaction
Query OK, 0 rows affected (0.00 sec)
Mysql > delete from t where id=19
Query OK, 1 row affected (0.00 sec)
Conversation two
Mysql > start transaction
Query OK, 0 rows affected (0.00 sec)
Mysql > insert into t values (55)
Query OK, 1 row affected (0.00 sec)
Mysql > insert into t values (10)
^ C ^ C-- query aborted
ERROR 1317 (70100): Query execution was interrupted
Mysql >
Mysql > insert into t values (1)
Query OK, 1 row affected (0.00 sec)
Mysql > insert into t values (12)
^ C ^ C-- query aborted
ERROR 1317 (70100): Query execution was interrupted
Mysql >
Session 2 indicates that between 8-22 is locked and data cannot be inserted. This is gap lock.
Cancel gap lock
Modify the isolation level of things to READ COMMITTED
At this point, I believe you have a deeper understanding of "how to use innodb row locks". You might as well do it in practice. Here is the website, more related content can enter the relevant channels to inquire, follow us, continue to learn!
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