Causes and solutions of lock table

First, the reasons for the lock table

1. The lock table occurs in insert update and delete;

2. The principle of locking the table is that the database uses an exclusive locking mechanism. When the above statement is executed, the table is locked until a commit or rollback occurs or the database user exits;

3. Reasons for locking the table:

1) When program A executes the insert to tableA and has not yet committed, program B also inserts tableA, then an exception that resources are busy will occur at this time, which is the lock table;

2), the lock table often occurs in concurrency rather than in parallel (in parallel, when one thread operates the database, another thread cannot operate the database, the principle of cpu and i/o allocation)

4. Reduce the probability of locking the table:
Reduce the time between the execution of the insert, update, and delete statements to the commite.
The specific point is that batch execution is changed to single execution, and the non-execution speed of sql itself is optimized.
If there is an abnormality, things will be rolled back.

Second, mysql lock table solution
#View the process id, then kill the process with kill id
show processlist;

SELECT * FROM information_schema.PROCESSLIST;

#Query the executing process
SELECT * FROM information_schema.PROCESSLIST where length(info) >0 ;

#Query whether to lock the table
show OPEN TABLES where In_use > 0;

#View locked
SELECT * FROM INFORMATION_SCHEMA.INNODB_LOCKS;

#Waiting for lock
SELECT * FROM INFORMATION_SCHEMA.INNODB_LOCK_WAITS;

#kill the lock table process
kill 5601

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