Lock wait timeout exceeded; try restarting transaction

1. How do I fix Lock wait timeout exceeded try restarting transaction?
2. What Causes Lock wait timeout?
3. What is MySQL Lock wait timeout?
4. How do I know if a table is locked in MySQL?
5. How do you increase lock timeout?
6. How does InnoDB check engine status?
7. What is lock timeout?
8. What is the difference between a lock and a deadlock?
9. What is lock wait?
10. What is deadlocks and timeout?
11. How do I unlock a locked table in MySQL?
12. What is mutex lock in MySQL?

How do I fix Lock wait timeout exceeded try restarting transaction?

MySql Lock wait timeout exceeded; try restarting transaction

1. Enter MySQL. mysql -u your_user -p.
2. Let's see the list of locked tables. mysql> show open tables where in_use>0;
3. Let's see the list of the current processes, one of them is locking your table(s) mysql> show processlist;
4. Kill one of these processes.

What Causes Lock wait timeout?

A lock wait timeout results when one user gets a lock on some data and holds it while another user tries to access it. If the first user doesn't unlock the data, the second one will time out after a while. The database will respond to the second user with an error message saying their lock wait was too long.

What is MySQL Lock wait timeout?

A lock wait timeout causes InnoDB to roll back the current statement (the statement that was waiting for the lock and encountered the timeout). To have the entire transaction roll back, start the server with --innodb-rollback-on-timeout enabled.

How do I know if a table is locked in MySQL?

SHOW OPEN TABLES to show each table status and its lock. SHOW OPEN TABLES WHERE `Table` LIKE '%[TABLE_NAME]%' AND `Database` LIKE '[DBNAME]' AND In_use > 0; to check any locked tables in a database. You can use SHOW OPEN TABLES to show each table's lock status.

How do you increase lock timeout?

To increase the lock wait timeout:

1. SSH into the control server as the root user.
2. Edit the file /etc/my.cnf : ...
3. Verify no transactions are running/pending and stop the OnApp daemon with /etc/init.d/onapp stop.
4. Restart the MySQL server with /etc/init.d/mysqld restart.

How does InnoDB check engine status?

SHOW ENGINE INNODB STATUS is a specific form of the SHOW ENGINE statement that displays the InnoDB Monitor output, which is extensive InnoDB information which can be useful in diagnosing problems.

What is lock timeout?

A lock timeout occurs when a transaction, waiting for a resource lock, waits long enough to have surpassed the wait time value specified by the locktimeout database configuration parameter. This consumes time which causes a slow down in SQL query performance.

What is the difference between a lock and a deadlock?

On one side of the lock is a keyhole and on the other is another keyhole and turnable knob. When in deadlock mode the knob is inoperable. ... When not in the deadlock mode you are able to use the handle to unlock and open the door from the inside.

What is lock wait?

A lock wait occurs when a transaction tries to obtain a lock on a resource that is already held by another transaction. When the duration of the lock wait time is extended, this results in a slow down of SQL query execution.

What is deadlocks and timeout?

The timeout period refers to the length of time a transaction waits to acquire a lock before it gives up. A deadlock occurs when two or more transactions are waiting for each other in a cyclic fashion.

How do I unlock a locked table in MySQL?

Another use for UNLOCK TABLES is to release the global read lock acquired with the FLUSH TABLES WITH READ LOCK statement, which enables you to lock all tables in all databases.

What is mutex lock in MySQL?

Mutexes are mutually exclusive locks and are designed to prevent concurrent access to resources that in doing so may result in unsafe conditions. They are required as part of virtually all multi-threaded applications (not just MySQL), and are not something that you can specifically prevent from happening.