Mysql get lock information

The tables that contain information about InnoDB transactions and data locks enable you to. This section describes functions used to manipulate user-level locks. GET_LOCK(), Get a named lock. This will show you a list of all current processes, their SQL query and state. Also see this link for more information on using the innotop tool.

The status text will show transaction information on the transactions that deadlocke which locks they hel and which they were waiting for. Look at the sections titled “WAITING FOR THIS LOCK TO BE GRANTED” and “HOLDS THE LOCKS. In its simplest form is displays all locked tables.

When the first lock is taken, the value increments to 1. SHOW PROCESSLIST statement to show detailed information :. The locked data is reserved for read by the current session. Other transaction can read this rows only once first transaction get commit or . It has different sections of information among which you can find the information on latest . However, when you query the locks information , the blocking query is. Now application A needs to get a lock on table row in order to continue the.

Suppose we have a test database with information from the . Usually it was not that easy to deal with the output of SHOW ENGINE . When you try to get the table-level write lock on the table ( lock table tab_name write). What does that mean and how to proceed from that to . X lock on parent row 1. I then get a nice overview, with already-taken seats in grey, the free ones. Open a database session and acquire an exclusive lock on a data row as shown in listing 05. SLEEP thread causing Waiting for table metadata lock. FOR UPDATE statement for each rows expected to be . Note that for a new inserted row, the lock information is carried by the transaction ID.

SELECT , INSERT, DELETE, and UPDATE . For more information about how deadlocks are automatically detected and . SHARE lock on the table that prevents concurrent data. Debugging transactional and locking issue in a database can be tricky business. Select ID from information_schema. SHOW VARIABLES LIKE performance_schema;.

Locking information can be accessed through metadata_locks table. There will be a lot of info , but near the end you should find the process. If you need more details about mysql locks , you can find them in here:. MySQL thread id OS thread . InnoDB data structures related to locks and transactions Data.

When a lock is applie the data cannot be modified except by the query that initiated the lock. For additional information about the interaction between table locking and . A lock wait timeout when one user gets a lock on some data while another tries to access it. I would like to know how to lock and unlock entire mysql database.

Find all InnoDB transactions in the Running status by running the following command:.