The article contains information about LOCK TABLES in MySQL VTY system.<\/p>\n
Features added to the database during database design or later (INDEX, Foreign Key, UNIQUE …) can provide performance improvements.<\/p>\n
As the database size increases, the added features cause the basic functions like SELECT, INSERT, UPDATE, DELETE to slow down.<\/p>\n
Because when every record is added; As an extra, operations such as adding records to the index, renewing the INDEX map, UNIQUE control are performed.<\/p>\n
Also, performing similar operations performed by more than one session causes MySQL VTY system to slow down.<\/p>\n
Thanks to the LOCK TABLES feature in MySQL, the table queues requests from other sessions for a period of time for a transaction, and transactions are made faster.<\/p>\n
The following statement is used to lock the table.<\/p>\n
LOCK TABLES table_name READ|WRITE;<\/pre>\nREAD:<\/strong> It is not possible to add, delete or update records in the table requested by other sessions. They can only read the data.<\/p>\n
WRITE:<\/strong> Blocks all requests requested by other sessions.<\/p>\n
While adding sa record to a table, let’s lock the table.<\/p>\n
In order to observe the table locking process, two different logins are required from the operating system command interpreter, or two different MySQL tools must be used.<\/p>\n
First, let’s lock the table with the following expression from a session.<\/p>\n
LOCK TABLES MyTable WRITE;<\/pre>\nWhen the following command is executed in the session where the table is locked, detailed information can be seen about the operation waiting to be unlocked.<\/p>\n
SELECT * FROM MyTable;<\/pre>\nUNLOCK TABLES in MySQL<\/h3>\n
To unlock the table, it will be enough to run the command below or close the session.<\/p>\n
UNLOCK TABLES;<\/pre>\nCheck LOCKED TABLES in MySQL(locked by LOCK TABLE)<\/h3>\n
You can use the below command to check locked tables which locked by LOCK TABLE. IN_USE column indicates that the table is locked.<\/p>\n
show open tables;<\/pre>\nor better;<\/p>\n
show open tables where in_use > 1;<\/pre>\nor if you want to see locked tables only for a\u00a0 specific database;<\/p>\n
show open tables in mydatabase;<\/pre>\n<\/div>\n