Taking InnoDB of MySQL as an example, the preset Tansaction isolation level is repeatable read, and the READ locks in SELECT are mainly divided into two methods:SELECT... lock in share mode select... FOR UPDATEThese two methods will be executed only
Select for Update/lock in share mode affects transactional concurrencyconcurrency understanding of transactionsTransactional concurrency, a cursory understanding of the number of transactions that can be performed per unit of time, is a common unit
MySQL常用指令，java，php程序员，数据库工程师必备。程序员小冰常用资料整理MySQL common commands (for reference)The most common display commands are:1. Display the list of databases.show databases;2. Display the data table in the library:Use MySQL;Show tables;3, display the
Select ... The syntax for the FOR UPDATE statement is the same as the SELECT statement, except that the for UPDATE [NOWAIT] clause is appended to the SELECT statement.The statement is used to lock a specific row, if there is a WHERE clause, which
Recent projects, as it relates to the use of optimistic and pessimistic locks in MySQL data, summarize the knowledge of optimistic and pessimistic locks in conjunction with project and online knowledge points.Pessimistic Lock IntroductionPessimistic
1. Full backup and incremental backup 1.1 full-scale backupFull-volume data is all the data in the database, and a full backup is the backup of all the data in the database.Back Up all libraries:mysqldump -uroot -p123456 -S /data/3306/mysql.sock -F -
With MySQL InnoDB as an example, the preset tansaction isolation level is repeatable read and the read lock in select is divided into two main ways:SELECT ... LOCK in SHARE MODE SELECT ... For UPDATEBoth of these methods must wait for the other
Pessimistic locking, as its name implies, is a conservative attitude to the data being modified by the outside world (including other transactions currently in the system, as well as transactions from external systems), so that the data is locked
Mysql select for update MySQL use SELECT... for update confirmation before transaction writing take MySQL's InnoDB as an example. The preset Tansaction isolation level is repeatable read, and the select read lock can be divided into two methods: www.
In the case of MySQL InnoDB, the preset tansaction isolation level is repeatable read, and there are two main ways to read locks in a select:
SELECT ... LOCK in SHARE MODE SELECT ... For UPDATE
Both of these methods must wait for the other
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