drm lock

Today, the flush tables with read lock command was used to solve Database Synchronization exceptions, so I learned about the lock table by the way. 1. FLUSH TABLES WITH READ LOCK This command is global read lock. After the command is executed, all tables in all databases are locked and read-only. It is generally used f

ObjectiveAbout eating hot pot scenes, small partners are not unfamiliar, eat hot pot when a classmate to the pot under the fish pill, b students at the same time to eat fish pills, it may lead to eat raw fish pills.In order to avoid this situation, in the process of the next fish pill, the first lock operation, so that the small pot-eating partners to stop for a while, and so on before the fish pill cooked and then open to eat, then python how to simu

Today, I saw the interesting question: what is the difference between locking and non-static methods on static methods, so that some understanding of the lock mechanism is introduced again.First look at the method:This is a very simple class that shares static variable num, and then a static and non-static method, all with a lockWe assume that there are two threads that operate both methods simultaneously, so can data be mutually exclusive?Java code

Llinxu Mandatory lock default is not open, want to let Linux support mandatory lock, not only when the mount is required to add-o mand, andThe files you want to lock are also required to set permissions.1. The proposed lock industry is called a cooperative lock, for this typ

As we all know, the disadvantage of multithreading is that the code will be the interference of concurrent access, the solution is the synchronization mechanism. The two common forms of synchronization are synchronous code blocks and synchronization functions, and both forms of locks are implicitly locked, and the former holds a lock that is the default. Starting with the JDK1.5, the lock is encapsulated by

Recently, because of the need in the work, learning the optimistic lock and pessimistic lock related knowledge, here I pass this article, I myself to these two "lock home" brother understanding record down; -Pessimistic lock: As its name implies, it refers to the conservative attitude of the data being modified by the

Pessimistic lock and optimistic lock are two common methods of resource concurrent lock design, and also a very basic concept in concurrent programming. In this paper, the two common locking mechanisms in the database data on the implementation of the system is introduced.Pessimistic lock (Pessimistic

Label: DDL statements only request table locks at the intent level. In the lock table statement, MySQL will request a MySQL level table lock, and InnoDB will also request a INNODB level table lock. The premise is Innodb_table_locks=1. https://www.percona.com/blog/2012/07/31/innodb-table-locks/ MySQL table level Locks and Innodb table levellocks is separate being

Oracle lock table troubleshooting example: Oracle lock table troubleshooting One time a developer directly runs the delete table operating system on the database server during peak hours, resulting in no response for a long period of execution. Then, the SQLPLUS client is closed and the delete statement is run again, this causes the database to run slowly.The query operation knows that it is caused by the

Relationship between innodb table level lock and lock table statement, innodbtable DDL statements only apply for intention-Level Table locks. In the lock table statement, mysql applies for mysql-Level table locks, and innodb also applies for innodb-Level table locks. The premise is that innodb_table_locks = 1 Https://www.percona.com/blog/2012/07/31/innodb-table

I recently read Java Concurrent in Practice (java Concurrent programming Practice) and found that I have a superficial understanding of java threads, locks, and other mechanisms, and I have not learned fully enough. I plan to use this book to comprehensively learn about the concurrent development of JDK and some thread-related theoretical knowledge, and fill in my own gaps. I can also communicate with you and understand what is incorrect, thank you for your correction. In the first blog, I will

I. Definition of database transactionsSecond, the database transaction concurrency may bring problemsThird, database transaction isolation LEVELIv. Setting the database isolation level with HibernateV. Using pessimistic locks to resolve transaction concurrency problemsVi. using optimistic locking to resolve transaction concurrency problemsHibernate transaction and concurrency problem processing (optimistic lock and pessimistic

Various Mac lock methods and Mac lock Methods I used Windows to get used to the Windows + L shortcut key lock screen. When I leave my computer, I can easily lock the machine to avoid being spoofed. The most important thing is a safe habit. but one of the major problems I encountered after changing my MacBook was that I

in this example, the begin Tran and with (holdlock) hints are used to observe the locks of SQL Server in the SELECT statement. The transaction is turned on to ensure that the lock is also observed by a very short query, because HOLDLOCK releases the lock after the transaction ends. 1. Query the SELECT statement for the primary key indexThe lock case is:Here I sel

Tags: style class blog Code HTTP EXTIn order to protect the data dictionary metadata, MySQL uses the metadata lock, the MDL Lock, to ensure the consistency of the structural changes in the case of concurrency.The addition of the MDL Lock mode and the source of the organization and the previous blog in the MySQL table lock