idn locks

The pessimistic lock, as its name implies, is very pessimistic. Every time you get the data, you think someone else will modify it. So every time you get the data, you will lock it, in this way, others will block the data until it gets the lock. In traditional relational databases, many of these locks are used, such as row locks, table locks, read

Two File locks in Linux and two file locks in Linux A file lock is a file read/write mechanism that allows only one process to access one file at any specific time. Using this mechanism can make the process of reading and writing a single file more secure. In this article, we will explore different types of File locks in Linux and use the example program to under

Detailed description of pessimistic locks and optimistic locks in the database; Detailed description of the Database There are two types of locks in data: Pessimistic locks and optimistic locks, as well as table-level locks and r

Note: This article is reproduced from http://www.hollischuang.com/archives/923Row-level locks, table-level locks, page-level locks are described in MySQL, row-level locks are the most granular lock in MySQL, and row-level locks can significantly reduce database operation con

Note: This article is reproduced from http://www.hollischuang.com/archives/923Row-level locks, table-level locks, page-level locks are described in MySQL, row-level locks are the most granular lock in MySQL, and row-level locks can significantly reduce database operation con

Analysis of Inter-thread communication 2: read/write locks and spin locks, analysis of spin The mutex and condition variables are used for thread synchronization. This article discusses the use of read/write locks and spin locks, and provides the corresponding code and precautions, the relevant code can also be found i

OracleDatabasePessimistic lockAndOptimistic lockIs what we will introduce in this article. Sometimes, for maximum performance, databases generally have a concurrency mechanism, but the problem is Data Access conflicts. To solve this problem, most databases Use Data Locking. There are two methods to lock data: Pessimistic lock and optimistic lock. What is a pessimistic lock? A pessimistic lock, as its name implies, is a pessimistic attitude towards data conflicts. That is to say, assume that data

Implement distributed locks Based on Redis and distributed locks Based on Redis BackgroundIn many Internet product applications, some scenarios require locking, such as seckilling, global incremental ID, and floor generation. Most solutions are implemented based on databases. Redis adopts the single-process and single-thread mode and uses the queue mode to convert concurrent access to serial access. In addi

Lightweight locks The JDK1.6 appeared. It is not a substitute for a heavyweight lock, which is meant to reduce the performance consumption of traditional heavyweight locks using operating system mutexes without multiple threading competition. Hotspot the Run-time data of the virtual machine Object Header object itself such as: hash (hashcode), GC generational age (generational GC), this part of the data in

Application scenarios and scenarios of optimistic locks and pessimistic locks Locking)During the implementation of business logic, data access needs to be exclusive. For example, end computing on the day of the Financial SystemProcessing, we want to process the data at a cut-off time point, rather than in the settlement process.(Several seconds or several hours), and the data changes again. In this case, w

Lock(Locking)During the implementation of business logic, data access needs to be exclusive. For example, in the daily final computing process of the financial system, we want to process the data at a cut-off time point instead of the settlement process (which may be several seconds, or several hours), and the data changes again. At this point, we need to use some mechanisms to ensure that the data will not be modified by the outside world during an operation. This mechanism is called a "Lock" h

lock is used. Multiple locks can be directly processed in parallel based on different imported keys, similar to the row-level locks of Innodb. Use: $ Lock = new CacheLock ('key _ name '); $ Lock-> lock (); // Logic here $ Lock-> unlock (); // Note that the write permission is required for the path of the file lock. The specific classes are as follows: The code is as follows: /** * CacheLock process loc