Programmer Think

brief introduction   I believe that the biggest motivation for many people to learn distributed locks is not their own system needs, but the needs of interviewers... Of course, this also shows that the distribution lock is very important. It is often used as an examination question. Before learning, we need to clarify several questions. ...

What is the purpose of redis distributed lock to solve? In order to solve the problem that synchronized can not achieve synchronization in distributed situations, because synchronized synchronization is the method of one jvm, which can not be done by multiple JVMs. 1. Implement the inventory reduction scenario of redis basic business Integer ...

Etcd distributed lock is not a function api provided by etcd server, but a tool for integrating various features (lease, watch, mvcc, etc.) based on etcd.In the same process, in order to avoid data competition for shared variables, it can usually be avoided by locking and unlocking. However, if multiple processes operate on the same resource, o ...

First knowledge of distributed lock (II): analysis of ZooKeeper distributed lock principle and practical cases It's not easy to write. Praise and collect attention so that you can see it next time. Thank you for your support ~ Last time we talked about using Mysql database to realize distributed locking. It is relatively simple to implem ...

Understanding of using distributed locks Each distributed lock has its advantages and disadvantages. In extreme cases, such as NPC, there may be wrong results and it is unsafe, as shown in the figure below (both clients think they have obtained the lock), NPC refers to Network Delay; Process Pause, Process Pause (GC) [such as JAVA GC]; Clock ...

Why do I need distributed locks In the concurrent scenario, it is necessary to use locks to mutually exclusive access to shared resources to ensure thread safety; Similarly, in the distributed scenario, a mechanism is also needed to ensure mutually exclusive access to multi node shared resources. The implementation mechanism is distributed loc ...

preface This article aims to share experience and welcome your comments Application scenario: 1. Second kill 2. Grab coupons 3. Interface idempotency check Summary: grab resources 1. Single lock -- > to distributed lock synchronized () is no longer described here 1.1. Based on opsforvalue() Setifabsent() implementation Format ...

preface Distributed locks are generally implemented in three ways: 1 Database lock; 2. Redis based distributed locks; 3. Distributed lock based on ZooKeeper. This blog will introduce the second way to implement distributed locks based on redis. Although there are various blogs on the Internet that introduce the implementation of redis distribu ...

Cache invalidation Cache penetration Content introduction Cache penetration refers to data that does not exist in the cache or database, but users constantly initiate requests, such as data with id of "- 1" or data with id of particularly large and nonexistent. At this time, the user is likely to be an attacker, and the attack ...

summaryProject address: https://github.com/snower/slockWhat is a state and atomic operations database? Unlike redis, which is mainly used to save data and can efficiently synchronize data between multiple nodes and systems, slock is designed to only save synchronization status and can hardly carry data. The high-performance asynchronous binary ...