• 7.3 service creation, maintenance and horizontal expansion


    Create a service In swarm mode, docker run is basically not used #Swarm manager node docker service create –name busybox busybox /bin/sh -c “while true;do sleep 3600;done” View the service list [[email protected] ~]$ docker service ls ID NAME MODE REPLICAS IMAGE PORTS 426kwqf7gxif busybox replicated 1/1 busybox:latest Replicated indicates that this service can scale horizontally […]

  • Summer self-study day 14 | database (VII) – affairs


    Series articles: Summer self-study day 09 | database (I) – SQL, DDL Summer self-study day 10 | database (II) – DML Summer self-study day 10 | database (III) – DQL Summer self-study day 11 | database (IV) – constraints Summer self-study day 12 | database (V) – multi table, database design Summer self-study day 13 […]

  • 🍖 Transaction isolation mechanism


    1、 Introduction to transaction isolation mechanism Transaction hasAtomicity, consistency, isolation, persistenceFour characteristics andIsolationAs the name suggests, transactions are isolated from each other. When multiple transactions process a data at the same time, they do not affect each other. If the isolation is not good enough, there may be problemsDirty reading, unrepeatable reading, phantom reading, etcphenomenon […]

  • Database transaction acid attribute, database concurrency problem and four isolation levels


    Database transaction acid attribute, database concurrency problem and four isolation levels Database transaction A database transaction is a set of logical operation units that transform data from one state to another A set of logical operation units; One or more DML operations Transaction processing principles Ensure that all transactions are executed as a unit of […]

  • [Aurora notes] new features of IOS 15 push


    prefaceAt 1 a.m. Beijing time on June 8, 2021, apple held WWDC 21 conference. A new version of IOS 15 system was released at the meeting. The theme of IOS is focus, connect, and explore. Students who are concerned about this topic should find that the focus mentioned in this topic is the new change […]

  • Review of key points of PHP middle and senior interview yesterday


    Due to the epidemic situation, there is a video interview, one HR supervisor and one product manager of Party A,The direct person in charge of this interview is technical director a, and the other two seem to be heads of different departments in the same position (B and C) (well, they are both 35 +). […]

  • Spring transaction summary


    1. What is a transaction? A transaction is a logical set of operations that are either executed or not executed. Each business method of our system may include multiple atomic database operations, such as the following  savePerson()  Method has two atomic database operations. These atomic database operations are dependent, and they are either executed or […]

  • 【mmwave】DeviceSurvey


    From: http://liudongdong1.github.io/ Millimeter wave (mmWave) is a special class of radar technology that uses shortwavelength electromagnetic waves. Radar systems transmit electromagnetic wave signals that objects in their path then reflect. By capturing the reflected signal, a radar system can determine the range, velocity and angle of the objects. operating at 76–81 GHz (with a corresponding […]

  • 4. MySQL — transaction isolation


    2. Isolation level of transactions Transaction isolation is that when multiple users access the database concurrently, the transactions opened by the database for each user cannot be disturbed by the operations of other transactions, and multiple transactions should be isolated from each other\Some problems are easy to occur in concurrent transactions: Loss of data update: […]

  • In the process of looking at the spring source code, is there a source file such as package-info.java? What is it for?


    When reading the spring framework source code, do you still have the impression that there will be a package-info.java file under each package? If you don’t remember, you can take another look and open it to see what’s inside. So what is this file for? Let’s talk briefly! WeChat search official account No.“The legend of […]

  • Apache pulsar September report: pulsar summit Asia station officially launched


    A quick look this month Product dynamics New features Bug repair Community dynamics Community dynamics at home and abroad Technical dry goods About Apache pulsar Apache pulsar is a top-level project of Apache Software Foundation. It is a native distributed message flow platform for the next generation cloud. It integrates message, storage and lightweight functional […]