• The difference between SRC and href


    When you write code, you often confuse these two attributes. Whether it’s a href or a SRC is a reference to hypertext,For elements such as link and aOn, the href is a reference and page Association, which establishes a relationship between the current element and the reference resource. The SRC is a reference resource, which […]

  • HTTP caching mechanism details


    Preface When requesting a static file (picture, CSS, JS), etc., the characteristics of these files are that the files do not change frequently. Storing these files that do not change frequently is a way to optimize the user’s browsing experience for the client. So this is the meaning of client cache. HTTP caching mechanism as […]

  • Please read the following sentence: introduction of resource estimator framework and algorithm analysis in resource manager


    Welcome to Tencent cloud + community to get more Tencent technology practice dry goods~ This article was published by Song Chao in cloud + community column This paper first introduces the framework and running process of the estimator service in the resource manager of Hadoop, and then analyzes the principle of the resource estimation algorithm […]

  • Browser kernel mechanism — will CSS loading cause blocking


    CSS loading will not block DOM tree parsing, but will block DOM tree rendering.So in order to avoid users seeing long white screen time, we should improve the loading speed of CSS as fast as possible.1. Use CDN;2. Compression of CSS (using packaging tools such as webpack and gulp);3. Reasonable use of cache (setting cache […]

  • Tomcat uses JNDI to configure data source


    1. Introduction to JNDI 1.1 definition JNDI is a set of interfaces for object naming and directory service proposed by sun. Its full name isJava Naming and Directory Interface, in short, JNDI abstracts a layer based on directory service to find Java objects. The definitions in Wikipedia are as follows: The Java Naming and Directory […]

  • Kubernetes garbage collector source code analysis (1)


    Kubernetes version: 1.13.2 background Because of the redis cluster created by the operator, the redis cluster is deleted abnormally (including the redis exporter statefullset and redis statefullset) after the kubernetes APIs server is restarted. After deletion, the operator rebuilds and reorganizes the cluster, and the instance IP changes (middleware containerization, we developed fixed IP, when […]

  • W: GPG error: http://repo.mysql.com trust inrelease in APT get update


    I. Problems in useapt-get updateThe following error occurred while updating package resources in Ubuntu environment: Ign http://repo.mysql.com trusty/mysql-tools Translation-en Fetched 3,164 B in 1min 42s (30 B/s) Reading package lists… Done W: GPG error: http://repo.mysql.com trusty InRelease: The following signatures were invalid: KEYEXPIRED 1487236823 KEYEXPIRED 1487236823 KEYEXPIRED 1487236823 From the error information, it can be […]

  • Starting from scratch k8s | k8s application arrangement and management


    1、 Resource meta information 1. Kubernetes resource object As we know, kubernetes’s resource object consists of two parts: spec and status. The spec part is used to describe the expected status, and the status part is used to describe the observed status. Today we will introduce another part of k8s, namely metadata part. This part […]

  • Why implement IDisposable interface?


    Background Recently, I found a problem in the intensive reading of CLR via C Chen and effective c Chen. Generally speaking, we achieveIDisposableInterface to release managed and unmanaged resources. However, there is a similar function in the definition of C ා type, which isFinalization device。 At the beginning, I studied C + +. Later, when […]

  • Testing Etag browser cache with curl request


    By NIC RaboyCrazy technology houseOriginal: https://www.thepolyglotdeveloNo reprint without permission Recently, I’ve been playing netlifly, and as a result, I’m getting more and more familiar with the caching strategies common to content delivery networks (CDNs). There is a policy to use Etag identifiers for web resources. In short, an Etag identifier is a value, usually a […]

  • Hadoop series (2) – cluster resource manager yarn


    1、 Introduction to Hadoop yarn Apache YARN(yet another resource negotiator) is a cluster resource management system introduced by Hadoop 2.0. Users can deploy various service frameworks on yarn to manage and allocate resources uniformly. <div align=”center”> <img width=”600px” https://raw.githubusercontent.com/heibaiying/BigData-Notes/master/pictures/yarn-base.png&quot” rel=”nofollow noreferrer”>https://raw.githubusercontent…;/> </div> 2、 Yarn architecture 1. ResourceManager ResourceManagerIt usually runs in the form of a […]

  • Flink slot details and job execution graph optimization


    Preface Recently, Flink job was migrated from standalone to onyarn, and then the performance of job was found to be lower than before: before migration, there was 8.3w + / s data consumption speed, after migration to yarn, the same resources were allocated, but the consumption speed was reduced to 7.8w + / s, and […]