Category:Database

  • Distributed storage principle of sequoiadb

    Time:2020-12-1

    Distributed architecture is imperative In traditional database technology, in order to ensure data security and high performance, high-end external storage is usually selected as the main storage source of database, while local disk is regarded as an unreliable device with low performance. This concept is mainly due to the bottleneck of local disk production technology […]

  • Know yourself and know your enemy: persistent evolution

    Time:2020-12-1

    introduction When we talk about the word “persistence”, we must be familiar with the word “persistence”. In the process of persistence, there are two giants that attract the attention of developersHibernateAndMyBatisMany developers often compare the two. goGoogleOn, are similar to the two articles contrast each other. HibernateAndMyBatisIt’s likejavaandphpSimilarly, there seems to be a fight between […]

  • Detailed interpretation of distributed | dble release notes 2.19.09.0

    Time:2020-12-1

    The following is a detailed interpretation of the release notes of dble 2.19.09.0. The article is mainly divided into the following three parts: 1、 Introduction to dble project 2、 New version of the main update interpretation 3、 Complete release notes and Translation 1、 Introduction to dble project DBLE — Enterprise level open source distributed middlewareThe […]

  • MO_ On SQL optimization

    Time:2020-12-1

    1、 Introduction This paper is a review summary of SQL optimization. It mainly records how to use index to optimize SQL. The database is mysql. It is mainly discussed from three parts. Part one: understand the underlying data structure of MySQL index. The second part: explain in detail. The third part: MySQL index best practices. […]

  • On the analysis of think queue

    Time:2020-12-1

    preface Before analysis, please understand the implementation of message queue If you don’t know, please read the following: Design of liking message queue Design of qunar network message queue TP5 message queue is based on database redis and top think, which is officially implemented by TPThis chapter focuses on the analysis of redis Storage key: […]

  • Mongo randomly gets n pieces of data

    Time:2020-12-1

    Mongo command random sampling db.attachment_extract_status.aggregate( [ { $sample: { size: 500 }},{$match:{extract_status:1}} ] ) Mongotemplete random sampling @Test public void test_sample() { Aggregation aggregation = Aggregation.newAggregation( Aggregation.match(Criteria.where(“extract_status”).is(1)), Aggregation.sample(1000)); AggregationResults<JSONObject> outputTypeCount = mongoTemplate.aggregate(aggregation, “attachment_extract_status”, JSONObject.class); for (Iterator<JSONObject> iterator = outputTypeCount.iterator(); iterator.hasNext(); ) { System.out.println(iterator.next().getLong(“content_id”)); } }

  • Windows installation of MySQL multi version Master Slave replication

    Time:2020-12-1

    Install the following versions of MySQL under windows7:1、mysql-5.7.282. Mysql-8.0.20: main database3. Mysql-8.0.20: slave database 1、 Mysql-5.7.28 install and enable 1.1 download and install Installation free version:https://cdn.mysql.com/archives/mysql-5.7/mysql-5.7.28-winx64.zip Installation version:https://downloads.mysql.com/archives/community/ I use the installation free version and extract the file from the following path: F: mysqlmysql-5.7.28-winx64 1.2 configuration information First, create a new one under the path […]

  • [operation tutorial] sequoiadb distributed storage tutorial

    Time:2020-11-30

    1. Introduction to applicable scenarios of each mode becauseSequoiaDBCompared with other NoSQL, there are more ways to distribute data to multiple servers, so the author will introduce to readers which scenarios each distributed mode is suitable for. 1.1 hash distribution dataIn the hash distribution mode, because the hash value of a field in the collection […]

  • Write mybatis from scratch (3) JDBC pool realizes database connection pool from zero

    Time:2020-11-30

    Prospect review In the MVP version, we have implemented a basic running mybatis. Section 2 handwritten mybatis from scratch (2) detailed explanation of mybatis interceptor plug-in mechanism In this section, let’s take a look at how to implement a database connection pool. Why do I need connection pooling? The creation of database connection is a […]

  • Micro course lesson 2 Introduction to docker installation method

    Time:2020-11-30

    Micro course | lesson 2: introduction to docker installation methodhttps://v.youku.com/v_show/id… In the last issue, we introduced the basic overview of dble. Now we will go to the main topic. The main topic is basically divided into these four parts. The structure of the course catalogue 1. Installation demonstration We’ll introduce two ways to get started […]

  • MIT6.824-Lab2B

    Time:2020-11-30

    summary Lab2b needs us to improverf.Start(..)This function. This function takes acommandAs input parameter, if the current noderfyesleaderThen the process of reaching consensus will begin If the current node is a leader,rf.Start()The command will be pressed into its own log and the index will be returned immediately.The caller gets an index, which does not mean the […]

  • Alibaba cloud promotes six security solutions to escort financial institutions and promote online service

    Time:2020-11-30

    At the 2020 financial security summit held on March 24, Alibaba cloud launched six exclusive security solutions, including sensitive data protection and remote office security, to protect the basic security and business security of financial institutions. In recent years, financial institutions began to accelerate the cloud infrastructure, and accelerate the promotion of online financial services, […]