Category:DBT

  • (Do not request a bean from a BeanFactory in a destroy method implementation!)

    Time:2022-5-26

    Exception: Singleton bean creation not allowed while singletons of this factory are in destruction (do not request a bean from a beanfactory in a destruction method implementation!) If your project references spring cloud starter Zipkin jar and spring boot starter data redis jar at the same time, redis will not be connected and this exception […]

  • Redis Client On Error: Error: write ECONNABORTED Config right

    Time:2022-5-26

    Solve the redis client on error: error: write econnaborted config rightwe Problem Description: Solution: 1. First, check whether the firewall of Linux is turned on Turn off the firewall [[email protected]]# systemctl stop firewalld.service Open 6379 port number [[email protected]]# sudo firewall-cmd –zone=public –add-port=6379/tcp –permanent success [[email protected]]# sudo firewall-cmd –reload success 2. Check whether the redis startup […]

  • Springboot 2.6.3 integrated redis stepped on the pit

    Time:2022-5-26

    The integration steps are as follows: development tools: idea2019, JDK1.8, maven 3.5.4 Idea creates a new project, selects spring initializer, selects spring boot version 2.6.3 (the latest version at present), and adds web, and redis modules. After successful construction, the POM file is as follows: <?xml version=”1.0″ encoding=”UTF-8″?> <project xmlns=”http://maven.apache.org/POM/4.0.0″ xmlns:xsi=”http://www.w3.org/2001/XMLSchema-instance” xsi:schemaLocation=”http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd”> <modelVersion>4.0.0</modelVersion> <parent> […]

  • [go] several modification points of supporting Emoji characters in MySQL

    Time:2022-5-26

    To enable the MySQL table to support the storage of emoticon characters, you need to pay attention to the following character encoding processing:   The database code can be utf8mb4 The encoding of the table is utf8mb4 The content field in the table is utf8mb4   Connection to database is utf8mb4 For example, go connects […]

  • Summary of two methods of calculating the distance between two points by PostgreSQL

    Time:2022-5-26

    PostgreSQL calculates the distance between two points There are two methods: select ST_Distance( ST_SetSRID(ST_MakePoint(115.97166453999147,28.716493914230423),4326)::geography, ST_SetSRID(ST_MakePoint(106.00231199774656,29.719258550486572),4326)::geography ), ST_Length( ST_MakeLine( ST_MakePoint(115.97166453999147,28.716493914230423), ST_MakePoint(106.00231199774656,29.719258550486572) )::geography ) remarks: ST_ Geomfromtext (‘linestring (115.97166453999147 28.716493914230423106.00231199774656 29.719258550486572) ‘and ST_MakeLine( ST_MakePoint(115.97166453999147,28.716493914230423), ST_MakePoint(106.00231199774656,29.719258550486572) )Equivalent ST_ Geomfromtext (‘point (115.97166453999147 28.716493914230423) ‘, 4326) and ST_SetSRID(ST_MakePoint(115.97166453999147,28.716493914230423),4326)Equivalent ST_ Setsrid (st_makepoint (115.97166453999147,28.716493914230423), 4326): geography and Geography(ST_SetSRID(ST_MakePoint(115.97166453999147,28.716493914230423),4326))、 ST_GeographyFromText(‘SRID=4326;POINT(115.97166453999147 28.716493914230423)’)Equivalent (: geography […]

  • How to enable redis cache with springboot

    Time:2022-5-26

    catalogue Redis cache Main steps Concrete practice Overall directory structure Configure redis cluster in YML file Set serialized bean Write business controller Additional notes on caching Inspection results Didn’t you say that redis can be used as a cache beforeNow let’s configure the redis cache used by springboot Redis cache Why use redis as cacheThe […]

  • There are tables in Oracle library, but the query shows that the table does not exist

    Time:2022-5-26

    Log in to the database as sys or system or other user with DBA authority (able to query the view of system data dictionary), and execute the following query: select owner from dba_ tables where table_ Name = ‘table name’; If it is different from your current login user, you need to bring the user […]

  • Answers to several MySQL high-frequency interview questions

    Time:2022-5-26

    preface: In various technical job interviews, it seems that MySQL related questions are often asked. Whether you are interviewing for a development position or an operation and maintenance position, you will always ask a few database questions. My friends often send me private letters asking how to deal with MySQL interview questions. In fact, many […]

  • Detailed analysis of transactions and locks in SQL Server

    Time:2022-5-26

    A few days ago, I “read” two translated Chinese versions of “SQL Server 2005 advanced programming” and “SQL Server 2008 programming introduction classic (3rd Edition)”. It is found that the directory structure is roughly the same, and the contents explained are almost the same. Suspected of plagiarism. In the “transaction and lock” page, I found […]

  • Redis visualization tool redisinsight

    Time:2022-5-25

    Redisinsight Ubuntu deployment of redis visualization tool 1、 Download redisinsight 2、 Disposition 3、 Run redisinsight 4、 Use Redisinsight: monitor redis Use the browser based management interface to check redis data, monitor health status and execute runtime server configuration for redis deployment. Explore and interact with your redis data Reduce redis memory usage Real time monitoring […]

  • Springboot notes (III) redis

    Time:2022-5-25

    Redis database **Soul torture: * * didn’t you learn MySQL and save data? Why do you learn another database? Previously, we learned MySQL database, which is a traditional relational database. We can use Mysql to better manage and organize our data. Although in small web applications, only a MySQL + mybatis built-in cache system can […]

  • Redisjason Chinese full text retrieval

    Time:2022-5-25

    Redisjason Chinese full text retrieval RedisJson Redisjason, which is popular on the Internet recently, is believed to be familiar to everyone. There is also a performance post that says yesRedisjason was born in the sky, with the performance of ES and Mongo!Of course, these hundreds of times improvements may be more objective. I am more […]