ClickHouse goes from getting started to mastering
ClickHouse From Beginning to Proficiency (3)
ClickHouse Advanced
Explain View Execution Plan
To view the execution plan of an sql statement before Clickhouse version 20.6, you need to set the log level to trace in order to see it, and you can only actually execute sql and view it in the execution log. Native execution plan syntax was int ...
Posted by Harbinger on Mon, 25 Apr 2022 19:06:16 +0300
Spring boot integrates sharding JDBC to realize annual database and monthly table
Spring boot integrates sharding JDBC to realize annual database and monthly table (implementation and brief analysis)
1. Preface:
This scheme is applicable to the horizontal segmentation of data with high time dependence. If you just meet the requirements, you can take a look at this article. If you do not meet the requirements, you can also ...
Posted by NDF on Mon, 25 Apr 2022 07:15:59 +0300
Install Nebula Graph for macOS. Just read this article
This article was first published in Nebula Graph Community official account
background
Just learned the content of graph data. At present, the Internet is full of a large number of installation documents, which are uneven, and the deployment is very troublesome.
Now I'm sorting out a relatively complete installation document for your refer ...
Posted by ricmetal on Mon, 25 Apr 2022 06:55:24 +0300
Containerization ｜ restore RadonDB MySQL Cluster Data in S3 backup
Authors: Cheng runke, Qian FenVideo: Qian FenIn the previous article, we demonstrated how to quickly implement MySQL high availability cluster deployment and the verification and unloading method of deploying the cluster. This article will demonstrate how to backup and restore a cluster.The deployment version is RadonDB MySQL Kubernetes 2.1.3.E ...
Posted by bamfon on Mon, 25 Apr 2022 06:06:50 +0300
JDBC learning notes 02 [detailed explanation of ResultSet class, JDBC login case exercise, detailed explanation of PreparedStatement class]
Dark horse programmer - JDBC document (Tencent micro cloud) JDBC notes pdf: https://share.weiyun.com/Kxy7LmRmJDBC learning notes 01 [JDBC quick start, detailed explanation of various classes of JDBC, CRUD exercise of JDBC][day01]JDBC learning notes 02 [detailed explanation of ResultSet class, JDBC login case exercise, detailed explanation of P ...
Posted by lelelow on Mon, 25 Apr 2022 03:04:53 +0300
MySQL log management, backup and recovery of database
Study preparation: first create a table (I use the previous table here)
mysql -u root -p
create database school;
use school;
create table class(
id int(10) not null,
name varchar(20) not null,
sex char(2) not null,
cardid varchar(20) not null,
phone varchar(11),
address varchar(50));
desc class;
insert into class values ('1','zhangsan', ...
Posted by omniuni on Mon, 25 Apr 2022 00:29:16 +0300
Memory structure of Dameng database
Memory structure
SQL buffer:
explain
It is used to store SQL statements, execution plans and result sets. The default result set is closedCACHE_POOL_SIZE: the default value is 200. For complex systems with many SQL types and Pkgs, it is recommended to increase this parameter
select * from v$parameter where name = 'CACHE_POOL_SIZE';
--0 ...
Posted by fitzsic on Sat, 23 Apr 2022 10:38:54 +0300
Shiro security framework introduction read this article is enough
Introduction to Shiro security framework
Shiro security framework actual combat: Based on the separation of front and rear ends, technology selection: springboot 2 X + MySQL + mybatis + Shiro + redis + idea + jdk8, link address: [recent update]
1, ACL and RBAC explanation of permission framework design
1. Concept of permission control
Wh ...
Posted by robs99 on Thu, 21 Apr 2022 01:25:00 +0300
🍖 Use of pymysql module
introduce
1. What is pymysql
**pymysql * * is a third-party module (Library) used to operate mysql in Python (that is, a mysql client)
pymysql is a module after Python 3, and MySQL DB is used to operate the database in Python 2
You can also use pymysql to connect to the mysql database in Django
2. Installation of pymysql
Terminal command lin ...
Posted by nitharsanke on Wed, 20 Apr 2022 23:43:17 +0300
[MySQL core statement query] required for data analysts
This article data analyst must see! Last time I talked about the basics of database and mysql. This time, let's learn some of the most commonly used core query statements in MySQL.
The framed part is the focus of this section
1, Single table query
SELECT Field name FROM Table name WHERE condition [GROUP BY Field name HAVING condition ORDER ...
Posted by Jaspal on Wed, 20 Apr 2022 16:58:51 +0300