Programmer Think

A Restore Record of OpenProject There are problems in the use of OpenProject. The function in a task can not be used. After negotiation, users are ready to revert to the historical version. I. Prerequisites: OpenProject has backup files. OpenProject has its own backup command (open project run backup), and the backup files are located in the ...

Catalog Overview of Nginx Four-Layer Load Balancing What is Load Balancing Load balancing application scenarios Four-tier and Seven-tier Cluster Architecture Summary of Four-Layer Load Balancing How to Configure Four-Layer Load Balancing in Nginx nginx four-tier load balancin ...

Author: Hong Bin Does every DBA have experience of deleting libraries? What if you delete the library without backup? What happens when the service cannot be started after the backup recovery? What if table definition corrupted data cannot be read? I once met a startup Internet company. Because of the irregular backup and recovery operation of ...

[tcp] nginx seven-tier load balancing Overview of nginx load balancing When our Web servers are directly user-oriented, they often carry a large number of concurrent requests. It is difficult for a single server to load. I use multiple Web servers to form a cluster. The front-end uses Nginx load balancing to distribute requests to our back-end ...

1. Transaction isolation level 1.1 transaction-induced concurrency problems When multiple transactions run concurrently, if multiple transactions operate on the same data in the database at the same time, it is easy to cause concurrency problems. ...

Introduce the storage directory of MYSQL I. Location of Mysql Data Storage by Command $ mysql -u root -p Enter password: Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 10 Server version: 8.0.12 MySQL Communi ...

Syntax of form queries and priority of keyword execution Form Query Syntax SELECT DISTINCT Field 1,Field 2... FROM Table Name WHERE condition GROUP BY field HAVING screen ORDER BY field LIMIT Limi ...

        Note: The WEB server and database need to be separated, and the WEB server also needs to compile and install MySQL. The important idea of cluster architecture is to find the backbone and extend from the backbone area to the outside.   WEB Server: apache nginx makes three products locally, dedecms work process discuz, which stor ...

Define a command alias that works for all usersFor example: lftps='lftp 172.168.0.1/pub' [root@localhost /]# echo "alias lftps='lftp 172.168.0.1/pub'" >> /etc/bashrc [root@localhost /]# source /etc/bashrc [root@localhost /]# alias alias cp='cp -i' alias egrep='egrep --color=auto' alias fgrep='fgrep --color=auto' alias grep='grep --col ...

SQL form query I. Grammar of Single Table Query select List 1,List 2... from Table name where condition group by field having screen order by field limit Limited number of bars 2. Priority of keyword execution from where group by having select distinct order by limit 1. Find ...