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database version select version ();• View database status show status;(data not all shown)• View each parameter show variables; Show variables like ' max_connect% ';Show variables;(Too many parameters)• Modify parameter set global max_connect_errors=1000;If you want to permanently take effect, you need to exit to SHELL,VIM/ETC/MY.CNF, define max_connect_errors=1000;• View queue show processlist; Show full processlist;If there are errors, please correct, learn from each other and progress togeth

rows affected (0.01 sec)• Completely delete the database:Drop database db1;mysql> drop Database db1; Query OK, 1 row affected (0.01 sec) 13.6 MySQL Database backup recovery• Backup library:Mysqldump-u User name-p password Database > backup data file path[Email protected] ~]# mysqldump-uroot-p123456 mysql >/tmp/mysql.sql(Too much data is not listed)• Recovery library:Mysql-u User name-p password Database [Email protected] ~]# mysql-uroot-p123456 MYSQL2 • Backup table:Mysqldump-u Use

the WHERE clause is used in the inch , not in , or or having . can use exist and the Not exist Replace inch and the not in . You can use table links instead exist . Having can be replaced by where , if not replaced, can be handled in two steps. ExampleSELECT * from ORDERS WHERE customer_name not in(SELECT customer_name from CUSTOMER)Optimized SELECT * from ORDERS WHERE customer_name not exist(SELECT customer_name from CUSTOMER)7.2 do not declare numbers in character format, you want to dec

10.28 Rsync Tools IntroductionThe file Synchronization tool rsync, can achieve incremental copy, CP is direct coverage, low efficiency;Install rsync, #yum-y install rsync;Rsync Common methods,Copy the passwd file to the/tmp directory, rename it to 1.txt, and the command to #rsync-av/etc/passwd/tmp/1.txt-V visualization;Remote copy, command for #rsync-av/etc/passwd [email protected]:/tmp/1.txt; then enter the password;10.29/10.30 rsync Common Options10.31 rsync sync via ssh-e Specifies the port,

();-------------------------------------------------------------------curl-x127.0.0.1:80 test.com/upload/3.php //Can not parse, directly to the source code (written content) display/usr/local/nginx/sbin/nginx-t/usr/local/nginx/sbin/nginx-s Reloadcurl-x127.0.0.1:80 test.com/upload/3.php //Normal parsingTail/usr/local/nginx/logs/error.log//View error log12.16 Nginx AgentCd/usr/local/nginx/conf/vhostVim proxy.conf//Add the following:-----------------------------------------------------------------

Tags: Linux notes12 weeks three sessions (April 25)12.10 Nginx Access Log12.11 Nginx Log Cutting12.12 static files do not log logs and expire time12.10 Nginx Access LogThe format of the configuration file is in the main configuration file.Search for log to find the following paragraph, which is used to define the format.Public network IP, in Baidu, search IP, view.Defining Access Log pathsOpen FileUnder}, add a row to read as follows:12.11 Nginx Log CuttingEdit FileAdd the following contentProce

= ' date-d '-1 day +%y%m%d '//similar to 20180427, yesterday's date, today 28thLogdir= "/data/logs"Nginx_pid= "/usr/local/nginx/logs/nginx.pid"CD $logdirFor log in ' ls *.log 'DoMV $log $log-$dDone/bin/kill-hup ' Cat $nginx _pid '--------------------------------------------------------------------------------------Add Task Schedule #crontab-e//write the following:0 0 * * */bin/bash/usr/local/sbin/nginx_logrotate.sh//Daily 0 o'clock in the morning execution12.12 static files do not log logs and e

How to solve the grub error during startup-pain lessons-general Linux technology-Linux technology and application information. The following is a detailed description. If you have installed more than two systems (I am talking about Ubuntu), Grub will be used for guidance. I have tried this situation, when xp and ubuntu are started, grub loading please wait appears during startup ...... Error 17 or error 15 I have never seen such a situation before. W

During happy pregnancy, the APP has been unavailable for a few months, but there are still four to five users each day. Although the project failed, but in general, it is more successful than the previous debate project. Now let's summarize: Experience: 1. The product orientation must be urgent and helpful to users to solve users' actual problems. (Solve actual problems during pregnancy, and there are still users visiting each day) 2. products must meet users' psychological needs. (Through th

The following are some of the lessons I've been inspired by the software development process over the years, as well as the good experiences that have been summed up.Development starts from the trivial and then expandsWhether it's creating a new system or adding new functionality to an existing system, I always start with a version that's simple enough to have almost no functionality, and then fix the problem step-by-step until you're satisfied. I hav

unspoken intention is to do so. The result is that the next day to study the problem, the solution is ready to go.21. Job-HoppingDon't be afraid to switch jobs. It is very interesting to work with different people, to develop different products and to feel different company culture.22. Continuous LearningWe need to constantly learn and understand software development. You can try different programming languages and tools, read the software development books, and accept the MOOC course. Believe

Testing to do is confused, is to do a balm, or drift, I do not know, but I know that-I want to do a good test, can affect more people's testing. Perhaps because of a variety of reasons, do not feel the value of testing, but want to make their own value, first let yourself worth, and then you are worth the value of the show you.How far can you go without a coded test? So programming is bound to be, no matter when, perhaps a bit extreme, but I am the position of the individual is this. (not arguin

3. Lessons learned from more than 2 million yuan of entrepreneurship-apps are not needed for entrepreneurship, but more than million apps Abstract: There is an idea to develop apps or websites, promote, continuously improve, and explore profit models. This general mobile Internet entrepreneurial process. However, I think that in some specific business models, the "R D app or website" step can be cut down or postponed. Health care sharing: Part

14 Sets of Java Premium architecture lessons, cache architecture, deep JVM virtual machines, full-text search Elasticsearch,dubbo distributed RESTful services, concurrent principle programming, SPRINGBOOT,SPRINGCLOUD,ROCKETMQ middleware, MySQL distributed cluster, service architecture, operation and maintenance Architecture Video Tutorial14 sets of fine course Introduction:1, 14 sets of fine is the latest finishing courses, are the most fire of the te

* from emp WHERE empno = ' 7369 ' 9. Sorting Avoid the use of resource-intensive operations, SQL statements with Distinct,union,minus,intersect,order by will start the SQL engine execution, resource-intensive sequencing ( SORT) feature . DISTINCT requires a sort operation , while others need to perform at least two sorting Temporary Tables Careful use of temporal table can greatly improve the performance of the system Oh. The above is brother Lian Share 10

example, many functions of SQL Server Express are not available in MySQL. SQL Server provides Management Studio, Configuration Manager, Report Server, online backup, automatic optimization, and other functions. MySQL supports different storage engines and provides partition options for easier installation. When MySQL is selected, it is important that it can run on any operating system and is open-source, and the size of the database is limited only b

. Use a client-based firewall or filter to enhance computer immunity against hacker and malicious code attacks. Or in some security websites, you can scan your computer to see if it has security vulnerabilities and viruses. This is necessary if you are always online, because your personal data may be stolen by others if your system is not effectively protected. 7. Be alert against fraudulent or advertising viruses. These viruses use the weakness of hu

The speech is recorded as follows: Today, we can see that many of our members are old friends, including those from the media and investment companies, the first purpose of this meeting today is to discuss practices from traditional media to new media. In addition, this kind of cross-industry communication is actually quite rare. Both traditional media and mobile app developers should have a good communication. I will share with you the experience of the fresh fruit team on moving from nothing.

, applicationcontext.xml and dispatch-servlet.xml form the context of two parent-child relationships, tested and found: 1) If a bean is defined in two files (for example, two files define the same package as component scan), Spring generates an instance in both application context and servlet context. They are in different contexts and they behave differently (see the problem described below). 2) If there is an instance of the same @Service in both the application context and the servlet context

of memory requirements will B,PB,RB have? Either pointer or reference requires only one word space (32 is 4-bytes on the machine). Bear object needs 24bytes, that is, Zooanimal's bytes plus the 8 bytes that bear brings.Well, suppose our bear object is placed at address 1000, what is the difference between a bear pointer and a zooanimal pointer?Bear B;Zooanimal *pz = b;Bear *PB = b;Each of them points to the first byte of a Bear object. The difference is that PB covers an address that contains t