Programming VIP

1. Why divide tables?The database data becomes larger and larger, with too much data in a single table.This results in slower queries and database performance bottlenecks due to the lock mechanism of tables, which can seriously affect application operations.One mechanism in mysql is table and row locking to ensure data integrity.A table lock m ...

Asynchronous Download 1, Background At present, the system is slow to download large files, slow to export, a large number of interfaces occupy server bandwidth and other problems, which seriously affect the user experience. Based on this background, the asynchronous download function is developed and implemented. 2, Project structure Brain ...

useradd command Function Description: add user or update default new user information Usage: useradd [options] login_name option explain -u，--uid UID When adding a new user, specify the UID number manually. The default is the UID+1 of the previous user, the UID usage range (CentOS6) 500 +, (CentOS7) 1000+ -g，--gid group_name When a ...

Ctssecuritytestcases - listeningportstest locates tcp port and pid [problem description] cts failures armeabi-v7a CtsSecurityTestCases android.security.cts.ListeningPortsTest#testNoListeningLoopbackTcpPorts Tool: 9.0 μ R11 05-06 17:11:28.649 17375 17391 E TestRunner: android.security.cts.ListeningPortsTest$ListeningPortsAssertionError: 05-0 ...

Open the source code directly, see that it is a file upload, check the file size and pass a Check() function judgment, and take a look at the Check() function function Check(){ $BlackExts = array("php"); $ext = explode(".", $_FILES["file"]["name"]); $exts = trim(end($ext)); $file_content = file_get_contents($_FILES["file"]["tmp ...

18.11 LVS DR mode construction preparation Three machines have public IP. Scheduler (director) IP: 192.168.230.135 real server1(real1) IP: 192.168.230.130 real server2(real2) IP: 192.168.230.145 VIP: 192.168.230.200 Start building Configure director [root@cham002 ~]# vim /usr/local/sbin/lvs_dr.sh #! /bin/bash echo 1 > /proc/s ...

for loop General format: for var in item1 item2 ... itemN do command1 command2 ... commandN done Write in one line: for var in item1 item2 ... itemN; do command1; command2... done; eg: Requirement: sum the numbers from 1 to 100. [root@dl-001 sbin]# vim sum.sh #!/bin/bash sum=0 for i in `seq ...

7, Knowledge and practice of if structure conditional sentence (1) if conditional single and double branch syntax 1. Single branch if condition then instructions fi 2. Bifurcate if condition then instructions else Instruction set 2 fi (2) if conditional multi branch statement 1. Structure of statement if condition 1 then ...

sys: Introduction: it mainly includes functions related to the interaction between python compiler and system. Common functions: import sys print(sys.argv)#Name of this file,Parameters when the program is already running #[As in the command window python3 mysys.py Parameter 1 Parameter 2] #Then parameter 1 is sys.argv[1],And so on print(sys. ...

Operators and related topics Operator assignment Assigning, initializing, or modifying the value of a variable = A general assignment operator that can be used for arithmetic and string assignments. var=12 car=bmw # Cannot have a blank character after the = sign Don't confuse = assignment operator with = test operator ...