Web Development
Web Development

PHP OCR business license recognition

... Jayce
schedule1 min read
Web Development

Use the API to create items under the account

... Timothy
schedule1 min read
Web Development

Startup script and cronolog log segmentation

... Bentley
schedule3 min read
Web Development

my php & mysql FAQ

php Chinese character string length and fixed-length interception problem Use str_len("China"), the result is 6. The php system defaults a Chinese character length of 3, you can use the mb_strlen function to obtain the length, and the mb_substr function to intercept the characters mb_strlen($str, "utf -8"); //1 Chinese character is 1 character mb_strlen($str, "gb2312"); //The system will consider 1 Chinese character to be 2 characters mb_strlen($str); //If not added, the system will consider 1 C

... Adriana
schedule6 min read
Front End Technologies
trending_up Front End Technologies

Simple use of regular position matching

... Bryce
favorite1386
trending_up Front End Technologies

"Pro Git" reading notes 1

... Avery
favorite312
trending_up Front End Technologies

git basics

... Brandon
favorite1516
trending_up Front End Technologies

Promise basics

... Asher
favorite233
trending_up Front End Technologies

Function curry (Haskell Curry)

... Hannah
favorite1850
trending_up Front End Technologies

Several methods to clear floats

... Matthew
favorite523
Javascript
Javascript

Front End Data Structure and Algorithm (14): 01 The Art of Execution-Backtracking Algorithm (Part 2)

PrefaceFollowing the book, the previous chapter made a progressive introduction from recursion to backtracking. I believe that I have a preliminary understanding of backtracking. Next, I will mainly introduce more topics related to backtracking, and deepen its understanding in breadth.Alignment problem46-Full arrayGiven a sequence without repeated numbers, return all possible permutations. Example: Input: [1, 2, 3] Output: [ [1,2,3],[1,3,2],[2,1,3], [2,3,1],[3,1,2],[3,2,1] ] Source: LeetCode Lin

... Melanie
schedule16 min read
Javascript

Front end data structure and algorithm (13): 01 The Art of Execution-Backtracking Algorithm (Part 1)

... Carter
schedule16 min read
Javascript

Front end data structure and algorithm (12): Interesting algorithm-multi-pointer and sliding window

... Nolan
schedule6 min read
Javascript

Front-end data structure and algorithm (11): A binary search algorithm that seems simple and maddening

... Cora
schedule19 min read
Server Side Programming
Server Side Programming

Build a three-node high-availability architecture based on MySQL 5.7 multi-source replication and Keepalived

Basic environment preparationUse Centos 6.X 64-bit system using MySQL MySQL-5.7.17-x86_64version, go to the official mysql-5.7.17-linux-glibc2.5-x86_64.tar.gzversionMachine nameoperating systemIPnode1centos-6.8192.168.11.100node2centos-6.8192.168.11.101node3centos-6.8192.168.11.102Set the VIP of the three-node cluster to 192.168.11.110Generally we recommend closing iptables[wubx@zhishuedu.com ~]# chkconfig —del iptables [wubx@zhishuedu.com ~]# /etc/init.d/iptables stopAnd close selinux[wubx@zhis

... Benjamin
schedule 3 min read
Server Side Programming

The whole process of troubleshooting memory leaks and OOM issues under MySQL 5.7

GuideMy personal website uses MySQL version 5.7 in the backend. Some time ago, I was often killed by oom-kill. With the help of new features in 5.7, after some investigation, I finally caught this ghost.1. Problem phenomenonSome time ago, my website often got wind from time to time, prompting that the database could not be connected, prompting:Error establishing database connectionI thought it was a personal website anyway, and it didn’t matter. It might also be because the VPS configuration is

... Isaac
schedule 6 min read
Server Side Programming

SQL optimization in partitioned table scenarios

GuideOne table is partitioned, one partition per day.There is a query on this table. It often only queries the data of a certain day in the table, but almost all data in the entire partition is scanned every time. Is there any way to optimize it?Scene to be optimizedThere is a large table, the amount of data generated every day is about 1 million, so the table partitioning scheme is adopted, one partition per day.Here is the DDL of the table:CREATE TABLE `t1` ( `id` bigint(20) NOT NULL AUTO_INCR

... Mark
schedule 5 min read
Server Side Programming

Optimization case: CASE WHEN for SQL rewriting optimization

GuideToday, I will share with you a SQL optimization case that is unique through SQL rewriting.Scene to be optimizedFound the following record in SLOW QUERY LOG:... # Query_time: 59.503827 Lock_time: 0.000198 Rows_sent: 641227 Rows_examined: 13442472 Rows_affected: 0 ... select uid,sum(power) powerup from t1 where date>='2017-03-31' and UNIX_TIMESTAMP(STR_TO_DATE(concat(date,'',hour),'%Y-%m-%d %H'))>=1490965200 and UNIX_TIMESTAMP(STR_TO_DATE(concat(date,'',hour),'%Y-%m-%d %H'))<14921748

... Daniel
schedule 7 min read
Server Side Programming

MySQL FAQ series: How to view the current latest transaction ID

Written in the front: In some cases, you may need to check the current latest transaction ID in order to make some business logic judgments (for example, use the transaction ID change and the time difference before and after, and count the response time of each transaction, etc.).Generally, there are two ways to view the current transaction ID:1. Execute SHOW ENGINE INNODB STATUS to view transaction related information==================================== 150303 17:16:11 INNODB MONITOR OUTPUT ===

... Carter
schedule 5 min read
Server Side Programming

MySQL FAQ Series-How to swap two table names

problemA classmate asked me, in a scenario similar to pt-osc, the two table names need to be swapped, how can I be sure of everything?analysisIt is estimated that the other students laughed. Isn’t it easy to rename the table names? Rename each other.However, what we want is to complete the table name swap at the same time. If it is reversed one after another, it may cause some data write failures. What should we do?ReplyIn fact, it is not difficult. You can find a method from the MySQL manual, t

... Sydney
schedule 2 min read
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