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  How to play with cross domain request

What is cross domain request In simple, cross domain request is to request resource from other domain in one domain. Note, the "other domain" doesn't just mean domain name only, it includes much more. If the protocol, domain name, port is not the same, two domains will be considered different.  Below example describes what is considered as different domain. http://www.a.com/a.jshttp://www.a.com/b.js               # Same domainhttp://www.a.com/lab/a.js &nb...

   FRONT END,JSONP,CROSS DOMAIN,CROSS ORIGIN,CORS,DOCUMENT.DOMAIN,WINDOW.NAME     2016-11-06 00:48:54

  Why MySQL 8 drops support of query cache

Many of you may have heard or used MySQL's query cache, because it used to be a popular way to improve MySQL's performance. As an important feature for improving MySQL's performance, the query cache was often recommended as a solution for slow queries. However, why has MySQL 8 abandoned the query cache? Today, we will analyze and explore this decision. What is query cache? According to official document: The query cache stores the text of a SELECT statement together with the correspon...

   MYSQL 8,QUERY CACHE     2023-03-11 09:05:17

  Solving easy problems the hard way

There’s a charming little brain teaser that’s going around the Interwebs. It’s got various forms, but they all look something like this: This problem can be solved by pre-school children in 5-10 minutes, by programer – in 1 hour, by people with higher education … well, check it yourself!  8809=6 7111=0 2172=0 6666=4 1111=0 3213=0 7662=2 9313=1 0000=4 2222=0 3333=0 5555=0 8193=3 8096=5 7777=0 9999=4 7756=1 6855=3 9881=5 5531=0 2581=? SPOILER AL...

   Problem solving     2012-04-05 23:40:35

  Three things you should never put in your database

As I've said in a few talks, the best way to improve your systems is by first not doing "dumb things". I don't mean you or your development staff is "dumb", it's easy to overlook the implications of these types of decisions and not realize how bad they are for maintainability let alone scaling. As a consultant I see this stuff all of the time and I have yet to ever see it work out well for anyone. Images, files, and binary data Your database supports BLOBs so it must be a good idea to shove ...

   Database,BLOB,Log,Image     2012-05-02 04:44:25

  Redis Cluster and Common Partition Techniques in Distributed Cache

In this post, I will discuss a few common partition techniques in distributed cache. Especially, I will elaborate on my understanding on the use of Redis Cluster. Please understand that at the time of writing, the latest version of Redis is 4.0.10. Many articles on the same topic have a different idea from this post. This is mainly because, those articles are probably outdated. In particular, they may refer to the Redis Cluster implementation in Redis 3. Redis Cluster has been improved...

   REDIS,DISTRIBUTED CACHE,CLOUD COMPUTING     2019-01-17 08:10:37

  Guide on recovering data in MySQL

In our daily work, there might be mistakes made which got some data or even databases deleted in MySQL. If this happens on production, it would be a nightmare. In case this happens, normally DBA would jump in to save the world. And they would try to recover the data from the backup if there is any. But if there is no backup, then the show stops. Hence database backup is necessary on production environments to avoid such awkward situation. Also normally in MySQL, binlog should be enabled as well ...

   MYSQL,DATABASE,BACKUP,BINLOG,EXAMPLE     2020-08-26 07:50:30

  Use of Erlang in WhatsApp

After many years, people are still discussing whether Erlang is a small language. People have all sorts of doubt about it, but with the appearance of WhatsApp, we may change our mind. What is WhatsApp, from its official website: WhatsApp Messenger is a cross-platform mobile messaging app which allows you to exchange messages without having to pay for SMS. The more funny thing is the main developer of WhatsApp Rick Reed worked in Yahoo and SGI before he joined WhatsApp and he didn't have any know...

   Erlang,WhatsApp,Architecture     2013-06-16 03:03:46

  Removing duplicates in sql

In modern web development, it’s standard practice to make use of a database abstraction layer, typically an Object-Relational Mapper based on either the Active Record pattern or the Data Mapper pattern. There are several pros and cons to this which are fairly well established, so I’ll spare us all from enumerating them all right now. One established pro worth mentioning is that these systems typically provide a high level interface for fetching data, often removing the need to ...

   SQL,Duplicate,Remove,Web design     2012-01-05 08:20:13

  Understand unsafe in GoLang

Before going to understand unsafe package in GoLang, the first thing needs to talk about is the pointer in GoLang. If you have a background of C language, you must know what pointer means and its usage. With pointer, you are free to operate any data at memory level which means you have great power, but this means that you have great responsibility as well. That's why it might be considered unsafe in lots of cases. Take a look at a simple example of doubling an integer. package main import "fmt"...

   GOLANG,UNSAFE,ZERO-COPY     2020-03-14 23:18:00

  Output control functions in PHP

The Output Control functions in PHP allow you to control when output is sent from the script. This can be useful in several different situations, especially if you need to send headers to the browser after your script has began outputting data. The Output Control functions do not affect headers sent using header() or setcookie(), only functions such as echo and data between blocks of PHP code. These output control functions include ob_start(0, ob_clean(),ob_get_contents(), etc. To be honest, I a...

   PHP,output buffer,relationship,ob     2012-06-15 10:11:58