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  How expensive is a MySQL query?

Database access speed is always the bottle neck of many applications. Many application have large amount of data to search, retrieve and display nowadays. How do we improve the performance of our applications, how do we reduce the cost of database access? Apart from the design of database, the quality of the query is also one important factor to take care.  But before that, we need to know how much network traffic a query will consume. Yunyang,Zhang from Nubee in Singapore did some research...

   MySQL,Network traffic,Query     2013-04-09 05:13:33

  Reproduce "MySQL server has gone away" in PHP

If you want to debug the issue of "MySQL server has gone away", you can reproduce it with below steps: Modify configuration file: sudo vi /etc/mysql/my.cnf  Make below changes: [mysqld]   wait_timeout = 30   interactive_timeout = 30  Restart the service: sudo /etc/init.d/mysql restart  Write below PHP codes: $link = mysql_connect('127.0.0.1', 'root', 'root');   if (!$link)&nbs...

   MySQL,debug,rMySQL server has gone away     2013-04-15 11:33:14

  Sites to go if you want to learn web development

Before you start to do web development, either for a hobby or for your start up project, you should be prepared for learning many different technologies including both front end and back end. You may need to deal with UI design, business logic design, data store and infrastructure setup etc. This seems a very complex. Indeed, if you know where you should go, the  it's actually not so hard. Here are some sites you should go when you face issues while you are doing web development. These site...

   Web development,Resource,Site     2013-09-19 08:12:23

  App's user value doesn't necessarily bring business value

There is an old saying in Internet world, you can get business value as long as you can achieve user value. Is this statement outdated in mobile Internet era? This statement originated from PC Internet era, but now the time users spend on PC drops and user behavior tends to be stable and conservative. In contrast, people are more willing to stay on mobile devices. The difference between PC and mobile is that users are freely to move around on PC end. People can navigate from one link to another ...

   App,Business value,User value     2013-06-25 10:52:12

  SQLite C/C++ function interfaces

Some simple introduction to the SQLite function interfaces. First let's check some error codes defined in SQLite3 (They are in SQLite3.h file in the SQLite installation).#define SQLITE_OK           0   /* Successful result */  /* beginning-of-error-codes */  #define SQLITE_ERROR        1   /* SQL error or missing database */  #define SQLITE_INTERNAL     2&nb...

   SQLite,Function interface,C/C++     2012-07-04 12:23:43

  How Kafka achieves high throughput low latency

Kafka is a message streaming system with high throughput and low latency. It is widely adopted in lots of big companies. A well configured Kafka cluster can achieve super high throughput with millions of concurrent writes. How Kafka can achieve this? This post will try to explain some technologies used by Kafka. Page cache + Disk sequential write Every time when Kafka receives a record, it will write it to disk file eventually. But if it writes to disk every time it receives a record, it would ...

   BIG DATA,KAFKA     2019-03-08 09:42:57

  How to optimize MySQL insert statement

For a big data system, one problem is the data access efficiency, one more problem is that the data insertion is very slow. We had a service system, the data loading process would take 4-5 hours. This time consuming operation is risky since if the program is interrupted during the loading process, it might be rerun, this will be troublesome. So it's necessary to improve the insertion efficiency for big data systems. Here we provide two optimization suggestions. 1. Combine multiple insert stateme...

   MySQL,insert,optimization     2012-10-24 22:03:13

  Beauty of code : How to write graceful PHP code

Writing good code is an art. In order to achieve this, it is necessary to develop good programming habits at the beginning. Good programming habits not only contributes to the early project design (modular),but also allows you to the code easier to understand, so that the maintenance of the code is easier. Bad programming habits will result in more code bugs, and will make future maintenance work difficult. We introduce some good programming habits taking PHP as example. Hope this will help you....

   PHP,Good code     2012-08-26 12:23:03

  How does MySQL handle DROP TABLE

A few days ago, when executing DROP TABLE in MySQL, all processes including DDL and DML were hung until DROP TABLE was completed. I am confused about this phenomenon. I have reviewed the source codes of MySQL to check how MySQL internally handle DROP TABLE. When user trigger DROP TABLE command: ########################MySQL SERVER drop table######################## /* Sql_table.cc  delete (drop) tables. */bool mysql_rm_table( )   /*   Execute the drop of a normal or temporary...

   MySQL,DROP TABLE     2012-09-24 11:34:05

  Spurring the Consumer Feedback Loop with Connected Devices

In a press release from earlier this year, Gartner had predicted that by the year 2018 mobile devices would account for initiating 5% of consumer services cases, registering a marginal rise of 0.02% from 2014. Research shows that most businesses lose around a whopping $83 billion owing to poor consumer services (Source: kissmetrics) in the US alone while globally, the average cost of losing a consumer is $243. It is only viable to think of automating support services as a way to lower the costs ...

   Big Data Analytics Solutions, Loyalty Programs for Customers     2015-08-18 07:11:35