How PHP solves the problem of high concurrency

How to use PHP Solve the problem of high concurrency ？（ Source code attached ）-php course -PHP Chinese net The last article introduced 《 Let's learn more PHP Process control statement if Statement! ！！！( Source code attached )​》, This article continues to introduce to you PHP Solve the problem of high concurrency https://www.php.cn/php-weizijiaocheng-476799.html

1. Pessimistic locking , Put the inventory field number Field set to unsigned, When the stock is 0 when , Because fields cannot be negative , Will return false, When high concurrency comes , It may cause the number of connections to run out , The system database crashed
2. Use for update , Lock the row of the action
3. FIFO, Use Redis fifo , But this kind of turns into the shadow of single thread , If there is not enough memory, it will still be abnormal
4. File lock , When file locks are used in key methods , Only after this operation can the lock be released .
5. Optimism lock , Add one more version Field to determine whether it has been updated , However, if there is a delay in using master-slave, you should force reading the master database .
6. Use redis Of watch

<?php

$redis = new redis();

 $result = $redis->connect('127.0.0.1', 6379);

 echo $mywatchkey = $redis->get("mywatchkey");

 echo " Panic buying ！<br/>";

       

        echo " The remaining quantity ：".($rob_total-$mywatchkey-1)."<br/>";

        echo " User list ：<pre>";

        var_dump($mywatchlist);

    }else{

          $redis->hSet("watchkeylist","user_".mt_rand(1, 9999),'meiqiangdao');

        echo " Bad luck , Buy again ！";exit;

    }

}

?>

php How to solve the problem of high concurrency - big data - Billion speed
PHP High concurrent programming _ Strive to be an interesting person's blog -CSDN Blog _php Concurrent programming