About the solution to PHP randomly recording mysql rand() causing CPU 100%

This article mainly introduces the solution to php randomly recording mysql rand() causing CPU 100%. It has a certain reference value. Now I share it with you. Friends in need can refer to it

mysql The database has tens of thousands of data, and rand() is used to extract 10 random records, causing the server CPU usage to remain high until it crashes~

Baidu consulted some information, combined with some of its own experience, and adopted the following solution Method:

$idlist=''; 
for($i=1;$i<=20;$i++){ 
if($i==1){ 
$idlist=mt_rand(3,25216); 
} 
else{ 
$idlist=$idlist.&#39;,&#39;.mt_rand(3,25216); 
} 
} 
$query="select * from table where id in ($idlist) LIMIT 0,10";

The principle is actually very simple, that is, generate a set of random IDs, and then retrieve the records corresponding to this set of IDs. After such optimization, the page opening speed is obviously much faster, and the CPU usage is almost as small as It is 0, haha~ By the way, I also optimized the sqlserver site using this idea!
Speed ​​comparison:
It takes more than 400 milliseconds to use rand() to get 10 random records, but it only takes about 0.6 milliseconds to use the above method. The difference is huge! ! !

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