PHP 72的数据库查询速度太慢

Question

IMPORTANT: I reported this terrible result of PHP 7.2 at https://bugs.php.net/bug.php?id=76565 . I tried this with PHP 7.0.30 and also with PHP 7.1.13 and the problem is exactly the same: much much much slower queries in comparson with PHP 5.4.16.

PHP 7.2 is very fast, amazingly fast. Doing very simple benchmarks (like looping thousands of times and doing some basic arithmetics) demonstrates that PHP 7.2 is easily 3x faster than PHP 5.4.16 (which is the default PHP version that comes enabled to be installed on Centos 7 using the "yum").

BUT for some strange reason doing DB queries is AT LEAST 2X slower - at least.

I booted 2 CENTOS servers - identical. Then on one I installed PHP 5.4.16 and in the other I installed PHP 7.2 (both were running the latest version of MariaDB).

Then I created a simple database and executed the benchmarking below:

<?php

include("connect.php");

$microtime = microtime(true);

for ($i=0;$i<100;$i++) {

    $query = "SELECT * FROM table WHERE id = 'xxx'";
    $result = mysqli_query($connection,$query);
    $data = mysqli_fetch_array($result);

}

echo microtime(true) - $microtime;

?>

I executed this code at least 5 times on each server, allowing some delay between tests. They were very clear:

PHP 7.2 took about 4.5 seconds to run PHP 5.4.16 took about 1.1 seconds to run

So what? Is there something with PHP 7.2 that I am not aware that I should be taking into account when querying db?

EDIT

Replying some comments:

1) to install PHP 5.4.16 I just did this:

yum install php php-mysql mariadb

2) to install PHP 7.2.7 I first installed REMI, then I did this:

yum install yum-utils
yum-config-manager --enable remi-php72
yum install php php-mysql mariadb

The connection to the DB is made with this code:

$connection = mysqli_connect("localhost","root","----");
mysqli_select_db($connection ,"database");

I am aware of a bug regarding using "localhost", but I also tried "127.0.0.1" and the results were the same, so using "localhost" in this case does not change anything.

I just checked right now, both servers have same CPU (double checked using cat /proc/cpuinfo ) and same SSDs. Ram is the same and RAM consumption is very close when using the command free .

Answer 1

I cannot reproduce such difference.

You seems you have some very big table / row, as I have to increase the loop to 10000 to have 1/2 second, on a small RHEL-7.5 VM

• PHP Version 5.4.16 in 0.55" (using php-mysql and libmysqlclient)
• PHP Version 5.4.16 in 0.65" (using php-mysqlnd)
• PHP Version 5.5.38 in 0.66"
• PHP Version 5.6.36 in 0.65"
• PHP Version 7.0.30 in 0.67"
• PHP Version 7.1.19 in 0.67"
• PHP Version 7.2.7 in 0.69"
• PHP Version 7.3.0alpha2 en 0.55