[Ubuntu]: 18.04.4 LTS
[Apache]: Apache/2.4.29 (Ubuntu)
[MySQL]: Ver 14.14 Distrib 5.7.29, for Linux (x86_64) 
[PHP]: 7.2.24-0ubuntu0.18.04.3 (cli) 

MySQL Does Not Reuse Exisitng Connection.

SELECT * 
FROM INFORMATION_SCHEMA.PROCESSLIST 
WHERE DB="mySchema" and state <>"executing" order by id;    

Upto 10 Connections are created. Once these connections are created, the connections begin to be reused and the TIME column is reset . Surely 1 connection should be created and reused.

Replicated on GCloud LAMP Install and Local Machine LAMP Install. Not able to replicate on Local Machine WAMP Install.

To replicate:

1. Create a PHP script to connect to a MYSQL table, for example the one below.
2. Run the script 10 times, wait for 10 seconds between each execution.
3. Note that upto 10 connections are created. 4 .Note that once these connections are created, the connection is reused, and the TIME column is reset.

my code:

<?php
$options = [
PDO::ATTR_ERRMODE=>PDO::ERRMODE_EXCEPTION,
PDO::ATTR_PERSISTENT=>true
];
$conn = new PDO("mysql:host=localhost;dbname=mySchema", "myUser", "myPassword", $options);
$stmt = $conn->query("SELECT * FROM myTable;");
$row=$stmt->fetch(PDO::FETCH_NUM);
$conn = null;
?>