Does RDS Proxy support long-lived connections?

Hi,

I have a problem with long-lived connections and RDS Proxy, does RDS proxy a connection that live more than 24 hours? I have found out that every 24 hours all connections from my client to the proxy are terminated by the proxy.

According to the documentation: https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/rds-proxy-managing.html -> MaxIdleConnectionsPercent

RDS Proxy considers a database connection in it's pool to be idle when there's been no activity on the connection for five minutes.

RDS Proxy closes database connections some time after 24 hours when they are no longer in use. The proxy performs this action regardless of the value of the maximum idle connections setting.

So to keep a connection alive I thought that could be enough to "ping" the database with a "SELECT 1" with a frequency < 5 minutes but I made several tests with my java app and every time the proxy close the connection after 24 hours.

To reproduce the problem I have wrote a minimal PHP script:

<?php

ini_set('error_reporting', '1');
ini_set('display_errors', '1');
ini_set('display_startup_errors', '1');
ini_set('memory_limit', '256M');
ini_set('max_execution_time', '0');


$hostname = 'host';
$username = 'user';
$password = 'pass';
$database = 'db';

$conn = mysqli_connect($hostname, $username, $password, $database);

if (!$conn) {
	die("Error on connection: " . mysqli_connect_error());
}

while (1) {

	$query = "SELECT 1";
	$result = mysqli_query($conn, $query);

	if ($result) {
		echo date("Y-m-d H:i:s") . ': SELECT 1' . "\n";
	} else {
		echo "Error: " . mysqli_error($conn) . "\n";
		exit;
	}

	sleep(120);
}

The output is:

$ php -q test.php
2023-09-03 07:49:52: SELECT 1
2023-09-03 07:51:52: SELECT 1
2023-09-03 07:53:52: SELECT 1
.....
.....
2023-09-04 07:45:53: SELECT 1
2023-09-04 07:47:53: SELECT 1
2023-09-04 07:49:53: SELECT 1
Error: MySQL server has gone away

exactly after 24 hours I the connection is dropped and on the logs of the proxy I get:

2023-09-04T07:50:05.001Z [INFO] [proxyEndpoint=default] [clientConnection=1192216169] The client connection closed. Reason: The connection exceeded the maximum connection duration.

So does RDS proxy support long-lived connection? I haven't read anywhere in the doc that are not supported, instead here: https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/rds-proxy-planning.html

the doc says:

Applications that keep a large number of connections open for long periods are typically good candidates for using a proxy.

why ALL the connections are dropped after 24 also if they are NOT idle? I had the same problem also on connections that are running a period task that are not simple 'SELECT 1'

regards