Weird behaviour for DNS resolution

[kirby0025]

Description

I have look on the internet and see very little talk about this so it's possible that my php is wrongly configure but I have failed to find a directive related to this.

The following code:

Not sure where the code is located, my C understanding is pretty weak and I'm an ops guy.
I think it's around here : https://github.com/php/php-src/blob/master/ext/standard/dns.c

What I see :

When a php process does a dns query for both A and AAAA type, if A is valid but AAAA is empty, both records are not stored in cache and therefor the next request will trigger a dns query for both type again.
It seems like the empty AAAA response triggers an invalidation in the cache for both A and AAAA record. This behaviour floods the network needlessly.
I have notice this behaviour both on VMs or on containers, and from a wide range of php versions (5.6 to 8.3) or OS versions (Debian 9/10/11/12, Ubuntu 16/18/20/22 or Alpine 3.18/3.19).
I can provide this graph to illustrate better what I'm saying (Yellow and Green line are AAAA and A type) :

What I would expect :

In my opinion, once a A record have been successfully retrieved, it should be stored in cache and the AAAA should not invalidate it. And maybe once the A record expires it should try again both resolution (A and AAAA).

I have tested successfully to disable ipv6 in kernel for VMs and it drastically reduces the number of DNS query sent by applications (see graph below) and looks like the A response is stored in cache. This is a possible solution for VMs but complicated one in a Kubernetes environment.

PHP Version

8.3

Operating System

No response

[devnexen]

I am not sure we can have any influence in that regard, to my knowledge, with libresolv. cc @Girgias @kocsismate ?