Simply said: If a mysql host, say, allows only 10 connections at the same time and you have 11 visitors at the time, that will exceed since every visitor has its own instance. According to the docs the default values is normally 151.

I checked and our MySQL server allows 151 connections. So that does not seem to be the issue.

Also we do not use dynamic albums as of now and both options you mentioned are disabled.

Or do you have that many visitors that you manage 151 at one time actually? If the traffic load exceeds the server capability we can of course not do much ;-)

But regardless please try the file above…

Oh yeah.. I get that max_user_connections error when viewing the sub-albums of an album that had 23 albums in it. My max_user_connections value is set to 15 on my server. Seems related to the thumbnail generation as on the first view, a couple are not created.

In my case Options > Gallery > Gallery behaviour > Show all subalbum thumbs was already unchecked. I'll have to install 1.5.4 and go from there. I do have "Cache processing worker limit" set to 3.

@MarkRH Please also try the change in the support build to see if that helps. But 15 is really pretty low, isn't it?

We meanwhile found at least why the issue seems new to you. It was supressed via @ formerly so it was already there but you just didn't get to see it.

I have tested the support build since June 23rd now and the error did not occur again on my site.

That being said I found one very similar warning message in the debug log:

{19018:Thu, 11 Jul 2019 22:09:41 GMT}
WARNING: mysqli_connect(): (08004/1040): Too many connections in /zp-core/functions-db-MySQLi.php on line 30
mysqli_connect called from db_connect (functions-db-MySQLi.php [30])
from require_once (functions-basic.php [185])
from require_once (functions.php [18])
from include (index.php [14])
from index.php [44]

Edit: This might very well be some hiccup on the hoster end. So unless someone else experiences similar warnings, please don't overrate this.

I would really good to know when on what page this happens. As said I cannot reproduce this neither locally nor on our own live sites.

Did you limit the image processor concurrency on the option?

I'll keep an eye on it, but currently I don't have clue either.