Hi

When I try do download a folder (album) with "Original" photos, I get an error message :

Warning: Error while sending QUERY packet. PID=22435 in /home/.../include/dblayer/functions_mysqli.inc.php on line 147

Warning:  [mysql error 2006] MySQL server has gone away

UPDATE piwibx_download_sets_images
  SET zip = 1
  WHERE
    set_id = 29
    AND image_id IN(36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75)
; in /home/.../include/dblayer/functions_mysqli.inc.php on line 845

Warning:  [mysql error 2006] MySQL server has gone away
UPDATE piwibx_download_sets SET nb_zip = "1" WHERE id = 29; in /home/.../include/dblayer/functions_mysqli.inc.php on line 845

The strange thing is that in the "admin settings" of the plugin, in "Download History", I see an entry with the request of the download, and its size (268Mo). Which means that the zip has been done and stored on my server I reckon.

My settings are
    - Maximum number of photos per download set: 500
    - Maximum size of each archive (in Megabytes): 500

It's not clear for my users of what they have to do.
There is a long lag (like 30sec) after requesting for the download, before getting this warning, and the green banner "The archive is downloading, if the download doesn't start automatically please click here".

Does anybody knows:
- how to remove those warnings?
- why do I get these warnings?
- how to display a "temporary message" while the zip is processing (more than 30sec) and tell the user to wait for the download?

Cheers, 

Piwigo version: 2.9.4
PHP version: 7.0.32
MySQL version: 10.2.18-MariaDB-cll-lve
Piwigo URL: http://worldsways.org/gallery