White screens coming up irregularly

[k92]

Hi all,

many of my customers tell me that they're seeing white screens when visiting my shop.
It seems to happen irregularly and I was not able to see this white screen on my own.
My customer tell it happens for example when they put something in the cart, when they open a product or just when they visit my shop.

It doesn't happen every time but if they see this white screen, they have to wait for a couple of minutes, reload the page and then it's gone and they can visit my shop.

I tried to figure out what's happening by using different browsers and devices, opening several products etc. but never a white screen came up.

I guess there could be a problem with my database, server or cache.
Maybe there's an overload?

How can I figure out what the problem is and how to solve it?

Every help is highly appreciated, thank you in advance!

EDIT:
Joomla! 3.9.13
VirtueMart 3.6.8 10197
PHP 7.3.12
Custom template: yes

EDIT2:
In the com_virtuemart.log.php there are many entries of

Code Select Expand

ERROR vmError: Max execution time reached in model product getProduct() 1234567
(The number at the end is a random number by me, there are different products listed here).

EDIT3:
I just compared the php values for 'max_execution_time' and 'memory_limit' both in the Joomla config and in a separate php script with phpinfo().
The script is in the same folder as the shop.

Joomla backend system info:
max_execution_time = 50000
memory_limit = -1

phpinfo():
max_execution_time = 30
memory_limit = 128M

This can't be right because there are different values?
Which one are right? I'm confused...

[Jörgen]

VM version ... ?
Joommla version ... ?
Php version ... ?
Custom template ... ?
Live URL ... ?

Jörgen @ Kreativ Fotografi

[k92]

VM version ... ?
Joommla version ... ?
Php version ... ?
Custom template ... ?
Live URL ... ?

Jörgen @ Kreativ Fotografi

Thanks, I added some more info to my original post.
I can't tell the live url since it's one of my customer's shops and I'm not allowed to publish it here.

The problem appears for several months already so I'm not sure if it has something to do with my Joomla or VM version.

[PRO]

http://forum.virtuemart.net/index.php?topic=140606.0
https://network.convergenceservices.in/forum/46-virtue-mart/3620-solved-vmerror-memory-limit-reached-in-model-product-getproduct.html

Google®

[k92]

http://forum.virtuemart.net/index.php?topic=140606.0
https://network.convergenceservices.in/forum/46-virtue-mart/3620-solved-vmerror-memory-limit-reached-in-model-product-getproduct.html

Google®

Thanks, I already saw those posts.

The first website recommends to display less products on a page.
I'm displaying not more than 27 products on each page.
Furthermore the error described in your link says something about memory limit. My error message is about execution time.
Moreover I'd like to know how to fix that issue. Displaying less products isn't a suitable solution for me.

The VM bug mentioned in the second url should be already fixed, right?

[GJC Web Design]

Sounds to me that your hosting/server isn't strong enough to run an ecommerce site.

I run all my clients on 512MB  on a fairly decent spec'd host

[Studio 42]

you need 512mo to have no problems.
BUt check about bad bots in your access log file, they spam websites and you can have a D.O.S.

[GJC Web Design]

BUt check about bad bots in your access log file, they spam websites and you can have a D.O.S.

Agree -- some of the sites I manage have been plagued by this recently.

Depending on the target audience I have either geo blocked offending countries, use bad bot blocker schemes in the .htaccess or if u have access fine tuned the server firewall rules

[Milbo]

you need 512mo to have no problems.
BUt check about bad bots in your access log file, they spam websites and you can have a D.O.S.

Ah come on 512? Normal browsing on a VM with for example 5000 products uses normally not more than 25 MB per page call. Of course it can increase drastically using some filter extension.
Vm needs most RAM creating the PDF, which usually takes up to 80-90 MB and so to be certain we suggest at least 128MB. And of course some administrative tasks can take a lot more RAM, for example "synchronise media", "bulk editing", etc.

And then it depends on the amount of concurrent customers how much RAM you need on your machine.