I would really need to ask for help. We use WPML in combination with woocommerce (shop with around 3000 products), Flatsome template, three languages for now. In the server configuration, which I think is sufficient (I am attaching a printscreen). We use the W3 Total Cache plugin to speed up the response. Even so, page loading is not optimal. The biggest problem occurs when switching to cart/checkout. The most tragic situation is when this action is performed by a registered customer. In the given combination, the switching time for incomprehensible reasons is 10-20 seconds, which is really a lot and we are losing customers. I am contacting you because we have come to the conclusion that the biggest part of the problem will be somewhere in WPML. If we leave the website running in the same configuration, we only turn off the WPML plugin, we immediately get to a maximum of one-third of the values, i.e. 5-7 seconds max. Our despair stems from the fact that nothing at all happens during the said 10-20 seconds. The browser rotates the loading icon but nothing else happens... this is very annoying for our customers. On mobile phones, the situation is even worse by a few seconds. Although we use a lot of plugins, we are generally happy with the overall speed, but the issue with the cart/checkout is driving us nuts. Thanks in advance for your help.
I will try to help identify the source of the performance problems, but to do that I would really need access to a copy of the site on a staging server if that's possible, I can't test such issues on the production site.
Are you able to make such a copy available?
I would need administrator access to the site, and permission to undergo tests, including adding some plugins for testing.
With this admin user would I be able to follow the workflow required to witness the problem (i.e. to go through the purchase steps to arrive at the checkout)?
Let me mark your next reply as private so that I can get log-in credentials from you—you may want to create a temporary admin user for us to use that you can later delete. And be sure to have a current backup of your site.
I couldn't really see a slowdown to the extent you described (10-20s to load cart/checkout pages).
When I added a product to the cart then switched to the cart it was taking about 7s, and moving to the checkout took about 8s.
I added the Query Monitor plugin to monitor the database queries, and I noticed quite a few extra queries being triggered by the Toret Zásilkovna and Toret DPD plugins, and when I disabled those the load times for the cart and checkout pages dropped to around 4-5s.
If I reactivated the Toret plugins but disabled the WPML plugins then the load times were around 5-6s.
So it's not obvious that there is a performance problem coming from WPML.
However, we will soon release WPML 4.6.9 (expected in about a week), and that includes several performance-related improvements, one of which I expect will make a modest difference to your site.
So let's keep this ticket open and upgrade to WPML 4.6.9 when it is available, and test again with that.
The updates to WPML and String Translation have been published, so I invite you to check on your site if and where you still see performance problems.
Bear in mind some incremental improvements in performance are expected with this release, but this is not the last word on the subject, and further improvements are expected in upcoming versions.
I took another look at your site, logged in, switching to the cart page, and it did indeed take around 20s.
So the first thing I checked was deactivating the 2 Toret plugins I highlighted previously that I could see when debugging were slowing down the page, and having done that the time for the server to deliver the page fell to about 4s.
