Conflict with SG Optimizer

Can confirm that I am also facing the exact same issue on my website. Pages weren’t being cached using the Dynamic Caching feature on SG Optimizer and after disabling the “Yith WooCommerce Wishlist” plugin and another plugin “WooCommerce Multi Currency by Villa Theme”, the caching started working as intended again. After reaching out to SiteGround’s support, this is what they said:

It looks like something on your site is initiating a session on the home page. Thus, our plugin does not cache the data to avoid possible security issues such as viewing the private session information of a different visitor due to cache. You may want to review the settings of your scripts and plugins and to consult the developers of the software you are using for this purpose (most likely the various Woocommerce plugins). They may be able to advise on how to avoid creating such sessions in a way which is incompatible with dynamic cache.

Apart from this, after disabling the YITH WooCommerce plugin, I tested my website on GTMetrix and the loading speed improved by ~3 seconds.. Which is a big improvement in my opinion, from just disabling one plugin. Page loads in under 4 seconds now.

• This reply was modified 3 years, 9 months ago by Selah.

Hi there

First of all, thank you for your report

I’m not sure why this is happening just now, since session system has been the same since version 3.x of wishlist
My best guess is that something suddnely changed with their algorythm, and as such it is difficult to prevent this kind of problems in the future

Session cookie is registered in order to store unique ID for current guest user; that ID is then required in order to identify wishlists that are related to current session
As you can see, in order to keep wishlist functional for guest users, there is little that we can do but create a cookie

What we can do to help you prevent performance issues, is to review plugin code, and postpone cookie creation till the very moment user requests to add something to wishlist
I’ll do some testing and update you on this thread about my conclusions

Hi again

I performed some testing on the plugin, and I found out that the very fact of checking if a product is in wishlist, was creating a new session for the guest users
Given that session requires a dedicated cookie, this prevented cache from applying to any page, creating performance issues for any non-logged user

For this reason I reviewed the plugin code, and prevented session creation, at least until user doesn’t interact directly with the wishlist (adds a product to the list)

We’re still performing tests over these changes, but if everything goes as expected, next minor version will contain this patch
I’ll keep you posted on updates

Though I am not the one that started the thread, thanks for the update on this.

Also my thanks @yithemes!

Hi guys

Just a quick update on this topic; version 3.0.21 is now out with a fix to the problem that you reported

Fix: avoid setting session_id, until guest performs any edit operation over the lists

Thanks again for letting us know

Thanks very much!