David

I have taken several steps to resolve this issue, including reaching out through Facebook support and creating a staging site to demonstrate the problem. Despite my efforts and clear demonstration of the issue, the support team has ultimately decided not to address this incompatibility. The ticket was closed with no resolution, leaving the problem unaddressed.

Community Warning: I feel it’s my responsibility to warn others in the community about this incompatibility. If you’re considering using?Checkout Field Manager alongside the WooCommerce PayPal Payments plugin, please be aware that you might encounter this issue on mobile devices. My experience has shown that while the issue is clear, support may not be willing or able to provide a fix.

Hi @qtwrk ,

I checked it with the server support, redis mem limit is set to 16GB on our server, so 4.4 GB should still be ok. I also tried your proposal and disabled Redis in LiteSpeed temorarily but the issue still occured. Just with a new error message:

PHP Fatal error:  Uncaught TypeError: call_user_func_array(): Argument #1 ($callback) must be a valid callback, class "LiteSpeed\Thirdparty\Aelia_CurrencySwitcher" not found in /var/www/vhosts/example.com/httpdocs/wp-includes/class-wp-hook.php:324

Stack trace:
#0 /var/www/vhosts/example.com/httpdocs/wp-includes/class-wp-hook.php(348): WP_Hook->apply_filters()
#1 /var/www/vhosts/example.com/httpdocs/wp-includes/plugin.php(517): WP_Hook->do_action()
#2 /var/www/vhosts/example.com/httpdocs/wp-content/plugins/litespeed-cache/src/core.cls.php(379): do_action()
#3 /var/www/vhosts/example.com/httpdocs/wp-includes/class-wp-hook.php(324): LiteSpeed\Core->load_thirdparty()
#4 /var/www/vhosts/example.com/httpdocs/wp-includes/class-wp-hook.php(348): WP_Hook->apply_filters()
#5 /var/www/vhosts/example.com/httpdocs/wp-includes/plugin.php(517): WP_Hook->do_action()
#6 /var/www/vhosts/example.com/httpdocs/wp-settings.php(665): do_action()
#7 /var/www/vhosts/example.com/httpdocs/wp-config.php(96): require_once('...')
#8 /var/www/vhosts/example.com/httpdocs/wp-load.php(50): require_once('...')
#9 /var/www/vhosts/example.com/httpdocs/wp-blog-header.php(13): require_once('...')
#10 /var/www/vhosts/example.com/httpdocs/index.php(17): require('...')
#11 {main}
  thrown in /var/www/vhosts/example.com/httpdocs/wp-includes/class-wp-hook.php on line 324

PHP Fatal error:  Uncaught Error: Class "LiteSpeed\Utility" not found in /var/www/vhosts/example.com/httpdocs/wp-content/plugins/litespeed-cache/src/control.cls.php:637

Stack trace:
#0 /var/www/vhosts/example.com/httpdocs/wp-content/plugins/litespeed-cache/src/core.cls.php(572): LiteSpeed\Control->finalize()
#1 /var/www/vhosts/example.com/httpdocs/wp-content/plugins/litespeed-cache/src/core.cls.php(487): LiteSpeed\Core->send_headers()
#2 [internal function]: LiteSpeed\Core->send_headers_force()
#3 {main}
  thrown in /var/www/vhosts/example.com/httpdocs/wp-content/plugins/litespeed-cache/src/control.cls.php on line 637

PHP Fatal error:  Uncaught Error: Class "LiteSpeed\File" not found in /var/www/vhosts/example.com/httpdocs/wp-content/plugins/litespeed-cache/src/core.cls.php:437

Stack trace:
#0 /var/www/vhosts/example.com/httpdocs/wp-content/plugins/litespeed-cache/src/core.cls.php(569): LiteSpeed\Core->_check_is_html()
#1 /var/www/vhosts/example.com/httpdocs/wp-includes/class-wp-hook.php(324): LiteSpeed\Core->send_headers()
#2 /var/www/vhosts/example.com/httpdocs/wp-includes/class-wp-hook.php(348): WP_Hook->apply_filters()
#3 /var/www/vhosts/example.com/httpdocs/wp-includes/plugin.php(517): WP_Hook->do_action()
#4 /var/www/vhosts/example.com/httpdocs/wp-includes/load.php(1260): do_action()
#5 [internal function]: shutdown_action_hook()
#6 {main}
  thrown in /var/www/vhosts/example.com/httpdocs/wp-content/plugins/litespeed-cache/src/core.cls.php on line 437

Any other idea what could cause this?
Thank you.

Hello Pedro (@petredobrescu),

Firstly, I’d like to extend my sincere thanks for your immediate and comprehensive response!

I have one follow-up question regarding a specific issue I’ve encountered with the plugin settings. When I try to exclude certain thumbnail sizes by unchecking them in the plugin settings and then save the changes, the checkboxes automatically revert to their previous state, effectively not saving my preferences. This issue persists even after multiple attempts with different browsers.

Could this be a known issue or something specific to my setup?

Thank you once again.
David

Hi @bisratlearn

Please pass this topic on to the developers and please don’t just paste this standard ChatGPT answer everywhere, thanks

After switching from

High-performance order storage (recommended)

to

WordPress posts storage (legacy)

the error disappeard. However, it would be good if this update would be compatible with the new tables as well.

Hi @qtwrk,

Thank you for your response. I added the logging as you mentioned and received the following during today’s incident:

LiteSpeed Cache Warning: Undefined $res. Key – 24ac5options.alloptions, Data – a:1:{s:4:”data”;a:1167:{s:20:” … Here a huge block of data continues, followed by about 1500 lines of website html. Unfortunately it did not track any Expire.

Apart from that, it was recorded much better today how the error builds up from the warning message to a critical error. This is the sequence of events from the log. If you could provide me with further assistance based on this, I would be very grateful.

LiteSpeed Cache Warning: Undefined $res. Key - 24ac5options.alloptions, Data ...

PHP Warning: Undefined variable $res in /var/www/vhosts/example.com/httpdocs/wp-content/plugins/litespeed-cache/src/object-cache.cls.php on line 490

PHP Notice: Redis::setex(): send of 8192 bytes failed with errno=11 Resource temporarily unavailable in /var/www/vhosts/example.com/httpdocs/wp-content/plugins/litespeed-cache/src/object-cache.cls.php

PHP Notice: Redis::setex(): Send of 4410762 bytes failed with errno=11 Resource temporarily unavailable in /var/www/vhosts/example.com/httpdocs/wp-content/plugins/litespeed-cache/src/object-cache.cls.php on line 470
...

Undefined variable $res in /var/www/vhosts/example.com/httpdocs/wp-content/plugins/litespeed-cache/src/object-cache.cls.php on line 490

PHP Fatal error: Uncaught RedisException: read error on connection to localhost:6379 in /var/www/vhosts/example.com/httpdocs/wp-content/plugins/litespeed-cache/src/object-cache.cls.php:434 Stack trace: #0 /var/www/vhosts/example.com/httpdocs/wp-content/plugins/litespeed-cache/src/object-cache.cls.php(434): Redis->get() #1 /var/www/vhosts/example.com/httpdocs/wp-content/plugins/litespeed-cache/src/object.lib.php(777): LiteSpeed\Object_Cache->get() #2 /var/www/vhosts/example.com/httpdocs/wp-content/plugins/litespeed-cache/src/object.lib.php(160): WP_Object_Cache->get() #3 /var/www/vhosts/example.com/httpdocs/wp-includes/option.php(599): wp_cache_get() #4 /var/www/vhosts/example.com/httpdocs/wp-includes/option.php(845): wp_load_alloptions() #5 /var/www/vhosts/example.com/httpdocs/wp-includes/cron.php(1242): update_option() #6 /var/www/vhosts/example.com/httpdocs/wp-includes/cron.php(523): _set_cron_array() #7 /var/www/vhosts/example.com/httpdocs/wp-cron.php(156): wp_ in /var/www/vhosts/example.com/httpdocs/wp-content/plugins/litespeed-cache/src/object-cache.cls.php on line 434

Hi @joostvandevijver,

Thank you for your immediate response. I did some testing and figured out that this issue is indeed created from a different plugin. It is caused by the WooCommerce Checkout Manager plugin from QuadLayers. I will reach out to them for a fix.

Thank you for your help!

Hi @qtwrk

Thank you for your response.

I further analysed this issue. While the warning about the undefined $res variable is consistent, I’ve observed a couple of other errors occurring around the time of the memory spikes:

The first is related to Wordfence:

PHP Fatal error: Uncaught Error: Class "WordfenceLS\Controller_DB" not found in /var/www/vhosts/example.com/httpdocs/wp-content/plugins/wordfence/modules/login-security/classes/model/settings/db.php:73

This error suggests there might be a compatibility issue with Wordfence, specifically with the login security module.

Another error I encountered is related to a third-party integration with LiteSpeed:

PHP Fatal error: Uncaught TypeError: call_user_func_array(): Argument #1 ($callback) must be a valid callback, class "LiteSpeed\Thirdparty\Aelia_CurrencySwitcher" not found in /var/www/vhosts/example.com/httpdocs/wp-includes/class-wp-hook.php:310

To answer your questions:

• The issue has occurred several times, and I have not tried disabling the object cache due to its importance for my site’s performance.
• Regarding the debug log code before the undefined $res warning, I have not noticed any logs indicating the value it tries to set. If there’s a specific logging method or level you recommend, I can certainly implement it to gather more detailed information during these events.

Based on these additional errors, it does seem like there could be a compatibility issue at play. Any further insights or assistance you can provide would be greatly appreciated.

Additionally, I have two follow-up questions that could help me

1. Is there a way to limit the memory consumption of the LiteSpeed Cache plugin directly? If a setting or a tweak could prevent the plugin from using a certain amount of memory, it would be a great interim solution.
2. Does LiteSpeed Cache have a feature to automatically flush all caches if a certain memory usage threshold is hit? An automatic cache purging mechanism under specific conditions might prevent the server from reaching a critical state

Thank you for your help.

Hi @stevejburge

All right, I see. Nevertheless, something is now missing on this page. It should be directly clear how many elements exist and additionally how many will be deleted. For example tags of a custom post type. Currently this is a complete blind flight. How many are affected? Do I delete 1.000, 10.000 or 100.000 with my selection? That makes a big difference e.g. if it leads to a server timeout or not.

Hi @stevejburge

Thanks for getting back to me so quickly. I just actiated the previous version in order to see whats missing and it looks like the complete left section is missing now. I will attach you before and after screenshots.
Before: https://imgur.com/a/0LXrkDV
Now: https://imgur.com/a/gpV4w2S

Thanks for checking this!

Hi @qtwrk

Thank you, it finally removed the message. And its not an issue that I don’t use the default _lscache_vary in that field anymore?

Hi @qtwrk

report number is FZATUYBA. Its a single site. Thanks for looking into this.

Since Litespeed pulls up this message it should know what’s happening. It would be interesting to know how and when it detects this error. When I ping redis it’s up and running.

Hi @qtwrk

Thank you for your response. I tried but can’t catch the problem in the log files.

When it occurs, the only option is to disable the Litespeed plugin and restart the server completely. Restarting the server while LiteSpeed plugin is active is not enough. Only when it is disabled and the backend of the website shows “Can NOT find LSCWP path for object cache initialization in /var/www/vhosts/example.com/httpdocs/wp-content/object-cache.php”, the website becomes accessible again.

Then I have to delete the complete Litespeed Cache Folder under /var/www/vhosts/lscache
After that I can activate the plugin again and everything works normal again for the next 1-2 weeks.

Is there any way to limit the requests it can send?

Hi @qtwrk

Thank you for the detailed screenshots and your help!

Regarding the first option, unfortunately LiteSpeed is not visible on the admin bar even in landscape mode, maybe my screen is just too narrow.

However the second option with Toolbox worked perfectly. I didn’t find it because I was looking at LiteSpeed under the Settings menu all the time and there is no option there.