[Closed] Severe performance regression after updating WPML — DB CPU spikes & resource usage ~2x

Hi Mikheil,

I just wanted to inform you that our 2nd-tier support spent some time on this and we have the points below:

- The tool you provided to us does not allow to index specific post, and it works for the whole website that takes a long time for us and it did not provide the information that could be helpfull.

- 2nd tier found out that by commenting out the code below:

if( QFIP_SLT_licence::verify_wwt_domain() ) {
	define( 'QFIP_APP_API_URL', '<em><u>hidden link</u></em>');
}
else {
	define( 'QFIP_APP_API_URL', '<em><u>hidden link</u></em>');
}

On this plugin file:

/wp-content/plugins/quick-featured-images-pro/quick-featured-images-pro.php

It boosts the performance significantly.

There was another point regarding WPML SEO plugin impact that is reported to the development team.

Making improvements there will take time as the dev team need to work on that and make sure it will be considered as an official release.

Thanks.

Hello,

sharing some more updates from our side:

Try limiting the posts that are queried per sitemap chunk.

This can be limited by:

/* Limit the number of sitemap entries for Yoast SEO */
function max_entries_per_sitemap() {
    return 100;
}

add_filter( 'wpseo_sitemap_entries_per_page', 'max_entries_per_sitemap' );

as per their documentation: hidden link

This will create MORE sitemaps, but the queries that are going to be done will be less expensive per sitemap chunk and in fact less CPU usage.

If you prefer optimizing the sitemap instead, you can disable the feature by adding define( 'WPML_SEO_ENABLE_SITEMAP_HREFLANG', false ); in the wp-config.php file.

In parallel, re-activate the HREFLANG in the HEAD.

https://wpml.org/documentation/plugins-compatibility/using-wordpress-seo-with-wpml/#:~:text=each%20language).-,Using%20Hreflang%20Tags,-By%20default%2C%20WPML

let me know how it goes.

Regards,
Drazen

Hello,

1) I would advise installing older version of WPML, but you can find it under downloads under changelog:

- https://wpml.org/download/wpml-multilingual-cms/?section=changelog
- https://wpml.org/download/wpml-string-translation/?section=changelog

2) Were you able to try and check our suggestion shared? Did that help?

Please let us know.

Regards,
Drazen

Hello,

thanks, yes Christopher has updated our escalated ticket and team with communication over the email. He should have already updated you also with new approach from side that we are checking and discussing.

If you prefer you can continue and keep communication inside this ticket or via email.

We will update you when we have somew news to share

Regards,
Drazen

Hi Mikheil,

Our team finished checking and here’s a short summary of what we’ve found so far:

- Comparing WPML 4.6.15 and 4.8.1 showed no significant difference in performance — query counts, execution time, memory usage, and total request times are nearly identical.

- The main performance issues seem to come from cron jobs triggered by the Yoast SEO and Internal Link Juicer plugins. Both have custom WPML integration code and generate a high number of SQL queries during background processing.

The Internal Link Juicer plugin, in particular, has more than 47,000 pending cron jobs, which are quite CPU- and memory-intensive. These background tasks are processed slowly and repeatedly run heavy database queries, which explains the CPU, memory, and disk usage spikes you observed.

Two queries stand out as the most resource-heavy:

- One from Yoast SEO, repeatedly running translation lookups.

- One from Internal Link Juicer, loading around 770,000 rows from the icl_translations table into memory.

To verify whether these cron jobs are the real source of the problem, we can offer to disable cron jobs for some time and monitoring the performance:

define('DISABLE_WP_CRON', true);

If the issue disappears after disabling cron, it will confirm that these jobs are responsible for the resource spikes. In that case, we’ll send the full report with exact logs of the slow queries and details on what needs to be optimized to permanently fix the issue.

Let us know please your reply.

Regards,
Dražen

Hello,

I will share your reply with our team and ask to recheck again and see if anything we have missed or that might be related to with those crons and different WPML versions.

I will update when I have some news.

Regards,
Drazen

Hello,

we have created a custom package that is available here:
hidden link

Please try next steps to test following related queries:

1. Concurrent UPDATE queries caused by admin notices. Install a package and find out if it solves issues with CPU spikes. If it will work out no need to test step 2.
2. Big selects in cron jobs by 'Internal Links Juicer' plugin. Add temporarily define('DISABLE_WP_CRON', true); to the config file and find out if it improves CPU usage.

Let us know how it goes.

Regards,
Drazen