Avoid clearing cache once per language

[piotrbak]

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Describe the bug
WPML Team reported that when translating a single post we're clearing the cache once per language. It's possible to do it only once to avoid resources problems.

To Reproduce
Included in #6214 (comment)

Expected behavior
Included in #6214 (comment)

Acceptance Criteria (for WP Media team use only)

• We should launch rocket_clean_domain only once, not once per language
• No regression at clearing the translated posts
• No regression at clearing the specific languages

[zeopix]

Thanks for creating this ticket @piotrbak .

You can reproduce this issue with some simple steps:

• Create a clean WP site.
• Add WPML Plugin, register it, add few languages.
• Install WP Rocket, go to Settings > Wp Rocket > Cache > "Enable cache for logged-in wordpress users".
• In the following request, the problem already occurs.
• It can also occur when applying a translation, and many other cinrcumstances (whatever hook ends up calling rocket_clean_domain in inc/functions/files.php).

The problem is because in this method, the cache is cleared for each $url, and $url is retrieved using the function get_rocket_i18n_uri or get_rocket_i18n_home_url, which retrieves one URL per language.
This seems fine because some hooks are fired per URL, this logic seems to be correct, but later, a hook after_rocket_clean_domain is fired per URL, which is bound to clear_full_cache hook.

This later one, will do the same query on every step, so we propose to extract this hook from the foreach ( $urls as $url ) {

(Se how we tweaked this function in this gist)

An update query like this on every row of the wpv_table, repeated n times (where n=number of languages) locks this table and saturates mysql in large sites causing a significant performance impact.

[Tabrisrp]

Scope a solution ✅

We can add a new filter outside of the loop rocket_after_clean_domain, and update the hook used in the preload subscriber (Could be also good to investigate other usages of the after_rocket_clean_domain filter to see if they could be changed and reduce the number of calls to the hooked methods).

Estimate the effort ✅

Effort [S]

[CrochetFeve0251]

Seems good to me

[wordpressfan]

Small discussion: https://wp-media.slack.com/archives/CUT7FLHF1/p1698656302149819

We need to create a new action not filter exactly here:

wp-rocket/inc/functions/files.php

Line 870 in 06381b8