Automatically clear entity cache after save/update?

[laryn]

Description of the bug

I've noticed in a variety of contexts that it takes a long time for changes to register after adding or updating nodes, comments, etc. and I believe this is due to entity cache being added to core.

One example that was fixed in contrib was here, in webform civicrm:

• backdrop-contrib/webform_civicrm@4ee1eec

I'm also working with a site that has reported that nobody's replies are showing up in a forum, which turned out to be a cache issue. I've added cache_clear_all($comment->cid, 'cache_entity_comment'); in a hook_comment_insert() and hook_comment_update() but I'm wondering if we should clear the targeted entity cache immediately in core after saving or updating.

[philsward]

I feel like the suggestion is the "expected" workflow, however...

Two thoughts:

1. Smaller, low traffic sites, this workflow will be fine.

2. Larger, high traffic sites, this might cause strain on the webserver and database, impacting performance.

I unfortunately don't have any suggestion for #2 other than a contrib giving explicit control over the workflow.

[indigoxela]

Cache invalidation can be tricky. Clearing the whole cache doesn't seem the right approach, though. We should rather clear the specific caches, that are affected by a comment addition (or edit). Which ones?

Adding a comment might also affect a specific node and page cache entry - is that correct?

[laryn]

I think the command I listed will only clear a specific comment's cache, not all caches. It seems to be working in a module that I'm testing with.

cache_clear_all($comment->cid, 'cache_entity_comment');