Change 715235 had a related patch set uploaded (by Kosta Harlan; author: Kosta Harlan):

[mediawiki/extensions/GrowthExperiments@master] AddLinkSubmissionHandler: Use getByLinkTarget and add logging

https://gerrit.wikimedia.org/r/715235

We could potentially make use of a cache with a TTL of something like 6 hours (long enough to ensure that the job queue had a chance to run and that the search index could have been updated from the onSearchDataForIndex hook). We would add page IDs to the cache when an article is edited and it has link recommendations associated with it; then 1) in BeforePageDisplayHook or in the recommendation provider, we would ensure that we don't include page titles from that cached list, which would prevent the Add Link UX from loading in the scenario described in the description of this phab task and 2) SearchTaskSuggester::filter() could exclude items from the cached list, to prevent those articles from appearing in the scenario described in T290315: Add Link: Ensure user does not see invalid tasks in task queue

Discovery-Search team, we currently have some logic in HomepageHooks::onSearchDataForIndex where we do:

$fields[WeightedTagsHooks::FIELD_NAME][] = LinkRecommendationTaskTypeHandler::WEIGHTED_TAG_PREFIX
				. '/' . CirrusIndexField::MULTILIST_DELETE_GROUPING;
			try {
				$this->linkRecommendationHelper->deleteLinkRecommendation(
					$page->getTitle()->toPageIdentity(), false );
			} catch ( DBReadOnlyError $e ) {
				// Leaving a dangling DB row behind doesn't cause any problems so just ignore this.
			}

The idea is that we remove a cached link recommendation entry from the local database and also tell ElasticSearch to update the article's hasrecommendation field in the search index. We want this to happen as soon as possible after any type of edit to an article containing link recommendations, since those articles should not be presented to the user (the link recommendations might be invalidated by the edit made to the article).

As seen in the task description, there can be a considerable lag after an edit happens to the article and before the search index is updated, and before the cached item is dropped from the database.

So, we were wondering if it would be problematic to issue deletes to CirrusSearch from the PageSaveComplete hook? Example code we use elsewhere:

$cirrusSearch = ( $this->cirrusSearchFactory )();
			$cirrusSearch->resetWeightedTags( $pageIdentity,
				LinkRecommendationTaskTypeHandler::WEIGHTED_TAG_PREFIX );

Would that result in faster updates to the search index or would there still be some lag as those updates are processed?