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mastodon/app/workers/scheduler/follow_recommendations_scheduler.rb
Claire d9ae3db8d5
Improve performance of follow recommendation scheduler (#16159)
Express follow_recommendations in terms of account_summaries rather than
accounts, integrate filters that are unconditionally used, and materialize
the resulting view.

This should result in the bulk of the computation being performed only once
instead of **once per recommendation language**.
2021-05-05 22:04:52 +02:00

62 lines
1.8 KiB
Ruby

# frozen_string_literal: true
class Scheduler::FollowRecommendationsScheduler
include Sidekiq::Worker
include Redisable
sidekiq_options retry: 0
# The maximum number of accounts that can be requested in one page from the
# API is 80, and the suggestions API does not allow pagination. This number
# leaves some room for accounts being filtered during live access
SET_SIZE = 100
def perform
# Maintaining a materialized view speeds-up subsequent queries significantly
AccountSummary.refresh
FollowRecommendation.refresh
fallback_recommendations = FollowRecommendation.limit(SET_SIZE).index_by(&:account_id)
I18n.available_locales.each do |locale|
recommendations = begin
if AccountSummary.safe.filtered.localized(locale).exists? # We can skip the work if no accounts with that language exist
FollowRecommendation.localized(locale).limit(SET_SIZE).index_by(&:account_id)
else
{}
end
end
# Use language-agnostic results if there are not enough language-specific ones
missing = SET_SIZE - recommendations.keys.size
if missing.positive?
added = 0
# Avoid duplicate results
fallback_recommendations.each_value do |recommendation|
next if recommendations.key?(recommendation.account_id)
recommendations[recommendation.account_id] = recommendation
added += 1
break if added >= missing
end
end
redis.pipelined do
redis.del(key(locale))
recommendations.each_value do |recommendation|
redis.zadd(key(locale), recommendation.rank, recommendation.account_id)
end
end
end
end
private
def key(locale)
"follow_recommendations:#{locale}"
end
end