From 07a1211183894ebd62bf2c90779d30b773d35938 Mon Sep 17 00:00:00 2001
From: Daniel Waterworth <me@danielwaterworth.com>
Date: Thu, 12 Jan 2023 14:03:26 -0600
Subject: [PATCH] FIX: Prevent concurrent updates to top_topics (#19854)

to prevent lock timeouts
---
 app/models/top_topic.rb | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/app/models/top_topic.rb b/app/models/top_topic.rb
index 975adc8ec72..31fbf4efd5c 100644
--- a/app/models/top_topic.rb
+++ b/app/models/top_topic.rb
@@ -5,21 +5,25 @@ class TopTopic < ActiveRecord::Base
 
   # The top topics we want to refresh often
   def self.refresh_daily!
-    transaction do
-      remove_invisible_topics
-      add_new_visible_topics
+    DistributedMutex.synchronize("update_top_topics", validity: 5.minutes) do
+      transaction do
+        remove_invisible_topics
+        add_new_visible_topics
 
-      update_counts_and_compute_scores_for(:daily)
+        update_counts_and_compute_scores_for(:daily)
+      end
     end
   end
 
   # We don't have to refresh these as often
   def self.refresh_older!
-    older_periods = periods - %i[daily all]
+    DistributedMutex.synchronize("update_top_topics", validity: 5.minutes) do
+      older_periods = periods - %i[daily all]
 
-    transaction { older_periods.each { |period| update_counts_and_compute_scores_for(period) } }
+      transaction { older_periods.each { |period| update_counts_and_compute_scores_for(period) } }
 
-    compute_top_score_for(:all)
+      compute_top_score_for(:all)
+    end
   end
 
   def self.refresh!