From 878f06f1fe0fb7027f3bb81b00ec145c94bae17a Mon Sep 17 00:00:00 2001
From: Guo Xiang Tan <gxtan1990@gmail.com>
Date: Thu, 21 May 2020 14:32:41 +0800
Subject: [PATCH] DEV: Remove custom connection reaper.

Rails 6 fixed the reaper to use one thread to reap all the connection pools.
---
 app/models/global_setting.rb          |  3 ++-
 config/application.rb                 |  5 ----
 config/initializers/099-drain_pool.rb |  4 ---
 lib/discourse.rb                      | 35 ---------------------------
 lib/freedom_patches/reaper.rb         | 20 ---------------
 5 files changed, 2 insertions(+), 65 deletions(-)
 delete mode 100644 lib/freedom_patches/reaper.rb

diff --git a/app/models/global_setting.rb b/app/models/global_setting.rb
index 21e5a137dcf..890f5ef06c6 100644
--- a/app/models/global_setting.rb
+++ b/app/models/global_setting.rb
@@ -144,8 +144,9 @@ class GlobalSetting
 
     hash["host_names"] = hostnames
     hash["database"] = db_name
-
     hash["prepared_statements"] = !!self.db_prepared_statements
+    hash["idle_timeout"] = connection_reaper_age if connection_reaper_age.present?
+    hash["reaping_frequency"] = connection_reaper_interval if connection_reaper_interval.present?
 
     { "production" => hash }
   end
diff --git a/config/application.rb b/config/application.rb
index 0157dc82895..808f9e4592b 100644
--- a/config/application.rb
+++ b/config/application.rb
@@ -360,10 +360,5 @@ module Discourse
     config.generators do |g|
       g.test_framework :rspec, fixture: false
     end
-
-    # we have a monkey_patch we need to require early... prior to connection
-    # init
-    require 'freedom_patches/reaper'
-
   end
 end
diff --git a/config/initializers/099-drain_pool.rb b/config/initializers/099-drain_pool.rb
index cff95339b8a..e69de29bb2d 100644
--- a/config/initializers/099-drain_pool.rb
+++ b/config/initializers/099-drain_pool.rb
@@ -1,4 +0,0 @@
-# frozen_string_literal: true
-
-# pg performs inconsistently with large amounts of connections
-Discourse.start_connection_reaper
diff --git a/lib/discourse.rb b/lib/discourse.rb
index 9bdbc2b3024..094ca70aec8 100644
--- a/lib/discourse.rb
+++ b/lib/discourse.rb
@@ -660,7 +660,6 @@ module Discourse
     Sidekiq.redis_pool.shutdown { |c| nil }
     # re-establish
     Sidekiq.redis = sidekiq_redis_config
-    start_connection_reaper
 
     # in case v8 was initialized we want to make sure it is nil
     PrettyText.reset_context
@@ -743,40 +742,6 @@ module Discourse
     STDERR.puts "Failed to report exception #{e} #{message}"
   end
 
-  def self.start_connection_reaper
-    return if GlobalSetting.connection_reaper_age < 1 ||
-              GlobalSetting.connection_reaper_interval < 1
-
-    # this helps keep connection counts in check
-    Thread.new do
-      while true
-        begin
-          sleep GlobalSetting.connection_reaper_interval
-          reap_connections(GlobalSetting.connection_reaper_age)
-        rescue => e
-          Discourse.warn_exception(e, message: "Error reaping connections")
-        end
-      end
-    end
-  end
-
-  def self.reap_connections(idle)
-    pools = []
-    ObjectSpace.each_object(ActiveRecord::ConnectionAdapters::ConnectionPool) { |pool| pools << pool }
-
-    pools.each do |pool|
-      # reap recovers connections that were aborted
-      # eg a thread died or a dev forgot to check it in
-      # flush removes idle connections
-      # after fork we have "deadpools" so ignore them, they have been discarded
-      # so @connections is set to nil
-      if pool.connections
-        pool.reap
-        pool.flush(idle)
-      end
-    end
-  end
-
   def self.deprecate(warning, drop_from: nil, since: nil, raise_error: false, output_in_test: false)
     location = caller_locations[1].yield_self { |l| "#{l.path}:#{l.lineno}:in \`#{l.label}\`" }
     warning = ["Deprecation notice:", warning]
diff --git a/lib/freedom_patches/reaper.rb b/lib/freedom_patches/reaper.rb
deleted file mode 100644
index dc49a528f84..00000000000
--- a/lib/freedom_patches/reaper.rb
+++ /dev/null
@@ -1,20 +0,0 @@
-# frozen_string_literal: true
-
-# Discourse ships with a connection reaper
-# this patch ensures that the connection reaper never runs in Rails
-#
-# In Rails 5.2 the connection reaper is "per-pool" this means it can bloat
-# threads quite a lot in a multisite
-#
-# Note, the "correct" way is to set this in the spec, however due to multisite
-# getting reaper_interval=0 into all the specs is not going to be trivial
-# when we eventually do that we can remove this patch
-
-if !defined? ActiveRecord::ConnectionAdapters::ConnectionPool::Reaper
-  raise "Can not find connection Reaper class, this patch will no longer work!"
-end
-
-class ActiveRecord::ConnectionAdapters::ConnectionPool::Reaper
-  def run
-  end
-end