Invalidate query cache for all connections in the current thread

This change ensures that all query cahces are cleared across all
connections per handler for the current thread so if you write on one
connection the read will have the query cache cleared.

1 files changed, 38 insertions, 0 deletions

diff --git a/activerecord/test/cases/query_cache_test.rb b/activerecord/test/cases/query_cache_test.rb
index 04bbc7d136..eb32b690aa 100644
--- a/activerecord/test/cases/query_cache_test.rb
+++ b/activerecord/test/cases/query_cache_test.rb
@@ -502,6 +502,44 @@ class QueryCacheTest < ActiveRecord::TestCase
     }.call({})
   end
 
+  def test_clear_query_cache_is_called_on_all_connections
+    skip "with in memory db, reading role won't be able to see database on writing role" if in_memory_db?
+    with_temporary_connection_pool do
+      ActiveRecord::Base.connection_handlers = {
+        writing: ActiveRecord::Base.default_connection_handler,
+        reading: ActiveRecord::ConnectionAdapters::ConnectionHandler.new
+      }
+
+      ActiveRecord::Base.connected_to(role: :reading) do
+        ActiveRecord::Base.establish_connection(ActiveRecord::Base.configurations["arunit"])
+      end
+
+      mw = middleware { |env|
+        ActiveRecord::Base.connected_to(role: :reading) do
+          @topic = Topic.first
+        end
+
+        assert @topic
+
+        ActiveRecord::Base.connected_to(role: :writing) do
+          @topic.title = "It doesn't have to be crazy at work"
+          @topic.save!
+        end
+
+        assert_equal "It doesn't have to be crazy at work", @topic.title
+
+        ActiveRecord::Base.connected_to(role: :reading) do
+          @topic = Topic.first
+          assert_equal "It doesn't have to be crazy at work", @topic.title
+        end
+      }
+
+      mw.call({})
+    end
+  ensure
+    ActiveRecord::Base.connection_handlers = { writing: ActiveRecord::Base.default_connection_handler }
+  end
+
   private
 
     def with_temporary_connection_pool