Merge branch 'sh-cache-table-exists' into 'master'

Cache table_exists?('application_settings') to reduce repeated schema reloads

Closes #43355

See merge request gitlab-org/gitlab-ce!17781

2 files changed, 6 insertions, 1 deletions

diff --git a/lib/gitlab/current_settings.rb b/lib/gitlab/current_settings.rb
index b7c596a973d..e392a015b91 100644
--- a/lib/gitlab/current_settings.rb
+++ b/lib/gitlab/current_settings.rb
@@ -70,7 +70,7 @@ module Gitlab
         active_db_connection = ActiveRecord::Base.connection.active? rescue false
 
         active_db_connection &&
-          ActiveRecord::Base.connection.table_exists?('application_settings')
+          Gitlab::Database.cached_table_exists?('application_settings')
       rescue ActiveRecord::NoDatabaseError
         false
       end
diff --git a/lib/gitlab/database.rb b/lib/gitlab/database.rb
index d4fc69cb173..76501dd50e8 100644
--- a/lib/gitlab/database.rb
+++ b/lib/gitlab/database.rb
@@ -187,6 +187,11 @@ module Gitlab
       connection.schema_cache.columns_hash(table_name).has_key?(column_name.to_s)
     end
 
+    def self.cached_table_exists?(table_name)
+      # Rails 5 uses data_source_exists? instead of table_exists?
+      connection.schema_cache.table_exists?(table_name)
+    end
+
     private_class_method :connection
 
     def self.database_version