Prevent `table_comment` query if a table doesn't have a comment

2 files changed, 13 insertions, 3 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
index 718a6c5b91..41c6b2d9bd 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
@@ -542,7 +542,9 @@ module ActiveRecord
         end
       end
 
-      def table_options(table_name)
+      def table_options(table_name) # :nodoc:
+        table_options = {}
+
         create_table_info = create_table_info(table_name)
 
         # strip create_definitions and partition_options
@@ -551,10 +553,14 @@ module ActiveRecord
         # strip AUTO_INCREMENT
         raw_table_options.sub!(/(ENGINE=\w+)(?: AUTO_INCREMENT=\d+)/, '\1')
 
+        table_options[:options] = raw_table_options
+
         # strip COMMENT
-        raw_table_options.sub!(/ COMMENT='.+'/, '')
+        if raw_table_options.sub!(/ COMMENT='.+'/, '')
+          table_options[:comment] = table_comment(table_name)
+        end
 
-        raw_table_options
+        table_options
       end
 
       # Maps logical Rails types to MySQL-specific data types.
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
index 6318b1c65a..4a7a166e5b 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
@@ -238,6 +238,10 @@ module ActiveRecord
           PostgreSQLColumn.new(*args)
         end
 
+        def table_options(table_name) # :nodoc:
+          { comment: table_comment(table_name) }
+        end
+
         # Returns a comment stored in database for given table
         def table_comment(table_name) # :nodoc:
           name = Utils.extract_schema_qualified_name(table_name.to_s)