1 files changed, 8 insertions, 0 deletions
diff --git a/activerecord/lib/active_record/connection_adapters/schema_cache.rb b/activerecord/lib/active_record/connection_adapters/schema_cache.rb
index 37ff4e4613..981d5d7a3c 100644
--- a/activerecord/lib/active_record/connection_adapters/schema_cache.rb
+++ b/activerecord/lib/active_record/connection_adapters/schema_cache.rb
@@ -13,6 +13,14 @@ module ActiveRecord
         @tables       = {}
       end
 
+      def initialize_dup(other)
+        super
+        @columns      = @columns.dup
+        @columns_hash = @columns_hash.dup
+        @primary_keys = @primary_keys.dup
+        @tables       = @tables.dup
+      end
+
       def primary_keys(table_name)
         @primary_keys[table_name] ||= table_exists?(table_name) ? connection.primary_key(table_name) : nil
       end