Use Redis#mget for RedisCacheStore#fetch_multi

activesupport/lib/active_support/cache/redis_cache_store.rb

@@ -307,6 +307,14 @@ def read_entry(key, options = nil)
           end
         end
 
+        def read_multi_entries(names, _options)
+          if mget_capable?
+            read_multi_mget(*names)
+          else
+            super
+          end
+        end
+
         def read_multi_mget(*names)
           options = names.extract_options!
           options = merged_options(options)

activesupport/test/cache/stores/redis_cache_store_test.rb

@@ -109,6 +109,14 @@ class RedisCacheStoreCommonBehaviorTest < StoreTest
     include CacheIncrementDecrementBehavior
     include CacheInstrumentationBehavior
     include AutoloadingCacheBehavior
+
+    def test_fetch_multi_uses_redis_mget
+      assert_called(@cache.redis, :mget, returns: []) do
+        @cache.fetch_multi("a", "b", "c") do |key|
+          key * 2
+        end
+      end
+    end
   end
 
   # Separate test class so we can omit the namespace which causes expected,