1 files changed, 1 insertions, 1 deletions

diff --git a/synapse/util/caches/ttlcache.py b/synapse/util/caches/ttlcache.py

index 99646c7cf0..6437aa907e 100644
--- a/synapse/util/caches/ttlcache.py
+++ b/synapse/util/caches/ttlcache.py
@@ -38,7 +38,7 @@ class TTLCache(object):
 
         self._timer = timer
 
-        self._metrics = register_cache("ttl", cache_name, self)
+        self._metrics = register_cache("ttl", cache_name, self, resizable=False)
 
     def set(self, key, value, ttl):
         """Add/update an entry in the cache