1 files changed, 22 insertions, 7 deletions
diff --git a/synapse/storage/databases/main/cache.py b/synapse/storage/databases/main/cache.py
index 12e9a42382..efe9f3ad88 100644
--- a/synapse/storage/databases/main/cache.py
+++ b/synapse/storage/databases/main/cache.py
@@ -33,7 +33,7 @@ from synapse.storage.database import (
 )
 from synapse.storage.engines import PostgresEngine
 from synapse.storage.util.id_generators import MultiWriterIdGenerator
-from synapse.util.caches.descriptors import _CachedFunction
+from synapse.util.caches.descriptors import CachedFunction
 from synapse.util.iterutils import batch_iter
 
 if TYPE_CHECKING:
@@ -91,6 +91,11 @@ class CacheInvalidationWorkerStore(SQLBaseStore):
         else:
             self._cache_id_gen = None
 
+        self.external_cached_functions = {}
+
+    def register_external_cached_function(self, cache_name, func):
+        self.external_cached_functions[cache_name] = func
+
     async def get_all_updated_caches(
         self, instance_name: str, last_id: int, current_id: int, limit: int
     ) -> Tuple[List[Tuple[int, tuple]], int, bool]:
@@ -178,7 +183,11 @@ class CacheInvalidationWorkerStore(SQLBaseStore):
                     members_changed = set(row.keys[1:])
                     self._invalidate_state_caches(room_id, members_changed)
                 else:
-                    self._attempt_to_invalidate_cache(row.cache_func, row.keys)
+                    res = self._attempt_to_invalidate_cache(row.cache_func, row.keys)
+                    if not res:
+                        external_func = self.external_cached_functions[row.cache_func]
+                        if external_func:
+                            external_func.invalidate(row.keys)
 
         super().process_replication_rows(stream_name, instance_name, token, rows)
 
@@ -269,9 +278,7 @@ class CacheInvalidationWorkerStore(SQLBaseStore):
             return
 
         cache_func.invalidate(keys)
-        await self.db_pool.runInteraction(
-            "invalidate_cache_and_stream",
-            self._send_invalidation_to_replication,
+        await self.send_invalidation_to_replication(
             cache_func.__name__,
             keys,
         )
@@ -279,7 +286,7 @@ class CacheInvalidationWorkerStore(SQLBaseStore):
     def _invalidate_cache_and_stream(
         self,
         txn: LoggingTransaction,
-        cache_func: _CachedFunction,
+        cache_func: CachedFunction,
         keys: Tuple[Any, ...],
     ) -> None:
         """Invalidates the cache and adds it to the cache stream so slaves
@@ -293,7 +300,7 @@ class CacheInvalidationWorkerStore(SQLBaseStore):
         self._send_invalidation_to_replication(txn, cache_func.__name__, keys)
 
     def _invalidate_all_cache_and_stream(
-        self, txn: LoggingTransaction, cache_func: _CachedFunction
+        self, txn: LoggingTransaction, cache_func: CachedFunction
     ) -> None:
         """Invalidates the entire cache and adds it to the cache stream so slaves
         will know to invalidate their caches.
@@ -334,6 +341,14 @@ class CacheInvalidationWorkerStore(SQLBaseStore):
                 txn, CURRENT_STATE_CACHE_NAME, [room_id]
             )
 
+    async def send_invalidation_to_replication(self, cache_name, keys):
+        await self.db_pool.runInteraction(
+            "send_invalidation_to_replication",
+            self._send_invalidation_to_replication,
+            cache_name,
+            keys,
+        )
+
     def _send_invalidation_to_replication(
         self, txn: LoggingTransaction, cache_name: str, keys: Optional[Iterable[Any]]
     ) -> None: