Allow streaming cache invalidate all to workers. (#6749)

synapse/storage/data_stores/main/cache.py

@@ -16,6 +16,7 @@
 
 import itertools
 import logging
+from typing import Any, Iterable, Optional
 
 from twisted.internet import defer
 
@@ -43,6 +44,14 @@ class CacheInvalidationStore(SQLBaseStore):
         txn.call_after(cache_func.invalidate, keys)
         self._send_invalidation_to_replication(txn, cache_func.__name__, keys)
 
+    def _invalidate_all_cache_and_stream(self, txn, cache_func):
+        """Invalidates the entire cache and adds it to the cache stream so slaves
+        will know to invalidate their caches.
+        """
+
+        txn.call_after(cache_func.invalidate_all)
+        self._send_invalidation_to_replication(txn, cache_func.__name__, None)
+
     def _invalidate_state_caches_and_stream(self, txn, room_id, members_changed):
         """Special case invalidation of caches based on current state.
 
@@ -73,17 +82,24 @@ class CacheInvalidationStore(SQLBaseStore):
                 txn, CURRENT_STATE_CACHE_NAME, [room_id]
             )
 
-    def _send_invalidation_to_replication(self, txn, cache_name, keys):
+    def _send_invalidation_to_replication(
+        self, txn, cache_name: str, keys: Optional[Iterable[Any]]
+    ):
         """Notifies replication that given cache has been invalidated.
 
         Note that this does *not* invalidate the cache locally.
 
         Args:
             txn
-            cache_name (str)
-            keys (iterable[str])
+            cache_name
+            keys: Entry to invalidate. If None will invalidate all.
         """
 
+        if cache_name == CURRENT_STATE_CACHE_NAME and keys is None:
+            raise Exception(
+                "Can't stream invalidate all with magic current state cache"
+            )
+
         if isinstance(self.database_engine, PostgresEngine):
             # get_next() returns a context manager which is designed to wrap
             # the transaction. However, we want to only get an ID when we want
@@ -95,13 +111,16 @@ class CacheInvalidationStore(SQLBaseStore):
             txn.call_after(ctx.__exit__, None, None, None)
             txn.call_after(self.hs.get_notifier().on_new_replication_data)
 
+            if keys is not None:
+                keys = list(keys)
+
             self.db.simple_insert_txn(
                 txn,
                 table="cache_invalidation_stream",
                 values={
                     "stream_id": stream_id,
                     "cache_func": cache_name,
-                    "keys": list(keys),
+                    "keys": keys,
                     "invalidation_ts": self.clock.time_msec(),
                 },
             )