Avoid locking for upsert on pushers tables

* replace the upsert into deleted_pushers with an insert
* no need to lock for upsert on pusher_throttle

1 files changed, 16 insertions, 5 deletions

diff --git a/synapse/storage/pusher.py b/synapse/storage/pusher.py

index 19ce41fde9..3d8b4d5d5b 100644
--- a/synapse/storage/pusher.py
+++ b/synapse/storage/pusher.py
@@ -244,11 +244,19 @@ class PusherStore(SQLBaseStore):
                 "pushers",
                 {"app_id": app_id, "pushkey": pushkey, "user_name": user_id}
             )
-            self._simple_upsert_txn(
+
+            # it's possible for us to end up with duplicate rows for
+            # (app_id, pushkey, user_id) at different stream_ids, but that
+            # doesn't really matter.
+            self._simple_insert_txn(
                 txn,
-                "deleted_pushers",
-                {"app_id": app_id, "pushkey": pushkey, "user_id": user_id},
-                {"stream_id": stream_id},
+                table="deleted_pushers",
+                values={
+                    "stream_id": stream_id,
+                    "app_id": app_id,
+                    "pushkey": pushkey,
+                    "user_id": user_id,
+                },
             )
 
         with self._pushers_id_gen.get_next() as stream_id:
@@ -311,9 +319,12 @@ class PusherStore(SQLBaseStore):
 
     @defer.inlineCallbacks
     def set_throttle_params(self, pusher_id, room_id, params):
+        # no need to lock because `pusher_throttle` has a primary key on
+        # (pusher, room_id) so _simple_upsert will retry
         yield self._simple_upsert(
             "pusher_throttle",
             {"pusher": pusher_id, "room_id": room_id},
             params,
-            desc="set_throttle_params"
+            desc="set_throttle_params",
+            lock=False,
         )