1 files changed, 22 insertions, 29 deletions

diff --git a/synapse/crypto/keyring.py b/synapse/crypto/keyring.py
index 04beededdc..834b107705 100644
--- a/synapse/crypto/keyring.py
+++ b/synapse/crypto/keyring.py
@@ -275,10 +275,6 @@ class Keyring(object):
         @defer.inlineCallbacks
         def do_iterations():
             with Measure(self.clock, "get_server_verify_keys"):
-                # dict[str, dict[str, VerifyKey]]: results so far.
-                # map server_name -> key_id -> VerifyKey
-                merged_results = {}
-
                 # dict[str, set(str)]: keys to fetch for each server
                 missing_keys = {}
                 for verify_request in verify_requests:
@@ -288,29 +284,29 @@ class Keyring(object):
 
                 for fn in key_fetch_fns:
                     results = yield fn(missing_keys.items())
-                    merged_results.update(results)
 
                     # We now need to figure out which verify requests we have keys
                     # for and which we don't
                     missing_keys = {}
                     requests_missing_keys = []
                     for verify_request in verify_requests:
-                        server_name = verify_request.server_name
-                        result_keys = merged_results[server_name]
-
                         if verify_request.deferred.called:
                             # We've already called this deferred, which probably
                             # means that we've already found a key for it.
                             continue
 
+                        server_name = verify_request.server_name
+
+                        # see if any of the keys we got this time are sufficient to
+                        # complete this VerifyKeyRequest.
+                        result_keys = results.get(server_name, {})
                         for key_id in verify_request.key_ids:
-                            if key_id in result_keys:
+                            key = result_keys.get(key_id)
+                            if key:
                                 with PreserveLoggingContext():
-                                    verify_request.deferred.callback((
-                                        server_name,
-                                        key_id,
-                                        result_keys[key_id],
-                                    ))
+                                    verify_request.deferred.callback(
+                                        (server_name, key_id, key)
+                                    )
                                 break
                         else:
                             # The else block is only reached if the loop above
@@ -344,27 +340,24 @@ class Keyring(object):
     @defer.inlineCallbacks
     def get_keys_from_store(self, server_name_and_key_ids):
         """
-
         Args:
-            server_name_and_key_ids (list[(str, iterable[str])]):
+            server_name_and_key_ids (iterable(Tuple[str, iterable[str]]):
                 list of (server_name, iterable[key_id]) tuples to fetch keys for
 
         Returns:
-            Deferred: resolves to dict[str, dict[str, VerifyKey]]: map from
+            Deferred: resolves to dict[str, dict[str, VerifyKey|None]]: map from
                 server_name -> key_id -> VerifyKey
         """
-        res = yield logcontext.make_deferred_yieldable(defer.gatherResults(
-            [
-                run_in_background(
-                    self.store.get_server_verify_keys,
-                    server_name, key_ids,
-                ).addCallback(lambda ks, server: (server, ks), server_name)
-                for server_name, key_ids in server_name_and_key_ids
-            ],
-            consumeErrors=True,
-        ).addErrback(unwrapFirstError))
-
-        defer.returnValue(dict(res))
+        keys_to_fetch = (
+            (server_name, key_id)
+            for server_name, key_ids in server_name_and_key_ids
+            for key_id in key_ids
+        )
+        res = yield self.store.get_server_verify_keys(keys_to_fetch)
+        keys = {}
+        for (server_name, key_id), key in res.items():
+            keys.setdefault(server_name, {})[key_id] = key
+        defer.returnValue(keys)
 
     @defer.inlineCallbacks
     def get_keys_from_perspectives(self, server_name_and_key_ids):