perf(hybridcloud): Skip correlated subqueries in user.serialize_many

src/sentry/hybridcloud/rpc/filter_query.py

@@ -109,6 +109,7 @@ def serialize_many(
         as_user: RpcUser | None = None,
         auth_context: AuthenticationContext | None = None,
         serializer: SERIALIZER_ENUM | None = None,
+        select_related: bool = True,
     ) -> list[OpaqueSerializedResponse]:
         from sentry.api.serializers import serialize
         from sentry.users.services.user import RpcUser
@@ -121,7 +122,7 @@ def serialize_many(
         if as_user is None and auth_context:
             as_user = auth_context.user
 
-        result = self.query_many(filter=filter)
+        result = self.query_many(filter=filter, select_related=select_related)
         return serialize(
             list(result),
             user=as_user,

src/sentry/users/services/user/impl.py

@@ -62,7 +62,9 @@ def serialize_many(
         auth_context: AuthenticationContext | None = None,
         serializer: UserSerializeType | None = None,
     ) -> list[OpaqueSerializedResponse]:
-        return self._FQ.serialize_many(filter, as_user, auth_context, serializer)
+        return self._FQ.serialize_many(
+            filter, as_user, auth_context, serializer, select_related=False
+        )
 
     def get_many(self, *, filter: UserFilterArgs) -> list[RpcUser]:
         return self._FQ.get_many(filter)

tests/sentry/users/services/test_user.py

@@ -1,3 +1,6 @@
+from django.db import connections
+from django.test.utils import CaptureQueriesContext
+
 from sentry.silo.base import SiloMode
 from sentry.testutils.cases import TestCase
 from sentry.testutils.silo import all_silo_test, assume_test_silo_mode
@@ -74,6 +77,19 @@ def test_add_permission(self) -> None:
         created = user_service.add_permission(user_id=self.user.id, permission="superuser.write")
         assert created is False
 
+    def test_serialize_many_avoids_correlated_subqueries(self) -> None:
+        """base_query() eagerly loads data via correlated subqueries for the
+        get_many/serialize_rpc path. serialize_many should not pay for these
+        since the API serializer re-fetches what it needs in get_attrs()."""
+        with assume_test_silo_mode(SiloMode.CONTROL):
+            user_service.serialize_many(filter={"user_ids": [self.user.id]})
+
+            with CaptureQueriesContext(connections["control"]) as ctx:
+                user_service.serialize_many(filter={"user_ids": [self.user.id]})
+
+            all_sql = " ".join(q["sql"] for q in ctx.captured_queries)
+            assert "array_agg" not in all_sql
+
     def test_remove_permission(self) -> None:
         # Create a permission first
         with assume_test_silo_mode(SiloMode.CONTROL):