ref(crons): Fix N+1 query in MonitorSerializer by removing is_muted property (#103693)

Removes the computed property Monitor.is_muted and replaces it with a
standalone is_monitor_muted(monitor) function for better clarity and 
to fix an N+1 query issue in MonitorSerializer.

The serializer now efficiently computes mute status for multiple
monitors in a single pass by checking if any environment is unmuted, 
rather than calling the property on each monitor individually which
would trigger separate queries.

Author: evanpurkhiser

src/sentry/monitors/models.py

@@ -325,7 +325,7 @@ def get_audit_log_data(self):
             "name": self.name,
             "status": self.status,
             "config": self.config,
-            "is_muted": self.is_muted,
+            "is_muted": is_monitor_muted(self),
             "slug": self.slug,
             "owner_user_id": self.owner_user_id,
             "owner_team_id": self.owner_team_id,
@@ -433,22 +433,22 @@ def normalize_before_relocation_import(
         self.guid = uuid4()
         return old_pk
 
-    @property
-    def is_muted(self) -> bool:
-        """
-        A monitor is considered muted if ALL of its environments are muted.
-        If a monitor has no environments, it is considered unmuted.
-        """
-        env_counts = MonitorEnvironment.objects.filter(monitor_id=self.id).aggregate(
-            total=models.Count("id"), muted=models.Count("id", filter=Q(is_muted=True))
-        )
 
-        # If no environments exist, monitor is not muted
-        if env_counts["total"] == 0:
-            return False
+def is_monitor_muted(monitor: Monitor) -> bool:
+    """
+    A monitor is considered muted if ALL of its environments are muted.
+    If a monitor has no environments, it is considered unmuted.
+    """
+    env_counts = MonitorEnvironment.objects.filter(monitor_id=monitor.id).aggregate(
+        total=models.Count("id"), muted=models.Count("id", filter=Q(is_muted=True))
+    )
+
+    # If no environments exist, monitor is not muted
+    if env_counts["total"] == 0:
+        return False
 
-        # Monitor is muted only if ALL environments are muted
-        return env_counts["total"] == env_counts["muted"]
+    # Monitor is muted only if ALL environments are muted
+    return env_counts["total"] == env_counts["muted"]
 
 
 def check_organization_monitor_limit(organization_id: int) -> None:
@@ -637,7 +637,7 @@ def ensure_environment(
         monitor_env, created = MonitorEnvironment.objects.get_or_create(
             monitor=monitor,
             environment_id=environment.id,
-            defaults={"status": MonitorStatus.ACTIVE, "is_muted": monitor.is_muted},
+            defaults={"status": MonitorStatus.ACTIVE, "is_muted": is_monitor_muted(monitor)},
         )
 
         # recompute per-project monitor check-in rate limit quota

src/sentry/monitors/serializers.py

@@ -1,6 +1,8 @@
 from collections import defaultdict
 from collections.abc import MutableMapping, Sequence
 from datetime import datetime
+from itertools import groupby
+from operator import attrgetter
 from typing import Any, Literal, TypedDict, cast
 
 from django.db.models import prefetch_related_objects
@@ -198,6 +200,30 @@ def get_attrs(self, item_list, user, **kwargs):
             for actor, serialized_actor in zip(filtered_actors, actors_serialized)
         }
 
+        # Query ALL environments (unfiltered) to determine muted status
+        # A monitor is muted only if ALL its environments are muted
+        all_monitor_environments = (
+            MonitorEnvironment.objects.filter(monitor__in=item_list)
+            .exclude(
+                status__in=[MonitorStatus.PENDING_DELETION, MonitorStatus.DELETION_IN_PROGRESS]
+            )
+            .order_by("monitor_id")
+        )
+
+        # Group environments by monitor
+        monitor_envs_by_id = {
+            monitor_id: list(envs)
+            for monitor_id, envs in groupby(all_monitor_environments, key=attrgetter("monitor_id"))
+        }
+
+        # A monitor is muted only if it has environments AND all of them are muted
+        is_muted_data = {
+            item.id: bool(monitor_envs_by_id.get(item.id, []))
+            and not any(not env.is_muted for env in monitor_envs_by_id.get(item.id, []))
+            for item in item_list
+        }
+
+        # Now query the filtered environments for serialization
         monitor_environments_qs = (
             MonitorEnvironment.objects.filter(monitor__in=item_list)
             .annotate(status_ordering=MONITOR_ENVIRONMENT_ORDERING)
@@ -213,6 +239,7 @@ def get_attrs(self, item_list, user, **kwargs):
 
         monitor_environments = list(monitor_environments_qs)
         serialized_monitor_environments = defaultdict(list)
+
         for monitor_env, serialized in zip(
             monitor_environments, serialize(monitor_environments, user)
         ):
@@ -227,6 +254,7 @@ def get_attrs(self, item_list, user, **kwargs):
                 "project": projects_data[item.project_id] if item.project_id else None,
                 "environments": environment_data[item.id],
                 "owner": actor_data.get(item.owner_actor),
+                "is_muted": is_muted_data[item.id],
             }
             for item in item_list
         }
@@ -245,7 +273,7 @@ def serialize(self, obj, attrs, user, **kwargs) -> MonitorSerializerResponse:
         result: MonitorSerializerResponse = {
             "id": str(obj.guid),
             "status": obj.get_status_display(),
-            "isMuted": obj.is_muted,
+            "isMuted": attrs["is_muted"],
             "isUpserting": obj.is_upserting,
             "name": obj.name,
             "slug": obj.slug,

tests/sentry/monitors/endpoints/test_base_monitor_details.py

@@ -18,6 +18,7 @@
     MonitorEnvironment,
     MonitorIncident,
     ScheduleType,
+    is_monitor_muted,
 )
 from sentry.monitors.types import DATA_SOURCE_CRON_MONITOR
 from sentry.monitors.utils import ensure_cron_detector, get_timeout_at
@@ -354,7 +355,7 @@ def test_can_mute(self) -> None:
         assert resp.data["slug"] == monitor.slug
 
         monitor = Monitor.objects.get(id=monitor.id)
-        assert monitor.is_muted
+        assert is_monitor_muted(monitor)
 
     def test_can_unmute(self) -> None:
         monitor = self._create_monitor()
@@ -367,7 +368,7 @@ def test_can_unmute(self) -> None:
         assert resp.data["slug"] == monitor.slug
 
         monitor = Monitor.objects.get(id=monitor.id)
-        assert not monitor.is_muted
+        assert not is_monitor_muted(monitor)
 
     def test_timezone(self) -> None:
         monitor = self._create_monitor()

tests/sentry/monitors/endpoints/test_base_monitor_environment_details.py

@@ -1,6 +1,6 @@
 from sentry.constants import ObjectStatus
 from sentry.deletions.models.scheduleddeletion import RegionScheduledDeletion
-from sentry.monitors.models import Monitor, MonitorEnvironment, MonitorStatus
+from sentry.monitors.models import Monitor, MonitorEnvironment, MonitorStatus, is_monitor_muted
 from sentry.testutils.cases import MonitorTestCase
 from sentry.testutils.helpers.datetime import freeze_time
 
@@ -72,7 +72,7 @@ def test_muting_all_environments_mutes_monitor(self) -> None:
 
         # Initially monitor should be unmuted
         monitor.refresh_from_db()
-        assert monitor.is_muted is False
+        assert is_monitor_muted(monitor) is False
 
         # Mute first environment
         self.get_success_response(
@@ -85,7 +85,7 @@ def test_muting_all_environments_mutes_monitor(self) -> None:
 
         # Monitor should still be unmuted (one environment is unmuted)
         monitor.refresh_from_db()
-        assert monitor.is_muted is False
+        assert is_monitor_muted(monitor) is False
 
         # Mute second environment
         self.get_success_response(
@@ -98,7 +98,7 @@ def test_muting_all_environments_mutes_monitor(self) -> None:
 
         # Now monitor should be muted (all environments are muted)
         monitor.refresh_from_db()
-        assert monitor.is_muted is True
+        assert is_monitor_muted(monitor) is True
 
     def test_unmuting_one_environment_unmutes_monitor(self) -> None:
         """Test that unmuting one environment when all were muted also unmutes the monitor."""
@@ -111,7 +111,7 @@ def test_unmuting_one_environment_unmutes_monitor(self) -> None:
 
         # Verify initial state
         monitor.refresh_from_db()
-        assert monitor.is_muted is True
+        assert is_monitor_muted(monitor) is True
 
         # Unmute one environment via the endpoint
         self.get_success_response(
@@ -124,7 +124,7 @@ def test_unmuting_one_environment_unmutes_monitor(self) -> None:
 
         # Monitor should now be unmuted
         monitor = Monitor.objects.get(id=monitor.id)
-        assert monitor.is_muted is False
+        assert is_monitor_muted(monitor) is False
         env1.refresh_from_db()
         assert env1.is_muted is False
         env2.refresh_from_db()

tests/sentry/monitors/endpoints/test_organization_detector_index.py

@@ -3,7 +3,7 @@
 from sentry.api.serializers import serialize
 from sentry.constants import ObjectStatus
 from sentry.monitors.grouptype import MonitorIncidentType
-from sentry.monitors.models import Monitor, ScheduleType
+from sentry.monitors.models import Monitor, ScheduleType, is_monitor_muted
 from sentry.monitors.serializers import MonitorSerializer
 from sentry.monitors.types import DATA_SOURCE_CRON_MONITOR
 from sentry.testutils.cases import APITestCase
@@ -205,7 +205,7 @@ def test_create_monitor_with_optional_fields(self):
         )
         assert monitor.name == "Full Config Monitor"
         assert monitor.status == ObjectStatus.DISABLED
-        assert monitor.is_muted is False
+        assert is_monitor_muted(monitor) is False
         assert monitor.config["schedule"] == "*/30 * * * *"
         assert monitor.config["checkin_margin"] == 15
         assert monitor.config["max_runtime"] == 120

tests/sentry/monitors/endpoints/test_organization_monitor_index.py

@@ -12,7 +12,7 @@
 from sentry.analytics.events.cron_monitor_created import CronMonitorCreated, FirstCronMonitorCreated
 from sentry.constants import DataCategory, ObjectStatus
 from sentry.models.rule import Rule, RuleSource
-from sentry.monitors.models import Monitor, MonitorStatus, ScheduleType
+from sentry.monitors.models import Monitor, MonitorStatus, ScheduleType, is_monitor_muted
 from sentry.monitors.utils import get_detector_for_monitor
 from sentry.quotas.base import SeatAssignmentResult
 from sentry.testutils.asserts import assert_org_audit_log_exists
@@ -150,7 +150,7 @@ def test_sort_muted(self) -> None:
             self._create_monitor(name="A monitor"),
             self._create_monitor(name="ZA monitor"),
         ]
-        monitors.sort(key=lambda m: (m.is_muted, m.name))
+        monitors.sort(key=lambda m: (is_monitor_muted(m), m.name))
 
         response = self.get_success_response(self.organization.slug, sort="muted")
         self.check_valid_response(response, monitors)
@@ -389,6 +389,45 @@ def test_ignore_pending_deletion_environments(self) -> None:
         assert len(response.data[0]["environments"]) == 1
         assert response.data[0]["environments"][0]["status"] == "ok"
 
+    def test_is_muted_calculated_from_all_envs_not_filtered(self) -> None:
+        """Test that isMuted field is calculated from ALL environments, not just filtered ones"""
+        # Monitor with prod unmuted, dev muted
+        monitor = self._create_monitor(name="Test Monitor")
+        self._create_monitor_environment(monitor, name="prod", is_muted=False)
+        self._create_monitor_environment(monitor, name="dev", is_muted=True)
+
+        # When viewing all environments, monitor should NOT be muted
+        # (because not ALL environments are muted)
+        response = self.get_success_response(self.organization.slug)
+        assert response.data[0]["isMuted"] is False
+
+        # When filtering to only "prod" environment, monitor should STILL not be muted
+        # even though we're only displaying prod in the environments array
+        response = self.get_success_response(self.organization.slug, environment=["prod"])
+        assert response.data[0]["isMuted"] is False
+        assert len(response.data[0]["environments"]) == 1
+        assert response.data[0]["environments"][0]["name"] == "prod"
+
+        # When filtering to only "dev" environment (which is muted),
+        # monitor should STILL not be muted because prod is unmuted
+        response = self.get_success_response(self.organization.slug, environment=["dev"])
+        assert response.data[0]["isMuted"] is False
+        assert len(response.data[0]["environments"]) == 1
+        assert response.data[0]["environments"][0]["name"] == "dev"
+
+        # Now mute ALL environments
+        monitor.monitorenvironment_set.update(is_muted=True)
+
+        # Monitor should now be muted regardless of environment filter
+        response = self.get_success_response(self.organization.slug)
+        assert response.data[0]["isMuted"] is True
+
+        response = self.get_success_response(self.organization.slug, environment=["prod"])
+        assert response.data[0]["isMuted"] is True
+
+        response = self.get_success_response(self.organization.slug, environment=["dev"])
+        assert response.data[0]["isMuted"] is True
+
 
 class CreateOrganizationMonitorTest(MonitorTestCase):
     endpoint = "sentry-api-0-organization-monitor-index"
@@ -655,8 +694,8 @@ def test_bulk_mute_unmute(self) -> None:
         monitor_two.refresh_from_db()
         env_one.refresh_from_db()
         env_two.refresh_from_db()
-        assert monitor_one.is_muted
-        assert monitor_two.is_muted
+        assert is_monitor_muted(monitor_one)
+        assert is_monitor_muted(monitor_two)
         assert env_one.is_muted
         assert env_two.is_muted
         assert_org_audit_log_exists(
@@ -681,8 +720,8 @@ def test_bulk_mute_unmute(self) -> None:
         monitor_two.refresh_from_db()
         env_one.refresh_from_db()
         env_two.refresh_from_db()
-        assert not monitor_one.is_muted
-        assert not monitor_two.is_muted
+        assert not is_monitor_muted(monitor_one)
+        assert not is_monitor_muted(monitor_two)
         assert not env_one.is_muted
         assert not env_two.is_muted
 
@@ -763,5 +802,5 @@ def test_disallow_when_no_open_membership(self) -> None:
 
         monitor.refresh_from_db()
         env.refresh_from_db()
-        assert not monitor.is_muted
+        assert not is_monitor_muted(monitor)
         assert not env.is_muted

tests/sentry/monitors/logic/test_mark_failed.py

@@ -16,6 +16,7 @@
     MonitorIncident,
     MonitorStatus,
     ScheduleType,
+    is_monitor_muted,
 )
 from sentry.testutils.cases import TestCase
 
@@ -100,7 +101,7 @@ def test_mark_failed_muted(self, mock_dispatch_incident_occurrence: mock.MagicMo
 
         monitor.refresh_from_db()
         monitor_environment.refresh_from_db()
-        assert monitor.is_muted
+        assert is_monitor_muted(monitor)
         assert monitor_environment.status == MonitorStatus.ERROR
 
         assert mock_dispatch_incident_occurrence.call_count == 0
@@ -342,7 +343,7 @@ def test_mark_failed_issue_threshold_disabled(
 
         monitor.refresh_from_db()
         monitor_environment.refresh_from_db()
-        assert monitor.is_muted
+        assert is_monitor_muted(monitor)
         assert monitor_environment.status == MonitorStatus.ERROR
 
         assert mock_dispatch_incident_occurrence.call_count == 0

tests/sentry/monitors/test_models.py

@@ -13,6 +13,7 @@
     MonitorEnvironmentLimitsExceeded,
     MonitorLimitsExceeded,
     ScheduleType,
+    is_monitor_muted,
 )
 from sentry.monitors.types import DATA_SOURCE_CRON_MONITOR
 from sentry.monitors.validators import ConfigValidator
@@ -454,7 +455,7 @@ def test_is_muted_all_environments_muted(self):
         )
 
         # Verify monitor.is_muted is True
-        assert monitor.is_muted is True
+        assert is_monitor_muted(monitor) is True
 
     def test_is_muted_some_environments_unmuted(self):
         """Test that monitor.is_muted returns False when any environment is unmuted."""
@@ -475,7 +476,7 @@ def test_is_muted_some_environments_unmuted(self):
         )
 
         # Verify monitor.is_muted is False
-        assert monitor.is_muted is False
+        assert is_monitor_muted(monitor) is False
 
     def test_is_muted_all_environments_unmuted(self):
         """Test that monitor.is_muted returns False when all environments are unmuted."""
@@ -496,12 +497,12 @@ def test_is_muted_all_environments_unmuted(self):
         )
 
         # Verify monitor.is_muted is False
-        assert monitor.is_muted is False
+        assert is_monitor_muted(monitor) is False
 
     def test_is_muted_no_environments(self):
         """Test that monitor.is_muted returns False when there are no environments."""
         monitor = self.create_monitor()
-        assert monitor.is_muted is False
+        assert is_monitor_muted(monitor) is False
 
     def test_is_muted_single_environment(self):
         """Test is_muted works correctly with a single environment."""
@@ -514,7 +515,7 @@ def test_is_muted_single_environment(self):
             is_muted=True,
         )
 
-        assert monitor.is_muted is True
+        assert is_monitor_muted(monitor) is True
 
         # Test with unmuted environment
         monitor2 = self.create_monitor()
@@ -525,4 +526,4 @@ def test_is_muted_single_environment(self):
             is_muted=False,
         )
 
-        assert monitor2.is_muted is False
+        assert is_monitor_muted(monitor2) is False