fix(crons): Add index to `MonitorIncident` on `(monitor_enviroment, resolving_checkin)` (#63552)

Follow up to #inc-596. This index was already added temporarily to
resolve the incident, just making sure it's included permanently.

migrations_lockfile.txt

@@ -9,5 +9,5 @@ feedback: 0003_feedback_add_env
 hybridcloud: 0009_make_user_id_optional_for_slug_reservation_replica
 nodestore: 0002_nodestore_no_dictfield
 replays: 0003_add_size_to_recording_segment
-sentry: 0635_groupenvironment_index
+sentry: 0636_monitor_incident_env_resolving_index
 social_auth: 0002_default_auto_field

src/sentry/migrations/0636_monitor_incident_env_resolving_index.py

@@ -0,0 +1,33 @@
+# Generated by Django 3.2.23 on 2024-01-22 22:36
+
+from django.db import migrations, models
+
+from sentry.new_migrations.migrations import CheckedMigration
+
+
+class Migration(CheckedMigration):
+    # This flag is used to mark that a migration shouldn't be automatically run in production. For
+    # the most part, this should only be used for operations where it's safe to run the migration
+    # after your code has deployed. So this should not be used for most operations that alter the
+    # schema of a table.
+    # Here are some things that make sense to mark as dangerous:
+    # - Large data migrations. Typically we want these to be run manually by ops so that they can
+    #   be monitored and not block the deploy for a long period of time while they run.
+    # - Adding indexes to large tables. Since this can take a long time, we'd generally prefer to
+    #   have ops run this and not block the deploy. Note that while adding an index is a schema
+    #   change, it's completely safe to run the operation after the code has deployed.
+    is_dangerous = True
+
+    dependencies = [
+        ("sentry", "0635_groupenvironment_index"),
+    ]
+
+    operations = [
+        migrations.AddIndex(
+            model_name="monitorincident",
+            index=models.Index(
+                fields=["monitor_environment", "resolving_checkin"],
+                name="sentry_moni_monitor_a24312_idx",
+            ),
+        ),
+    ]

src/sentry/monitors/models.py

@@ -699,3 +699,4 @@ class MonitorIncident(Model):
     class Meta:
         app_label = "sentry"
         db_table = "sentry_monitorincident"
+        indexes = [models.Index(fields=["monitor_environment", "resolving_checkin"])]