feat(migrations): Add new index to Incident model (#58207)

This PR adds a new index to `Incident` to make querying for the metric
alert rate limiting feature more efficient (#58032).

migrations_lockfile.txt

@@ -9,5 +9,5 @@ feedback: 0003_feedback_add_env
 hybridcloud: 0004_add_cache_version
 nodestore: 0002_nodestore_no_dictfield
 replays: 0003_add_size_to_recording_segment
-sentry: 0574_backfill_weekly_report_settings
+sentry: 0575_incident_date_added_index
 social_auth: 0002_default_auto_field

src/sentry/incidents/models.py

@@ -203,7 +203,10 @@ class Incident(Model):
         app_label = "sentry"
         db_table = "sentry_incident"
         unique_together = (("organization", "identifier"),)
-        index_together = (("alert_rule", "type", "status"),)
+        index_together = (
+            ("alert_rule", "type", "status"),
+            ("id", "date_added"),
+        )
 
     @property
     def current_end_date(self):

src/sentry/migrations/0575_incident_date_added_index.py

@@ -0,0 +1,30 @@
+# Generated by Django 3.2.20 on 2023-10-16 22:57
+
+from django.db import migrations
+
+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", "0574_backfill_weekly_report_settings"),
+    ]
+
+    operations = [
+        migrations.AlterIndexTogether(
+            name="incident",
+            index_together={("id", "date_added"), ("alert_rule", "type", "status")},
+        ),
+    ]