fix(groupowners): Add index on type and json commit id. (#89892)

We have an extremely slow query here:
https://github.com/getsentry/sentry/blob/1f6701a4e13a45eb1aedae31e5a2cb41d80892f8/src/sentry/integrations/github/tasks/pr_comment.py#L79-L98

Both `type` and the json `commit` id column are not indexed. Adding an
index here to manage this query.

This produces an index like 
```
CREATE INDEX CONCURRENTLY "groupowner_type_json_commitid" ON "sentry_groupowner" ("type", (((("context")::jsonb ->> 'commitId'))::bigint));
```
Which *should* fix the problem, but we'll see in prod

Author: wedamija

migrations_lockfile.txt

@@ -21,7 +21,7 @@ remote_subscriptions: 0003_drop_remote_subscription
 
 replays: 0004_index_together
 
-sentry: 0865_file_offsets
+sentry: 0866_grouptype_index
 
 social_auth: 0002_default_auto_field
 

src/sentry/migrations/0866_grouptype_index.py

@@ -0,0 +1,46 @@
+# Generated by Django 5.1.7 on 2025-04-17 18:42
+
+import django.db.models.fields.json
+import django.db.models.functions.comparison
+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.
+    # 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 post deployment:
+    # - Large data migrations. Typically we want these to be run manually 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
+    #   run this outside deployments so that we don't block them. Note that while adding an index
+    #   is a schema change, it's completely safe to run the operation after the code has deployed.
+    # Once deployed, run these manually via: https://develop.sentry.dev/database-migrations/#migration-deployment
+
+    is_post_deployment = True
+
+    dependencies = [
+        ("sentry", "0865_file_offsets"),
+    ]
+
+    operations = [
+        migrations.AddIndex(
+            model_name="groupowner",
+            index=models.Index(
+                models.F("type"),
+                django.db.models.functions.comparison.Cast(
+                    django.db.models.fields.json.KeyTextTransform(
+                        "commitId",
+                        django.db.models.functions.comparison.Cast(
+                            models.F("context"), models.JSONField()
+                        ),
+                    ),
+                    models.BigIntegerField(),
+                ),
+                name="groupowner_type_json_commitid",
+            ),
+        ),
+    ]

src/sentry/models/groupowner.py

@@ -9,6 +9,10 @@
 
 from django.conf import settings
 from django.db import models
+from django.db.models import BigIntegerField, F
+from django.db.models import JSONField as DjangoJSONField
+from django.db.models.fields.json import KeyTextTransform
+from django.db.models.functions import Cast
 from django.utils import timezone
 
 from sentry.backup.scopes import RelocationScope
@@ -77,6 +81,20 @@ class Meta:
         app_label = "sentry"
         db_table = "sentry_groupowner"
 
+        indexes = [
+            models.Index(
+                F("type"),
+                Cast(
+                    KeyTextTransform(
+                        "commitId",
+                        Cast(F("context"), DjangoJSONField()),
+                    ),
+                    BigIntegerField(),
+                ),
+                name="groupowner_type_json_commitid",
+            ),
+        ]
+
     def save(self, *args, **kwargs):
         keys = [k for k in (self.user_id, self.team_id) if k is not None]
         assert len(keys) != 2, "Must have team or user or neither, not both"