Telemetry: create index to speed up queries (#12432)

Fixes https://read-the-docs.sentry.io/issues/5537486737/

Author: humitos

readthedocs/telemetry/migrations/0002_created_index.py

@@ -0,0 +1,19 @@
+# Generated by Django 5.2.4 on 2025-08-22 12:14
+
+from django.db import migrations
+from django.db import models
+from django_safemigrate import Safe
+
+
+class Migration(migrations.Migration):
+    safe = Safe.before_deploy()
+    dependencies = [
+        ("telemetry", "0001_initial"),
+    ]
+
+    operations = [
+        migrations.AddIndex(
+            model_name="builddata",
+            index=models.Index(fields=["created"], name="telemetry_b_created_31070a_idx"),
+        ),
+    ]

readthedocs/telemetry/models.py

@@ -110,6 +110,10 @@ def collect(self, build, data):
 class BuildData(TimeStampedModel):
     class Meta:
         verbose_name_plural = "Build data"
+        indexes = [
+            # Speeds up `delete_old_build_data` task.
+            models.Index(fields=["created"]),
+        ]
 
     data = models.JSONField()
     objects = BuildDataManager()