DB: create an index for builds_build table to improve Addons API (#…

…10840)

* DB: create an index for `builds_build` table to improve Addons API

After doing some research on #10831, I think that adding an index to this table
will help a lot to improve queries performance on Addons API.

This PR also fixes the `version.builds.last()` query to get the `Build` object
that is finished and successfull. Otherwise, we will be returning a build that
does not match with the HTML on S3.

I think we should close #10831 and revert the commit on `rel*` branches.

* Update readthedocs/proxito/views/hosting.py

* Update readthedocs/proxito/views/hosting.py

readthedocs/builds/migrations/0054_add_builds_index_for_addons.py

@@ -0,0 +1,20 @@
+# Generated by Django 4.2.6 on 2023-10-18 11:43
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("builds", "0053_alter_version_build_data"),
+    ]
+
+    operations = [
+        migrations.AlterIndexTogether(
+            name="build",
+            index_together={
+                ("date", "id"),
+                ("version", "state", "type"),
+                ("version", "state", "date", "success"),
+            },
+        ),
+    ]

readthedocs/builds/models.py

@@ -847,8 +847,11 @@ class Meta:
         ordering = ['-date']
         get_latest_by = 'date'
         index_together = [
-            ['version', 'state', 'type'],
-            ['date', 'id'],
+            # Useful for `/_/addons/` API endpoint.
+            # Query: ``version.builds.filter(success=True, state=BUILD_STATE_FINISHED)``
+            ["version", "state", "date", "success"],
+            ["version", "state", "type"],
+            ["date", "id"],
         ]
         indexes = [
             models.Index(fields=['project', 'date']),

readthedocs/proxito/views/hosting.py

@@ -17,7 +17,7 @@
     ProjectSerializer,
     VersionSerializer,
 )
-from readthedocs.builds.constants import EXTERNAL, LATEST
+from readthedocs.builds.constants import BUILD_STATE_FINISHED, EXTERNAL, LATEST
 from readthedocs.builds.models import Version
 from readthedocs.core.resolver import resolver
 from readthedocs.core.unresolver import UnresolverError, unresolver
@@ -77,7 +77,13 @@ def _resolve_resources(self):
             project = unresolved_url.project
             version = unresolved_url.version
             filename = unresolved_url.filename
-            build = version.builds.last()
+            # This query should use a particular index:
+            # ``builds_build_version_id_state_date_success_12dfb214_idx``.
+            # Otherwise, if the index is not used, the query gets too slow.
+            build = version.builds.filter(
+                success=True,
+                state=BUILD_STATE_FINISHED,
+            ).last()
 
         except UnresolverError as exc:
             # If an exception is raised and there is a ``project`` in the