add index for models

problem/migrations/0007_problem_problem_visible_idx.py

@@ -0,0 +1,20 @@
+# Generated by Django 6.0 on 2026-04-23 20:07
+
+from django.conf import settings
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('contest', '0003_acmcontestrank_acm_rank_contest_user_idx_and_more'),
+        ('problem', '0006_problem_problem_contest_visible_idx'),
+        migrations.swappable_dependency(settings.AUTH_USER_MODEL),
+    ]
+
+    operations = [
+        migrations.AddIndex(
+            model_name='problem',
+            index=models.Index(fields=['visible'], name='problem_visible_idx'),
+        ),
+    ]

problem/models.py

@@ -95,6 +95,7 @@ class Problem(models.Model):
         ordering = ("create_time",)
         indexes = [
             models.Index(fields=["contest", "visible"], name="problem_contest_visible_idx"),
+            models.Index(fields=["visible"], name="problem_visible_idx"),
         ]
 
     def add_submission_number(self):