Closes #18191: Remove duplicate SQL indexes (#19074)

* Closes #18191: Remove redundant SQL indexes

* Update developer documentation

* Add a system check for duplicate indexes

docs/development/extending-models.md

@@ -6,7 +6,7 @@ Below is a list of tasks to consider when adding a new field to a core model.
 
 Add the field to the model, taking care to address any of the following conditions.
 
-* When adding a GenericForeignKey field, also add an index under `Meta` for its two concrete fields. For example:
+* When adding a GenericForeignKey field, you may need add an index under `Meta` for its two concrete fields. (This is required only for non-unique GFK relationships, as the unique constraint introduces its own index.) For example:
 
     ```python
     class Meta:

netbox/core/apps.py

@@ -19,6 +19,7 @@ class CoreConfig(AppConfig):
 
     def ready(self):
         from core.api import schema  # noqa: F401
+        from core.checks import check_duplicate_indexes  # noqa: F401
         from netbox.models.features import register_models
         from . import data_backends, events, search  # noqa: F401
         from netbox import context_managers  # noqa: F401

netbox/core/checks.py

@@ -0,0 +1,41 @@
+from django.core.checks import Error, register, Tags
+from django.db.models import Index, UniqueConstraint
+from django.apps import apps
+
+__all__ = (
+    'check_duplicate_indexes',
+)
+
+
+@register(Tags.models)
+def check_duplicate_indexes(app_configs, **kwargs):
+    """
+    Check for an index which is redundant to a declared unique constraint.
+    """
+    errors = []
+
+    for model in apps.get_models():
+        if not (meta := getattr(model, "_meta", None)):
+            continue
+
+        index_fields = {
+            tuple(index.fields) for index in getattr(meta, 'indexes', [])
+            if isinstance(index, Index)
+        }
+        constraint_fields = {
+            tuple(constraint.fields) for constraint in getattr(meta, 'constraints', [])
+            if isinstance(constraint, UniqueConstraint)
+        }
+
+        # Find overlapping definitions
+        if duplicated := index_fields & constraint_fields:
+            for fields in duplicated:
+                errors.append(
+                    Error(
+                        f"Model '{model.__name__}' defines the same field set {fields} in both `Meta.indexes` and "
+                        f"`Meta.constraints`.",
+                        obj=model,
+                    )
+                )
+
+    return errors

netbox/core/migrations/0014_remove_redundant_indexes.py

@@ -0,0 +1,25 @@
+# Generated by Django 5.2b1 on 2025-04-03 18:32
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('core', '0013_datasource_sync_interval'),
+    ]
+
+    operations = [
+        migrations.RemoveIndex(
+            model_name='autosyncrecord',
+            name='core_autosy_object__c17bac_idx',
+        ),
+        migrations.RemoveIndex(
+            model_name='datafile',
+            name='core_datafile_source_path',
+        ),
+        migrations.RemoveIndex(
+            model_name='managedfile',
+            name='core_managedfile_root_path',
+        ),
+    ]

netbox/core/models/data.py

@@ -310,9 +310,6 @@ class DataFile(models.Model):
                 name='%(app_label)s_%(class)s_unique_source_path'
             ),
         )
-        indexes = [
-            models.Index(fields=('source', 'path'), name='core_datafile_source_path'),
-        ]
         verbose_name = _('data file')
         verbose_name_plural = _('data files')
 
@@ -387,8 +384,5 @@ class AutoSyncRecord(models.Model):
                 name='%(app_label)s_%(class)s_object'
             ),
         )
-        indexes = (
-            models.Index(fields=('object_type', 'object_id')),
-        )
         verbose_name = _('auto sync record')
         verbose_name_plural = _('auto sync records')

netbox/core/models/files.py

@@ -58,9 +58,6 @@ class ManagedFile(SyncedDataMixin, models.Model):
                 name='%(app_label)s_%(class)s_unique_root_path'
             ),
         )
-        indexes = [
-            models.Index(fields=('file_root', 'file_path'), name='core_managedfile_root_path'),
-        ]
         verbose_name = _('managed file')
         verbose_name_plural = _('managed files')
 

netbox/dcim/migrations/0207_remove_redundant_indexes.py

@@ -0,0 +1,17 @@
+# Generated by Django 5.2b1 on 2025-04-03 18:32
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('dcim', '0206_load_module_type_profiles'),
+    ]
+
+    operations = [
+        migrations.RemoveIndex(
+            model_name='cabletermination',
+            name='dcim_cablet_termina_884752_idx',
+        ),
+    ]

netbox/dcim/models/cables.py

@@ -299,9 +299,6 @@ class CableTermination(ChangeLoggedModel):
 
     class Meta:
         ordering = ('cable', 'cable_end', 'pk')
-        indexes = (
-            models.Index(fields=('termination_type', 'termination_id')),
-        )
         constraints = (
             models.UniqueConstraint(
                 fields=('termination_type', 'termination_id'),

netbox/vpn/migrations/0009_remove_redundant_indexes.py

@@ -0,0 +1,21 @@
+# Generated by Django 5.2b1 on 2025-04-03 18:32
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('vpn', '0008_add_l2vpn_status'),
+    ]
+
+    operations = [
+        migrations.RemoveIndex(
+            model_name='l2vpntermination',
+            name='vpn_l2vpnte_assigne_9c55f8_idx',
+        ),
+        migrations.RemoveIndex(
+            model_name='tunneltermination',
+            name='vpn_tunnelt_termina_c1f04b_idx',
+        ),
+    ]

netbox/vpn/models/l2vpn.py

@@ -110,9 +110,6 @@ class L2VPNTermination(NetBoxModel):
 
     class Meta:
         ordering = ('l2vpn',)
-        indexes = (
-            models.Index(fields=('assigned_object_type', 'assigned_object_id')),
-        )
         constraints = (
             models.UniqueConstraint(
                 fields=('assigned_object_type', 'assigned_object_id'),

netbox/vpn/models/tunnels.py

@@ -138,9 +138,6 @@ class TunnelTermination(CustomFieldsMixin, CustomLinksMixin, TagsMixin, ChangeLo
 
     class Meta:
         ordering = ('tunnel', 'role', 'pk')
-        indexes = (
-            models.Index(fields=('termination_type', 'termination_id')),
-        )
         constraints = (
             models.UniqueConstraint(
                 fields=('termination_type', 'termination_id'),