Make a few database performance optimisations

entries/migrations/0004_auto_20171027_0846.py

@@ -0,0 +1,27 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.11.6 on 2017-10-26 21:46
+from __future__ import unicode_literals
+
+from django.conf import settings
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('entries', '0003_remove_entry_summary'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='entry',
+            name='author',
+            field=models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='entries', to=settings.AUTH_USER_MODEL),
+        ),
+        migrations.AlterField(
+            model_name='entry',
+            name='kind',
+            field=models.CharField(choices=[('note', 'note'), ('article', 'article')], db_index=True, default='note', max_length=30),
+        ),
+    ]

entries/models.py

@@ -10,17 +10,29 @@ from . import kinds
 ENTRY_KINDS = [(k.id, k.id) for k in kinds.all]
 
 
+class EntryManager(models.Manager):
+    def get_queryset(self):
+        qs = super(EntryManager, self).get_queryset()
+        return qs.select_related('author').prefetch_related('syndications')
+
+
 class Entry(ModelMeta, models.Model):
+    objects = EntryManager()
     kind = models.CharField(
         max_length=30,
         choices=ENTRY_KINDS,
+        db_index=True,
         default=ENTRY_KINDS[0][0]
     )
 
     name = models.CharField(max_length=100, blank=True)
     content = models.TextField()
 
-    author = models.ForeignKey(get_user_model(), on_delete=models.CASCADE)
+    author = models.ForeignKey(
+        get_user_model(),
+        related_name='entries',
+        on_delete=models.CASCADE,
+    )
 
     published = models.DateTimeField()
     updated = models.DateTimeField()
@@ -70,7 +82,14 @@ class Entry(ModelMeta, models.Model):
         ordering = ['-published']
 
 
+class SyndicationManager(models.Manager):
+    def get_queryset(self):
+        qs = super(SyndicationManager, self).get_queryset()
+        return qs.select_related('profile__site')
+
+
 class Syndication(models.Model):
+    objects = SyndicationManager()
     entry = models.ForeignKey(
         Entry,
         related_name='syndications',

home/views.py

@@ -1,14 +1,14 @@
 from django.shortcuts import get_object_or_404, render
 from users.models import User
-from entries.models import Entry
 from lemoncurry import breadcrumbs
 
 breadcrumbs.add('home:index', 'home')
 
 
 def index(request):
-    user = get_object_or_404(User, pk=1)
-    entries = Entry.objects.filter(author=user)
+    query = User.objects.prefetch_related('entries', 'profiles', 'keys')
+    user = get_object_or_404(query, pk=1)
+    entries = user.entries.all()
     return render(request, 'home/index.html', {
         'user': user,
         'entries': entries,

users/models.py

@@ -1,5 +1,6 @@
 from django.db import models
 from django.contrib.auth.models import AbstractUser
+from django.utils.functional import cached_property
 from meta.models import ModelMeta
 
 
@@ -30,17 +31,17 @@ class User(ModelMeta, AbstractUser):
     def avatar_url(self):
         return self.avatar.url
 
-    @property
+    @cached_property
     def facebook_id(self):
         try:
-            return self.profiles.filter(site__name='Facebook')[0].username
+            return self.profiles.filter(site__name='Facebook').values('username')[0]['username']
         except IndexError:
             return None
 
-    @property
+    @cached_property
     def twitter_username(self):
         try:
-            return '@' + self.profiles.filter(site__name='Twitter')[0].username
+            return '@' + self.profiles.filter(site__name='Twitter').values('username')[0]['username']
         except IndexError:
             return None
 
@@ -53,7 +54,13 @@ class User(ModelMeta, AbstractUser):
     }
 
 
+class ProfileManager(models.Manager):
+    def get_queryset(self):
+        return super(ProfileManager, self).get_queryset().select_related('site')
+
+
 class Profile(models.Model):
+    objects = ProfileManager()
     user = models.ForeignKey(
         User,
         related_name='profiles',