Why response time with postgres is 15x higher than with sqlite? - django

Question

Simple get request (django + django-rest-framework) with sqlite3 database takes 2ms.
Using postgres, response time extends to over 30ms. Why is that, how to make postgres faster?
Settings with sqlite:
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.sqlite3',
'NAME': BASE_DIR / 'db.sqlite3',
}
}
Settings with postgres:
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.postgresql_psycopg2',
'NAME': 'drf-test',
'USER': 'postgres',
'PASSWORD': 'postgres',
'HOST': 'localhost',
'PORT': '5432',
}
}
class Product(models.Model):
name = models.CharField(max_length=50)
description = models.CharField(max_length=150, blank=True)
price = models.DecimalField(max_digits=5, decimal_places=2, default=0)
class Meta:
verbose_name = ("Product")
verbose_name_plural = ("Products")
def __str__(self):
return self.name
class ProductListAPIView(ListAPIView):
queryset = Product.objects.all()
serializer_class = ProductModelSerializer
class ProductModelSerializer(serializers.ModelSerializer):
class Meta:
model = Product
fields = '__all__'

Answer 1

That difference is practically negligible.
Postgres is running a server essentially, so there could be I/O difference in timing. SQLite is file based, and you probably have a really small SQLite file/not many rows in your tables. Because of this, sqlite parsing will be very fast. But don't use SQLite in production; in this case, once the file starts growing, it'll not only consume more memory but also take much longer to parse through and your server response time will be much longer.