Despite the temptation of buying new servers and adding CPU and RAM – you need to do what you can with the code first. I am exploring and cataloguing these methods to speed up Django QuerySets before server scaling.
The general idea is simple – use more QuerySet methods instead of Python methods to avoid evaluation.
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If you need to modify instance fields depending on the instance’s pk or id, hop on.
When you create an instance, before it is saved, you can’t have pk or id as it is not yet created.
def save(self, *args, **kwargs):
# self.pk == None
# self.id == None
super().save(*args, **kwargs)
# self.pk != None
# self.id != None If you have a property that somehow depends on the value of self.pk or self.id and you want to have it saved on creating, you have two options.
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Just sort QuerySet with Django built-in methods, man.
So you are casually overriding get_queryset() in a, say, ListView, like this:
def get_queryset(self):
entries = [x for x in Entry.objects.all() if x.publications]
return entriesBecause you need to sort the Entry table by a reverse M2M relation publications and then BAM!:
Attribute error 'list' object has no attribute 'filter'Without a trace of the line you made a mistake in…
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Django Investigations 