I have a model Table which gets a new entry every few seconds, so it's a quite big table. class Table(models.Model): id: int pk: int timestamp = models.PositiveBigIntegerField(db_index=True) Now what i am trying to do is get the first entry for the last 24h. And for some reason it takes way to much time. Like we are talking about seconds. But if i try to get last i get it instantly. I've tried following queries: from_ts = int(time.time()) - 24 * 60 * 60 first_entry = Table.objects.filter(timestamp__gte=from_ts).first() first_entry = Table.objects.filter(timestamp__gte=from_ts).aggregate(Min('id')) They both take a few seconds to complete but if I try .aggregate(Min('timestamp')) it returns almost instantly. I tried .filter(timestamp__gte=from_ts)[0] which is quick and does work but i know its undefined behaviour because the entries aren't sorted and in some edge cases it might not work. Then i tried to just get the whole query in python and find min in python and it was almost instant. first_entry = min(list(Table.objects.filter(timestamp__gte=from_ts))) Can anyone explain what exactly is happening here and what is the cleanest/best solution? Continue reading...
