Indeed, I had an attempt at doing this here (
https://github.com/django/django/pull/8928/), but it seems a hard problem.
I think there is huge potential here but I have no time to work on this
anymore.
On Tue, 17 Jul 2018, 19:00 Ramiro Morales, wrote:
> On Sat, Jun 30, 2018 at 12:40 PM Tom Forbe
On Sat, Jun 30, 2018 at 12:40 PM Tom Forbes wrote:
> Are you sure it is the prefetches that is causing this? As Adam pointed
> out these are correctly ignored. Annotations however are not, which can
> cause unnecessary work and longer execution times. i.e:
>
> Book.objects.annotate(something=Max(
I checked MySQL 8 today, and it's the same story. Does anyone know how this
performs in MariaDB or Postgresql?
On Friday, June 29, 2018 at 11:00:33 PM UTC+2, Jakub Kleň wrote:
>
> Hi guys, I came across a problem today while testing my webapp with a full
> migrations applied from my legacy site
Hi, thank you for your response.
I'm currently running MySQL 5.7.17, and the time difference between the
queries is really big (0.006s vs 16.6s).
I'm also wondering that something like this isn't handled by MySQL.
On Saturday, June 30, 2018 at 1:50:48 PM UTC+2, Adam Johnson wrote:
>
> it takes r
After some more investigation yesterday, I found out that it isn't the
prefetches and the subquery, and exactly as you write, it's annotations
which generate joins, and for count() the difference is it has to go thru
the whole db table, and that is slowing it down a lot. For my queryset, the
no
Are you sure it is the prefetches that is causing this? As Adam pointed out
these are correctly ignored. Annotations however are not, which can cause
unnecessary work and longer execution times. i.e:
Book.objects.annotate(something=Max('pages__word_count')).count()
We have enough information to b
>
> it takes really long to process by MySQL.
>
Which version? Subquery performance gets better in MySQL 5.6 and even more
so on MariaDB.
for count the query would be really simple, and wouldn't need the
> prefetches.
>
When counting, prefetches aren't actaully executed. Check the actual SQL
wi
Hi guys, I came across a problem today while testing my webapp with a full
migrations applied from my legacy site for the first time.
The problem is I'm using Prefetch in my view query (get_queryset), and it
works fine when I just fetch it, but the problem comes with the .count()
query which gen
