Query with multiple annotations slows down
0
I've got a query which returns users with additional info
Here are my simplified models:
class Event(..):
creator = models.ForeignKey('users.User', on_delete=models.CASCADE, related_name='event_creator_set')
class Participator(..):
status = models.CharField(..)
event = models.ForeignKey('events.Event', on_delete=models.CASCADE, related_name='participators_set')
user = models.ForeignKey('users.User', on_delete=models.CASCADE, related_name='participations_set')
My method from User Manager:
def additional_info(self):
from events.models import Participator
participated_events_count = Count(
'participations_set',
distinct=True,
filter=(~Q(participations_set__event__creator=F('id')) & Q(
participations_set__status=Participator.PARTICIPATED))
)
return self.get_queryset()
.annotate(created_events_count=Count('events_set',
distinct=True))
.annotate(followers_count=Count(
'followers_set',
filter=(Q(followers_set__is_following=True)),
distinct=True))
.annotate(
participated_events_count=participated_events_count)
Everything works great without the last annotate, but when I'm trying to add participated_events_count value - query performed up to 30 seconds
UPDATED
If I remove random annotate with Count - query performs very fast
django django-orm
asked Nov 13 '18 at 11:28
ErnstErnst
96112
add a comment |
0
I've got a query which returns users with additional info
Here are my simplified models:
class Event(..):
creator = models.ForeignKey('users.User', on_delete=models.CASCADE, related_name='event_creator_set')
class Participator(..):
status = models.CharField(..)
event = models.ForeignKey('events.Event', on_delete=models.CASCADE, related_name='participators_set')
user = models.ForeignKey('users.User', on_delete=models.CASCADE, related_name='participations_set')
My method from User Manager:
def additional_info(self):
from events.models import Participator
participated_events_count = Count(
'participations_set',
distinct=True,
filter=(~Q(participations_set__event__creator=F('id')) & Q(
participations_set__status=Participator.PARTICIPATED))
)
return self.get_queryset()
.annotate(created_events_count=Count('events_set',
distinct=True))
.annotate(followers_count=Count(
'followers_set',
filter=(Q(followers_set__is_following=True)),
distinct=True))
.annotate(
participated_events_count=participated_events_count)
Everything works great without the last annotate, but when I'm trying to add participated_events_count value - query performed up to 30 seconds
UPDATED
If I remove random annotate with Count - query performs very fast
django django-orm
asked Nov 13 '18 at 11:28
ErnstErnst
96112
add a comment |
0
0
0
I've got a query which returns users with additional info
Here are my simplified models:
class Event(..):
creator = models.ForeignKey('users.User', on_delete=models.CASCADE, related_name='event_creator_set')
class Participator(..):
status = models.CharField(..)
event = models.ForeignKey('events.Event', on_delete=models.CASCADE, related_name='participators_set')
user = models.ForeignKey('users.User', on_delete=models.CASCADE, related_name='participations_set')
My method from User Manager:
def additional_info(self):
from events.models import Participator
participated_events_count = Count(
'participations_set',
distinct=True,
filter=(~Q(participations_set__event__creator=F('id')) & Q(
participations_set__status=Participator.PARTICIPATED))
)
return self.get_queryset()
.annotate(created_events_count=Count('events_set',
distinct=True))
.annotate(followers_count=Count(
'followers_set',
filter=(Q(followers_set__is_following=True)),
distinct=True))
.annotate(
participated_events_count=participated_events_count)
Everything works great without the last annotate, but when I'm trying to add participated_events_count value - query performed up to 30 seconds
UPDATED
If I remove random annotate with Count - query performs very fast
django django-orm
asked Nov 13 '18 at 11:28
ErnstErnst
96112
I've got a query which returns users with additional info
Here are my simplified models:
class Event(..):
creator = models.ForeignKey('users.User', on_delete=models.CASCADE, related_name='event_creator_set')
class Participator(..):
status = models.CharField(..)
event = models.ForeignKey('events.Event', on_delete=models.CASCADE, related_name='participators_set')
user = models.ForeignKey('users.User', on_delete=models.CASCADE, related_name='participations_set')
My method from User Manager:
def additional_info(self):
from events.models import Participator
participated_events_count = Count(
'participations_set',
distinct=True,
filter=(~Q(participations_set__event__creator=F('id')) & Q(
participations_set__status=Participator.PARTICIPATED))
)
return self.get_queryset()
.annotate(created_events_count=Count('events_set',
distinct=True))
.annotate(followers_count=Count(
'followers_set',
filter=(Q(followers_set__is_following=True)),
distinct=True))
.annotate(
participated_events_count=participated_events_count)
Everything works great without the last annotate, but when I'm trying to add participated_events_count value - query performed up to 30 seconds
UPDATED
If I remove random annotate with Count - query performs very fast
django django-orm
django django-orm
asked Nov 13 '18 at 11:28
ErnstErnst
96112
asked Nov 13 '18 at 11:28
ErnstErnst
96112
edited Nov 13 '18 at 13:03
Ernst
asked Nov 13 '18 at 11:28
ErnstErnst
96112
asked Nov 13 '18 at 11:28
ErnstErnst
96112
asked Nov 13 '18 at 11:28
ErnstErnst
96112
96112
add a comment |
add a comment |
1 Answer
1
active
oldest
votes
0
You can use .prefetch_related() to lookup the related objects and reduce the number of additional queries.
return self.get_queryset().prefetch_related('participations_set')/
...
You can use Django Debug Toolbar to get a breakdown of queries on each page.
answered Nov 13 '18 at 12:22
bdoubleubdoubleu
617112
I added all needed params toprefetch_related(), but it doesn't help. Also I'm building only API, so debug toolbar isn't useful for me
– Ernst
Nov 13 '18 at 12:52
If you create a simple view with DDT enabled that passes the queryset as context then you will be able to see a breakdown of the repeated queries and exactly what is causing your slowdown. It's hard to tell from your example but I'm guessing the slowdown is because your filter is causing (at least) 3 queries for each object inparticipations_set
– bdoubleu
Nov 13 '18 at 17:52
add a comment |
Your Answer
StackExchange.ifUsing("editor", function () {
StackExchange.using("externalEditor", function () {
StackExchange.using("snippets", function () {
StackExchange.snippets.init();
});
});
}, "code-snippets");
StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "1"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);
StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});
function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: true,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: 10,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});
}
});
draft saved
draft discarded
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53280047%2fquery-with-multiple-annotations-slows-down%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
0
You can use .prefetch_related() to lookup the related objects and reduce the number of additional queries.
return self.get_queryset().prefetch_related('participations_set')/
...
You can use Django Debug Toolbar to get a breakdown of queries on each page.
answered Nov 13 '18 at 12:22
bdoubleubdoubleu
617112
I added all needed params toprefetch_related(), but it doesn't help. Also I'm building only API, so debug toolbar isn't useful for me
– Ernst
Nov 13 '18 at 12:52
If you create a simple view with DDT enabled that passes the queryset as context then you will be able to see a breakdown of the repeated queries and exactly what is causing your slowdown. It's hard to tell from your example but I'm guessing the slowdown is because your filter is causing (at least) 3 queries for each object inparticipations_set
– bdoubleu
Nov 13 '18 at 17:52
add a comment |
0
You can use .prefetch_related() to lookup the related objects and reduce the number of additional queries.
return self.get_queryset().prefetch_related('participations_set')/
...
You can use Django Debug Toolbar to get a breakdown of queries on each page.
answered Nov 13 '18 at 12:22
bdoubleubdoubleu
617112
I added all needed params toprefetch_related(), but it doesn't help. Also I'm building only API, so debug toolbar isn't useful for me
– Ernst
Nov 13 '18 at 12:52
If you create a simple view with DDT enabled that passes the queryset as context then you will be able to see a breakdown of the repeated queries and exactly what is causing your slowdown. It's hard to tell from your example but I'm guessing the slowdown is because your filter is causing (at least) 3 queries for each object inparticipations_set
– bdoubleu
Nov 13 '18 at 17:52
add a comment |
0
0
0
You can use .prefetch_related() to lookup the related objects and reduce the number of additional queries.
return self.get_queryset().prefetch_related('participations_set')/
...
You can use Django Debug Toolbar to get a breakdown of queries on each page.
answered Nov 13 '18 at 12:22
bdoubleubdoubleu
617112
You can use .prefetch_related() to lookup the related objects and reduce the number of additional queries.
return self.get_queryset().prefetch_related('participations_set')/
...
You can use Django Debug Toolbar to get a breakdown of queries on each page.
answered Nov 13 '18 at 12:22
bdoubleubdoubleu
617112
answered Nov 13 '18 at 12:22
bdoubleubdoubleu
617112
answered Nov 13 '18 at 12:22
bdoubleubdoubleu
617112
answered Nov 13 '18 at 12:22
bdoubleubdoubleu
617112
617112
I added all needed params toprefetch_related(), but it doesn't help. Also I'm building only API, so debug toolbar isn't useful for me
– Ernst
Nov 13 '18 at 12:52
If you create a simple view with DDT enabled that passes the queryset as context then you will be able to see a breakdown of the repeated queries and exactly what is causing your slowdown. It's hard to tell from your example but I'm guessing the slowdown is because your filter is causing (at least) 3 queries for each object inparticipations_set
– bdoubleu
Nov 13 '18 at 17:52
add a comment |
I added all needed params toprefetch_related(), but it doesn't help. Also I'm building only API, so debug toolbar isn't useful for me
– Ernst
Nov 13 '18 at 12:52
If you create a simple view with DDT enabled that passes the queryset as context then you will be able to see a breakdown of the repeated queries and exactly what is causing your slowdown. It's hard to tell from your example but I'm guessing the slowdown is because your filter is causing (at least) 3 queries for each object inparticipations_set
– bdoubleu
Nov 13 '18 at 17:52
I added all needed params to
prefetch_related(), but it doesn't help. Also I'm building only API, so debug toolbar isn't useful for me– Ernst
Nov 13 '18 at 12:52
I added all needed params to
prefetch_related(), but it doesn't help. Also I'm building only API, so debug toolbar isn't useful for me– Ernst
Nov 13 '18 at 12:52
If you create a simple view with DDT enabled that passes the queryset as context then you will be able to see a breakdown of the repeated queries and exactly what is causing your slowdown. It's hard to tell from your example but I'm guessing the slowdown is because your filter is causing (at least) 3 queries for each object in
participations_set– bdoubleu
Nov 13 '18 at 17:52
If you create a simple view with DDT enabled that passes the queryset as context then you will be able to see a breakdown of the repeated queries and exactly what is causing your slowdown. It's hard to tell from your example but I'm guessing the slowdown is because your filter is causing (at least) 3 queries for each object in
participations_set– bdoubleu
Nov 13 '18 at 17:52
add a comment |
draft saved
draft discarded
Thanks for contributing an answer to Stack Overflow!
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
To learn more, see our tips on writing great answers.
draft saved
draft discarded
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53280047%2fquery-with-multiple-annotations-slows-down%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
