On Monday, March 16, 2015 at 5:19:38 PM UTC+8, Sardor Muminov wrote:
>
>
>
> Hello there,
>
>
> I am trying to perform aggregation from all objects which have one foreign
> key.
>
>
> These are my models:
>
> ...
>
> class Post(models.Model):
> id = models.CharField(max_length=255, primary_key=True)
>
>
> message = models.TextField()
> created_time = models.DateTimeField(db_index=True)
> updated_time = models.DateTimeField()
> creator = models.ForeignKey(Member, db_index=True)
> likes = models.IntegerField(db_index=True)
>
>
> class Comment(models.Model):
> id = models.CharField(max_length=255, primary_key=True, db_index=True)
> message = models.TextField()
> created_time = models.DateTimeField(db_index=True)
> creator = models.ForeignKey(Member, db_index=True)
> post = models.ForeignKey(Post, db_index=True)
> likes = models.IntegerField(db_index=True)
>
> ...
>
>
> And this is my query:
>
> top_commented_posts = Post.objects.annotate(
> num_comments=Count('comment')).order_by('-num_comments')[:10]
>
>
top_commented_posts =
Comment.objects.values('post').annotrate(post_count=Count('pk')).order_by('-post_count')
The rest is to construct above result with Posts to display in template.
Regards,
Chenxiong Qi
> In my template, I iterate over top_commented_posts:
>
> ...
>
> {% for post in top_commented_posts %}
> <tr>
> <td>{{ forloop.counter }}.</td>
> <td>{{ post.message | slice:"25"}}...</td>
> <td>{{ post.num_comments }}</td>
> <td><a class="btn btn-xs btn-inverse" href="
> https://www.mydomain.com/{{ post.id }}/" target="_blank"><span
> class="icon-link"></span></a></td>
> </tr>
> {% endfor %}
>
> ...
>
>
> This operations is one of the 27 ones from one page.
>
> Django debug toolbar result:
> 5335.56 ms (27 queries)
>
> 26 each queries taking between 1.44ms (min) and 227ms (max).
>
>
> Please, share your experience and advices on how can I optimize this query.
> I have also attached Django debug toolbar screenshot.
>
>
> Thanks in advance,
> Sardor
>
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