Django 调试工具栏说我有一个重复 1367 次的查询

Question

我有一个简短的视图，但有一个复杂的查询（使用的模型来自数据库 MySQL 视图）。问题是当这个视图执行时，模板加载太慢了。 Django调试工具显示一个查询重复了1367次，但是重复查询与复杂的数据库视图查询无关。

1. 有什么办法可以避免重复查询吗？
2. 这是因为第二个查询造成的延迟吗？

下面是我的模板和视图代码。很抱歉没有把它们展示得太好，但这是我在 StackOverflow 上的第一篇文章。

def simbouloi_list(request, eklid):
    paramorder = request.GET.get('orderoption', '')

    try:
        paramorder = int(paramorder)
    except:
        paramorder = 6  # default ταξινόμηση

    selected_ekloges = Eklogestbl.objects.filter(eklid=eklid)
    # επιλογή όλων των εκλ. αναμετρήσεων με visible=1 και κάνω φθίνουσα ταξινόμηση  αν δεν δοθεί παράμετρος
    all_ekloges = Eklogestbl.objects.filter(visible=1).order_by('-eklid')

    #all_simbouloi = EklallsimbVw.objects.filter(eklid=eklid).order_by('surname', 'firstname', 'fathername')

    if paramorder==1 or paramorder==6:
        all_simbouloi = EklallsimbVw.objects.filter(eklid=eklid).order_by('surname', 'firstname','fathername')
    elif paramorder == 2:
        all_simbouloi = EklallsimbVw.objects.filter(eklid=eklid).order_by('sindiasmos', 'surname', 'firstname','fathername')
    elif paramorder == 3:
        all_simbouloi = EklallsimbVw.objects.filter(eklid=eklid).order_by('sindiasmos', 'toposeklogis', 'surname', 'firstname','fathername')
    elif paramorder == 4:
        all_simbouloi = EklallsimbVw.objects.filter(eklid=eklid).order_by( 'toposeklogis','sindiasmos','surname', 'firstname','fathername')
    else:
        all_simbouloi = EklallsimbVw.objects.filter(eklid=eklid).order_by('toposeklogis', 'surname','firstname', 'fathername')


    context = {'all_ekloges': all_ekloges,
               'selected_ekloges': selected_ekloges,
               'all_simbouloi': all_simbouloi,
               }

    return render(request, 'Elections/simbouloi_list.html' , context)

模板：

{% extends 'Elections/base.html' %}

{% load staticfiles %}

<!-- καλούμε το base.html που προσθέτει το σταθερό Menu -->

 {% block content %}


     {% include 'Elections/messages.html' %}


     <div class="page-header">

            <h3 align="center">Υποψήφιοι Σύμβουλοι (Δημοτικοί & Τοπικοί)</h3>
     </div>

 <div class="row">

       <div class="col-md-10 col-md-offset-1">

                  <form method="get" name="simbouloi">

                     <select   name="orderoption"  onchange="simbouloi.submit()">
                     <option  value="6" {% if selected_order ==  4  %}selected{%endif%}>--------Επιλογή ταξινόμησης--------</option>
                         <option  value="1" {% if selected_order ==  1  %}selected{%endif%}>Κατά Επώνυμο</option>
                         <option  value="2" {% if selected_order ==  2  %}selected{%endif%}>Κατά Συνδυασμό/Επώνυμο</option>
                         <option  value="3" {% if selected_order ==  3  %}selected{%endif%}>Κατά Συνδυασμό/Περ. Εκλογής/Επώνυμο</option>
                         <option  value="4" {% if selected_order ==  3  %}selected{%endif%}>Κατά Περ. Εκλογής/Συνδυασμό/Επώνυμο</option>
                         <option  value="5" {% if selected_order ==  3  %}selected{%endif%}>Κατά Περ. Εκλογής/Επώνυμο</option>

                     </select>
                     <input type="text" class="heighttext" id="livesearch" placeholder="live search"></input>
                  </form>

        <div class="divmargin"> </div>

                    <table>

                        <tbody >

                        <tr class="noborder"> <td colspan="4"><a href="{% url 'simbouloi_add' selected_ekloges.0.eklid%}" class="top-menu"><span class="glyphicon glyphicon-plus"></span> Νέα καταχώριση</a></td></tr>

                        </tbody>
                   </table>

                    <div class="divmargin"> </div>

                   <table class="table styletd1 table-condensed table-striped  table-hover">

                        <tbody >
                        <tr>
                                <td class="thick">Επώνυμο</td>
                                <td class="thick">Όνομα</td>
                                <td class="thick">Όν. Πατρός</td>
                                <td class="thick">Περιοχή Εκλογής</td>
                                <td class="thick">Συνδυασμός</td>
                                <td class="thick">Ενέργειες</td>
                        </tr>
                        {% for p in all_simbouloi %}
                              <tr>
                                <td > {{ p.surname }} </td>
                                <td > {{ p.firstname }}</td>
                                <td > {{ p.fathername }} </td>
                                <td > {{ p.toposeklogis }} </td>
                                <td > {% if  p.sindiasmos is None %} {% else %} {{ p.sindiasmos  }} {% endif %}</td>
                                <td>
                                    <a class="btn btn-default" href="{% url 'simbouloi_edit' selected_ekloges.0.eklid p.simbid%}"><span class="glyphicon glyphicon-pencil"></span></a>
                                    <a class="btn btn-default" href="{% url 'simbouloi_delete' selected_ekloges.0.eklid p.simbid%}"><span class="glyphicon glyphicon-minus"></span></a>
                                </td>

                              </tr>
                          {% endfor %}

                        </tbody>
                   </table>

                    <br/>

                    <table>

                        <tbody >

                        <tr class="noborder"> <td colspan="4"><a href="{% url 'simbouloi_add' selected_ekloges.0.eklid%}" class="top-menu"><span class="glyphicon glyphicon-plus"></span> Νέα καταχώριση</a></td></tr>

                        </tbody>
                   </table>



        </div>
</div>




{% endblock %}

Answer 1

我认为我不能使用以下命令：

selected_ekloges = all_ekloges.objects.prefetch_related('eklallsimbvw_set').get(eklid=eklid) all_simbouloi = selected_ekloges.eklallsimbvw_set.all()

因为“eklallsimbvw”是由“inspect_db”命令自动创建的模型，它描述的是Mysql VIEW而不是TABLE，所以这个模型没有与“Eklogestbl”模型相关的外键（正如我对“prefetch”命令的理解)。

对于第一个命令，它还会引发类似“'QuerySet' object has no attribute 'objects'”的错误。

这是我的 EklallsimbVw 模型：

class EklallsimbVw(models.Model):
id = models.IntegerField(primary_key=True)
eklid = models.IntegerField(db_column='eklID',db_index=True)  # Field name made lowercase.
simbid = models.IntegerField(db_column='simbID',db_index=True)  # Field name made lowercase.
surname = models.CharField(db_column='surname', max_length=100,db_index=True)
firstname = models.CharField(db_column='firstname', max_length=100,db_index=True)
fathername = models.CharField(db_column='fathername', max_length=100,db_index=True)
comments = models.CharField(db_column='comments', max_length=100)
toposeklogisid = models.IntegerField(db_column='toposEklogisID')  # Field name made lowercase.
toposeklogis = models.CharField(db_column='toposEklogis', max_length=100)  # Field name made lowercase.
eidoskoinotitas = models.IntegerField(db_column='eidosKoinotitas', blank=True, null=True)  # Field name made lowercase.
sindid = models.IntegerField(db_column='sindID', blank=True, null=True,db_index=True)  # Field name made lowercase.
sindiasmos = models.CharField(db_column='sindiasmos', max_length=100, blank=True, null=True,db_index=True)

这是“Eklogestbl”模型：

class Eklogestbl(models.Model):
eklid = models.AutoField(db_column='eklID', primary_key=True, db_index=True)  # Field name made lowercase.
descr = models.CharField(unique=True, max_length=100)
dateofelection = models.DateField(db_column='dateOfElection', blank=True, null=True)  # Field name made lowercase.
dimos = models.CharField(max_length=100, blank=True)
sisid = models.ForeignKey('Sistima', models.DO_NOTHING, db_column='sisID', db_index=True)  # Field name made lowercase.
edrid = models.ForeignKey(Edres, models.DO_NOTHING, db_column='edrID', db_index=True)  # Field name made lowercase.
visible=models.IntegerField(db_column='visible', default=1)
defaultelection=models.IntegerField(db_column='defaultElection', default=1)

Answer 2

试试这个，django 查询集评估的良好起点https://docs.djangoproject.com/en/2.1/ref/models/querysets/

def simbouloi_list(request, eklid):
 paramorder = 6  # default ταξινόμηση
 all_ekloges = Eklogestbl.objects.filter(visible=1).order_by('-eklid')
 if 'orderoption' in request.GET:
    paramorder = int(request.GET.get('orderoption'))

 selected_ekloges = all_ekloges.objects.prefetch_related('eklalallsimbwv_set').get(eklid=eklid) 
 all_simbouloi = selected_ekloges.eklalallsimbwv_set.all()

 if paramorder==1 or paramorder==6:
    all_simbouloi = all_simbouloi.order_by('surname', 'firstname','fathername') # dosen't hit the database
 elif paramorder == 2:
    all_simbouloi = all_simbouloi.order_by('sindiasmos', 'surname', 'firstname','fathername') # dosen't hit the database
 elif paramorder == 3:
    all_simbouloi = all_simbouloi.order_by('sindiasmos', 'toposeklogis', 'surname', 'firstname','fathername') # dosen't hit the database
elif paramorder == 4:
    all_simbouloi = all_simbouloi.order_by( 'toposeklogis','sindiasmos','surname', 'firstname','fathername') # dosen't hit the database
else:
    all_simbouloi = all_simbouloi.order_by('toposeklogis', 'surname','firstname', 'fathername') # dosen't hit the database


context = {'all_ekloges': all_ekloges,
           'selected_ekloges': selected_ekloges,
           'all_simbouloi': all_simbouloi,
           }

return render(request, 'Elections/simbouloi_list.html' , context)

更新

下面的代码终于完美运行了！

selected_ekloges = Eklogestbl.objects.prefetch_related('eklallsimbvw_set').get(eklid=eklid)

all_simbouloi = selected_ekloges.eklallsimbvw_set.all().values_list('simbid', 'surname', 'firstname', 'fathername', 'toposeklogis', 'sindiasmos')

if paramorder==1 or paramorder==6:
    all_simbouloi = all_simbouloi.order_by('surname', 'firstname','fathername')
elif paramorder == 2:
    all_simbouloi = all_simbouloi.order_by('sindiasmos', 'surname', 'firstname','fathername')
elif paramorder == 3:
    all_simbouloi = all_simbouloi.order_by('sindiasmos', 'toposeklogis', 'surname', 'firstname','fathername')
elif paramorder == 4:
    all_simbouloi = all_simbouloi.order_by( 'toposeklogis','sindiasmos','surname', 'firstname','fathername')
else:
    all_simbouloi = all_simbouloi.order_by('toposeklogis', 'surname','firstname', 'fathername')

context = {'all_ekloges': all_ekloges,
           'selected_ekloges': selected_ekloges.eklid,
           'all_simbouloi': all_simbouloi,
           }

非常感谢！