django - 改进我的数据库查询的可能方法？

Question

我目前正在使用附加的脚本从我的 django 数据库中获取一个独立且（希望）唯一的数据集，但是与最终文件大小（20MB 的格式化 XML）相比，完成所需的时间变得荒谬，我认为我有办法大幅改进它，但我没有这样做的经验。

在这组查询中，您是否可以发现任何地方让我的速度非常慢？

我很想参考 django 查询优化技术和教程！

此处游戏的目的是返回由一家公司提供的所有配件，包括在应用程序的另一个实例中重新创建该数据所需的所有数据。基本上我是在出口配件。本节只是关于将数据转换为我自己的序列化程序的正确格式。

TL：博士；帮助加快此代码的速度，同时保持相同的输出！需要10 4分钟！

@print_timing
def get_fittings(company_id):
    print "i'm getting Fittings"

    models = []
    result = []
    company_list = []
    company_list.append(Company.objects.filter(pk=company_id))
    print "Got Company"

    address_list = []
    address_list.append(Address.objects.filter(company=company_id))
    print "Got Address"

    customer_list = []
    customer_list.append(Customer.objects.filter(company=company_id))
    print "Got Customers"

    supplier_list = []
    supplier_list_internal = Supplier.objects.filter(company=company_id)
    supplier_list.append(supplier_list_internal)
    print "Got Supplier"

    fitting_supplier_list = []
    fitting_supplier_list_internal = FittingSupplier.objects.filter(supplier__in=supplier_list_internal)
    fitting_supplier_list.append(fitting_supplier_list_internal)
    print "Got Fitting Supplier"

    supplies_list = []
    supplies_list.append(Supplies.objects.filter(supplier__in=supplier_list_internal))
    print "Got Supplies"

    costbook_number = setup.Costbook.objects.filter(type="fittings").aggregate(max_number=model.Max('number'))
    this_costbook_list = FittingItemSupplierCost.objects.filter(supplier__in=fitting_supplier_list_internal, costbook_number=costbook_number['max_number'])

    fitting_list = []
    for this_costbook in this_costbook_list:
        fitting_list.append(Fitting.objects.filter(uuid=this_costbook.fitting_item.fitting.uuid))
    print "Got Fitting List"

    manufacturer_list = []

    for fitting_queryset in fitting_list:
        for fitting in fitting_queryset:
            if fitting.manufacturer != None:

                company_list.append(Company.objects.filter(uuid=fitting.manufacturer.company.uuid))

                address_list.append(Address.objects.filter(company=fitting.manufacturer.company.uuid))

                customer_list.append(Customer.objects.filter(company=fitting.manufacturer.company.uuid))

                manufacturer_list.append(Manufacturer.objects.filter(uuid=fitting.manufacturer.uuid))

    contacts_list = []
    for addresses in address_list:
        contacts_list.append(Contact.objects.filter(address__in=addresses))

    print "Got Companys and Addresses and Contacts and Customers and Manufacturers"

    fitting_supplier_list = []
    for fitting_supplier in fitting_supplier_list:
        fitting_list.append(Fitting.objects.filter(uuid=fitting_supplier.fitting.uuid))
    print "Got Fittings"

    #empty the list of FittingSuppliers
    fitting_item_list = []
    image_list = []
    for fitting_queryset in fitting_list:
        for fitting in fitting_queryset:
            fitting_item_list.append(fitting.item_set.all())
            image_list.append(FileStore.objects.filter(filename=fitting.image))
    print "Got FittingItem and FileStore"

    for fitting_queryset in fitting_list:
        fitting_supplier_list.append(FittingSupplier.objects.filter(fitting__in=fitting_queryset))
    print "Got FittingSupplier"

    fitting_item_supplier_cost_list = []
    for fitting_supplier_queryset in fitting_supplier_list:
        fitting_item_supplier_cost_list.append(FittingItemSupplierCost.objects.filter(supplier__in=fitting_supplier_queryset, costbook_number=costbook_number['max_number']))
    print "Got FittingItemSupplierCost"

    for company in company_list:
        result.append(company)
        models.append("Company")

    for address in address_list:
        result.append(address)
        models.append("Address")

    for contacts in contacts_list:
        result.append(contacts)
        models.append("Contact")

    for customer in customer_list:
        result.append(customer)
        models.append("Customer")

    for supplier in supplier_list:
        result.append(supplier)
        models.append("Supplier")   

    for supplies in supplies_list:
        result.append(supplies)
        models.append("Supplies")

    for manufacturer in manufacturer_list:
        result.append(manufacturer)
        models.append("Manufacturer")

    for fitting in fitting_list:
        result.append(fitting)   
        models.append("Fitting")

    for fitting_item in fitting_item_list:
        result.append(fitting_item)
        models.append("FittingItem")

    for image in image_list:
        result.append(image)
        models.append("Filestore")

    for fitting_supplier in fitting_supplier_list:
        result.append(fitting_supplier)
        models.append("FittingSupplier")

    for fitting_item_supplier_cost in fitting_item_supplier_cost_list:
        result.append(fitting_item_supplier_cost)
        models.append("FittingItemSupplierCost")

    #result, models = get_fitting_packs(company_id, result, models)

    return result, models

型号（有很多！）：

class Company(models.Model):
    uuid = UUIDField(primary_key=True)
    name =  models.CharField(null=True, blank=True,max_length=255,verbose_name=_('Company Name'))
    internal_name = models.CharField(null=True, blank=True,max_length=255,verbose_name=_('Internal Name'))
    reference = models.CharField(null=True, blank=True,max_length=255,verbose_name=_('Reference'))
    company_status = models.ForeignKey(CompanyStatus, null=True, db_column='company_status_uuid',verbose_name=(_('Company Status')))
    vat_number = models.CharField(null=True, blank=True,max_length=255,verbose_name=(_('Vat Number')))
    registration_number = models.CharField(null=True, blank=True,max_length=255,verbose_name=(_('Company Number')))
    discount = models.FloatField(null=True, blank=True)
    notes = models.TextField(null=True, blank=True,max_length=255)
    jms_code = models.TextField(null=True, blank=True,max_length=255)
    logo = models.TextField(null=True, blank=True,max_length=255)
    date_created = models.DateTimeField(null=True, blank=True, auto_now_add=True,verbose_name=_('Date Time'), serialize=False)
    date_modified = models.DateTimeField(null=True, blank=True, auto_now=True,verbose_name=_('Date Time Updated'), serialize=False)
    hidden = models.NullBooleanField(null=True, blank=True,default=0, serialize=False)
    user = UserField(null=True, blank=True, serialize=False)
    is_modified = ModifiedField(serialize=False)
    companyid = models.IntegerField(null=True, blank=True, serialize=False)
    seqno = models.IntegerField(null=True, blank=True, serialize=False)

class Address(models.Model):
    uuid = UUIDField(primary_key=True)
    company = models.ForeignKey(Company, db_column='company_uuid',null=True,blank=True,verbose_name=_('Address'))
    group_name = models.CharField(null=True, blank=False,max_length=255,verbose_name=_('Corporate Group'))
    line1 = models.CharField(null=True, blank=False,max_length=255,verbose_name=_('Address Line 1'))
    line2 = models.CharField(null=True, blank=True,max_length=255,verbose_name=_('Address Line 2'))
    line3 = models.CharField(null=True, blank=True,max_length=255,verbose_name=_('Address Line 3'))
    town = models.CharField(null=True, blank=True,max_length=255)
    county = models.CharField(null=True, blank=True,max_length=255)
    postcode = models.CharField(null=True, blank=True,max_length=255)
    country_iso = models.CharField(null=True, blank=True,max_length=255)
    telephone = models.CharField(null=True, blank=True,max_length=255)
    fax = models.CharField(null=True, blank=True,max_length=255)
    email = models.CharField(null=True, blank=True,max_length=255)
    website = models.CharField(null=True, blank=True,max_length=255)
    description = models.CharField(null=True, blank=True,max_length=255)
    date_created = models.DateTimeField(null=True, blank=True, auto_now_add=True, serialize=False)
    date_modified = models.DateTimeField(null=True, blank=True, auto_now=True, serialize=False)
    user = UserField(null=True, blank=True, serialize=False)
    jms_code = models.CharField(null=True, blank=True,max_length=255)
    notes = models.CharField(null=True, blank=True,max_length=255, serialize=False)    
    is_modified = ModifiedField(serialize=False)

class Contact(models.Model):
    uuid = UUIDField(primary_key=True)
    address = models.ForeignKey(Address, db_column='address_uuid',null=True,blank=True,verbose_name=_('Address'))
    title = models.ForeignKey(Title,db_column='title_uuid',null=True, blank=True)
    forename = models.CharField(null=True, blank=True,max_length=255)
    surname = models.CharField(null=True, blank=True,max_length=255)
    position = models.CharField(db_column='job_title',null=True, blank=True,max_length=255)
    mobile = models.CharField(null=True, blank=True,max_length=255)
    direct_line = models.CharField(null=True, blank=True,max_length=255)
    email = models.CharField(null=True, blank=True,max_length=255)
    origin = models.IntegerField(null=True, blank=True)
    lead_source = models.IntegerField(null=True, blank=True)
    notes = models.TextField(null=True, blank=True, serialize=False)
    contact_status = models.ForeignKey(ContactStatus, db_column='contact_status_uuid',verbose_name=_('Contact Status'), serialize=False)
    contact_method = models.ForeignKey(ContactMethod, db_column='contact_method_uuid',verbose_name=_('Contact Method'), serialize=False)
    date_created = models.DateTimeField(null=True, blank=True, auto_now_add=True, serialize=False)
    date_modified = models.DateTimeField(null=True, blank=True, auto_now=True, serialize=False)
    user = UserField(null=True, blank=True, serialize=False)
    jms_code = models.CharField(null=True, blank=True,max_length=255)
    is_modified = ModifiedField(serialize=False)

class Customer(models.Model):
    uuid = UUIDField(primary_key=True)
    company  = models.ForeignKey(Company, db_column='company_uuid',null=True, blank=True)
    customer_sector = models.ForeignKey(CustomerSector, db_column='customer_sector_uuid',null=True, blank=True,verbose_name=_('Sector'))
    account_number = models.CharField(null=True, blank=True,max_length=255,verbose_name="Account No")
    reference  = models.CharField(null=True, blank=True,max_length=255)
    notes = models.TextField(null=True, blank=True)
    customer_status = models.IntegerField(null=True, blank=True)
    date_created = models.DateTimeField(null=True, blank=True, auto_now_add=True)
    date_modified = models.DateTimeField(null=True, blank=True, auto_now=True)
    user = UserField(null=True, blank=True)
    jms_code = models.CharField(null=True, blank=True,max_length=255)

class Supplier(models.Model):
    uuid = UUIDField(primary_key=True)
    company  = models.ForeignKey(Company, db_column='company_uuid',null=True, blank=True)
    sector = models.ForeignKey(CustomerSector, db_column='sector_uuid',null=True, blank=True,verbose_name=_('Sector'))
    account_number = models.CharField(null=True, blank=True,max_length=255,verbose_name=_('Account No'))
    reference  = models.CharField(null=True, blank=True,max_length=255)
    notes = models.TextField(null=True, blank=True) 
    date_created = models.DateTimeField(null=True, blank=True, auto_now_add=True)
    date_modified = models.DateTimeField(null=True, blank=True, auto_now=True)
    user = UserField(null=True, blank=True)
    jms_code = models.CharField(null=True, blank=True,max_length=255)

class Supplies(models.Model):
    uuid = UUIDField(primary_key=True)
    supplier  = models.ForeignKey(Supplier, db_column='supplier_uuid',null=True, blank=True)
    bought_in_control_panel  = models.ForeignKey('boughtin.BoughtInControlPanel', db_column='bought_in_control_panel_id',null=True, blank=True)

class Costbook(models.Model):
    COSTBOOK_TYPES = [
        ('glass', 'Glass'),
        ('timber', 'Timber'),
        ('fittings', 'Fittings'),
        ('misc', 'Miscellaneous'),
    ]
    uuid                = UUIDField(primary_key=True)
    number              = models.IntegerField(null=True, blank=True, editable=False)
    type                = models.CharField(null=True, blank=True, max_length=50, editable=False, choices=COSTBOOK_TYPES)
    name                = models.CharField(null=True, blank=True, max_length=255)
    date_created        = models.DateTimeField(null=True, blank=True, editable=False)
    date_modified       = models.DateTimeField(null=True, blank=True, auto_now=True, editable=False)
    user                = UserField(null=True, blank=True)

class FittingItemSupplierCost(CostbookCostEntry):
    cost_type = (
        (BI_COST_MANUAL, _('Default Cost')),
        (BI_COST_REQUEST, _('Request Cost'))         
    )

#    IMPORTANT: the following fields INHERITED from CostbookCostEntry (setp.models) 

#    uuid = UUIDField(primary_key=True)
#    costbook = models.ForeignKey(Costbook, db_column='costbook_uuid',null=True, blank=True)
#    costbook_number = models.IntegerField(null=True, blank=True, editable=False)
#    net_cost  = models.FloatField(_('Net Cost'),null=True, blank=True,default='0')
#    charge_out = models.FloatField(_('Charge out'),null=True, blank=True)

    rrp = models.FloatField(_('RRP'),null=True, blank=True)
    fitting_item = models.ForeignKey(FittingItem, db_column='fitting_item_uuid',null=True, blank=True, editable=False, related_name='supplier_cost_set')
    supplier = models.ForeignKey(FittingSupplier, db_column='fitting_supplier_uuid',null=True, blank=True)
    code = models.CharField(null=True, blank=False,max_length=255)
    cost_type = models.IntegerField(null=True, blank=True, choices=cost_type)
    user = UserField(null=True, blank=True, serialize=False)
    date_time_updated  = models.DateTimeField(null=True, blank=True, auto_now=True)  

class Fitting(models.Model):
    uuid                         = UUIDField(primary_key=True)
    bought_in_control_panel_file = models.ForeignKey(BoughtInControlPanelFile, db_column='bought_in_control_panel_file_id',null=True, blank=True)
    name                         = models.CharField(_('name'),null=True, blank=False,max_length=255)                           # Accessed by the get_name property
    code                         = models.CharField(_('Code'),null=True, blank=True,max_length=255)
    default_colour               = models.ForeignKey(Colour, db_column='default_colour_uuid',null=True, blank=True)
    material                     = models.ForeignKey(Material, db_column='material_uuid',null=True, blank=True)
    material_finish              = models.ForeignKey(MaterialFinish, db_column='material_finish_uuid',null=True, blank=True)
    pricing_type                 = models.IntegerField(_('pricing type'), choices=PRICING_TYPE)
    sales_description            = models.CharField(_('Sales Description'),null=True, blank=False,max_length=255)              # Accessed by the get_sales_description property
    purchase_description         = models.CharField(_('Purchase Description'),null=True, blank=False,max_length=255)           # Accessed by the get_purchase_description property
    workshop_description         = models.CharField(_('Workshop Description'),null=True, blank=False,max_length=255)           # Accessed by the get_workshop_description property
    notes                        = models.TextField(null=True, blank=True) 
    manufacturer                 = models.ForeignKey(Manufacturer, db_column='manufacturer_uuid',null=True, blank=True)
    manufacturer_code            = models.CharField(_('Manufacturer code'),null=True, blank=False,max_length=100)
    specification                = models.TextField(null=True, blank=False)
    limit_weight_min             = models.FloatField(_('Min Weight'), null=True, blank=True)
    limit_weight_max             = models.FloatField(_('Max Weight'), null=True, blank=True)
    limit_height_min             = models.FloatField(_('Min Height'), null=True, blank=True)
    limit_height_max             = models.FloatField(_('Max Height'), null=True, blank=True)
    limit_width_min              = models.FloatField(_('Min Width'), null=True, blank=True)
    limit_width_max              = models.FloatField(_('Max Width'), null=True, blank=True)
    fire_rating                  = models.ForeignKey(FireRating, db_column='fire_rating_id',null=True, blank=True)
    u_value                      = models.FloatField(_('U-value'),default=0)
    acoustic_rating              = models.FloatField(_('Acoustic Rating'),default=0)
    image                        = models.ImageField(_('Image'),upload_to=_fitting_image_upload_path, storage=DatabaseImageStorage(), null=True, blank=True)
    fitting_quantity_type        = models.ForeignKey(FittingQuantityType,db_column='fitting_quantity_type_id', null=True, blank=True)
    allow_profile                = models.BooleanField(default=0)
    profile_xml                  = models.TextField(null=False, blank=True)
    jms_default_cost             = models.FloatField(_('JMS Default Cost'),null=True, blank=True)
    disabled                     = models.BooleanField(default=0)
    date_time_updated            = models.DateTimeField(null=True, blank=True, auto_now=True)

class Manufacturer(models.Model):
    uuid = UUIDField(primary_key=True)
    company  = models.ForeignKey(Company, db_column='company_uuid',null=True, blank=True)
    account_number = models.CharField(null=True, blank=True,max_length=255,verbose_name=_('Account No'))
    reference  = models.CharField(null=True, blank=True,max_length=255)
    notes = models.TextField(null=True, blank=True)
    date_created = models.DateTimeField(null=True, blank=True, auto_now_add=True)
    date_modified = models.DateTimeField(null=True, blank=True, auto_now=True)
    user = UserField(null=True, blank=True)
    jms_code = models.CharField(null=True, blank=True,max_length=255)

class FittingItem(models.Model, BoughtinItemMixin):
    uuid = UUIDField(primary_key=True)
    bought_in_control_panel_file = models.ForeignKey(BoughtInControlPanelFile, db_column='bought_in_control_panel_file_id',null=True, blank=True)
    fitting = models.ForeignKey(Fitting, db_column='fitting_uuid',null=True, related_name = 'item_set')
    unit_size = models.FloatField('Base Quantity', null=False, blank=False)
    unit_count = models.IntegerField('Multiplier', null=False, blank=False)

class FileStore(models.Model):
    uuid = UUIDField(primary_key=True)
    filename = models.CharField(max_length=255)
    data_base64 = models.TextField(null=True, blank=False)
    size = models.IntegerField(null=False, blank=False)

class FittingSupplier(models.Model):
    uuid = UUIDField(primary_key=True)
    fitting = models.ForeignKey(Fitting, db_column='fitting_uuid',null=True, blank=True, related_name='supplier_set')
    supplier = models.ForeignKey(Supplier, db_column='supplier_uuid',null=True, blank=True)
    rating = models.IntegerField(null=True, blank=True)
    markup = models.FloatField(_('markup'),null=True, blank=True)
    disabled = models.IntegerField(null=True, blank=True)
    date_time_updated  = models.DateTimeField(null=True, blank=True, auto_now=True)

Answer 1

一些东西：

• 你不应该迭代查询集，除非你必须这样做。
• 你应该只得到你需要的东西。
• 你有很多冗余代码。
• 使用 django-debug-toolbar，并且很开心。
• 几乎可以肯定，您想要的信息可以在一两个查询集中返回。没有看到你的模型，很难知道如何最好地回答这个问题。
• 与上述相关，您的问题是什么？在您提供模型之后

Answer 2

目前尚不清楚您要检索的内容，它看起来result包含或多或少与company_id. 你不只是需要配件吗？

无论如何，您经常会做一件事，那就是：

for x in a_previous_queryset:
    blop += list(Something.objects.filter(x=x.uuid))

在这里，您正在对 中的每个元素进行一次查询a_previous_queryset，而您可以这样做：

blop = Something.objects.filter(x__in=a_previous_queryset)

这将为所有内容创建一个查询集。您的代码可能还有很多其他事情要做。

另外，我不知道你为什么list每次查询。

更广泛地说，你真的应该尝试理解，首先，每个查询实际上做了什么（阅读文档和 connection.queries 有好处），其次，django 提供的所有选项是什么（查询集上的文档很好为了那个原因）。

Answer 3

当您使用 DEBUG=True 运行 Django 时，会保留查询执行时间以供以后分析。这是Django 文档的相关部分：

确保您的 Django DEBUG 设置设置为 True。然后，只需这样做：

from django.db import connection
connection.queries [{'sql': 'SELECT polls_polls.id,polls_polls.question,polls_polls.pub_date FROM
polls_polls', 'time': '0.002'}]