[英]How to optimize Django SQL SELECT Query on views.py?
这些是视图中涉及的模型:
class Movie(models.Model):
title_original = models.CharField(max_length=300,
db_column='titulooriginal')
title_translated = models.CharField(max_length=300, blank=True,
db_column='titulotraducido')
thumbnail = models.CharField(max_length=300, blank=True,
db_column='imagen')
length = models.CharField(max_length=75, db_column='duracion')
rating = models.CharField(max_length=75, db_column='censura')
genre = models.CharField(max_length=75, db_column='genero')
country_of_origin = models.CharField(max_length=150, db_column='pais')
trailer = models.CharField(max_length=300, blank=True, db_column='trailer')
synopsis = models.CharField(max_length=3600, blank=True,
db_column='sinopsis')
cast = models.CharField(max_length=300, blank=True, db_column='elenco')
director = models.CharField(max_length=150, db_column='director')
slug = models.SlugField(unique=True, blank=True)
tsc = models.DateTimeField(auto_now=False, auto_now_add=True, db_column='tsc', null=True)
tsm = models.DateTimeField(auto_now=True, auto_now_add=True, db_column='tsm', null=True)
class Meta:
db_table = u'peliculas'
def __unicode__(self):
return self.title_original
class ShowTime(models.Model):
LANGUAGE_ESPANOL = 'Espanol'
LANGUAGE_SUBTITLED = 'Subtitulada'
LANGUAGE_CHOICES = (
(LANGUAGE_ESPANOL, LANGUAGE_ESPANOL),
(LANGUAGE_SUBTITLED, LANGUAGE_SUBTITLED))
movie = models.ForeignKey(Movie, db_column='idpelicula')
theater = models.ForeignKey(Theater, db_column='idcine',
null=True)
time = models.TimeField(null=True, db_column='hora')
type_3d = models.NullBooleanField(db_column=u'3d')
type_xd = models.NullBooleanField(null=True, db_column='xd')
type_gtmax = models.NullBooleanField(null=True, db_column='gtmax')
type_vip = models.NullBooleanField(null=True, db_column='vip')
type_imax = models.NullBooleanField(null=True, db_column='imax')
language = models.CharField(max_length=33, blank=True, db_column='idioma',
choices=LANGUAGE_CHOICES,
default=LANGUAGE_ESPANOL)
city = models.ForeignKey(City, db_column='idciudad')
start_date = models.DateField(blank=True, db_column='fecha_inicio')
end_date = models.DateField(blank=True, db_column='fecha_fin')
visible = models.NullBooleanField(null=True, db_column='visible')
tsc = models.DateTimeField(auto_now=False, auto_now_add=True, db_column='tsc', null=True)
tsm = models.DateTimeField(auto_now=True, auto_now_add=True, db_column='tsm', null=True)
class Meta:
db_table = u'funciones'
def __unicode__(self):
return (unicode(self.theater) + " " + unicode(self.movie.title_original) + " " + unicode(self.time))
另外,这是查询模型的视图:
def list_movies(request, time_period):
city = utils.get_city_from_request(request)
if time_period == 'proximas-dos-horas':
(start_date,
end_date,
hours_start,
hours_end) = utils.get_datetime_filters_from_time_period(time_period)
else:
(start_date,
end_date) = utils.get_datetime_filters_from_time_period(time_period)
if not start_date: # 404 for invalid time periods
raise Http404
movies = Movie.objects.filter(
showtime__city=city.code,
showtime__visible=1,
).order_by('-tsm').distinct()
if time_period == 'proximas-dos-horas':
movies = movies.filter(
showtime__start_date__lte=start_date,
showtime__end_date__gte=end_date,
showtime__time__range=(hours_start, hours_end))
elif time_period == 'proximos-estrenos':
movies = movies.filter(
showtime__start_date=None,
showtime__end_date=None,
)
else:
movies = movies.filter(
showtime__start_date__lte=start_date,
showtime__end_date__gte=end_date)
context = {'movies': movies, 'city': city, 'time_period': time_period}
return render_to_response('list_movies.html', context,
context_instance=RequestContext(request))
当前,此视图消耗了数据库中的大量资源,这导致浏览器上的Web事务响应时间很短。 我将应用程序与New Relic监视软件连接起来,以分析应用程序和数据库级别的事务。 这是我得到的跟踪详细信息:
我想获得关于优化此视图的somo建议,以便将数据库资源的消耗降至最低
非常感谢!
我不知道您遇到的问题,但是我的2条建议是:
首先,考虑数据模型中的一些更改。 ShowTime
类具有City
的外键和Theater
的外键,这似乎有点多余。 就个人而言,我更喜欢对地址进行非规范化,例如:
class Theater(models.Model):
name = models.CharField(max_length=48)
# Location fields.
geo_country = models.CharField(max_length=48)
geo_country_code = models.CharField(max_length=2)
geo_locality = models.CharField(max_length=48)
geo_street = models.CharField(max_length=48, blank=True, default="")
geo_address = models.CharField(max_length=120, blank=True, default="")
class ShowTime(models.Model):
theater = models.ForeignKey(Theater)
这样,您可以将JOIN保存到City
表中,并且可以从数据模型中将其删除。
其次,阅读Django ORM的select_related功能 。
祝你玩得开心。
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