Question

问题：

服务器对呼叫的响应（由opbeat，DHC chrome客户端测量）是大约500ms到5000ms。 Postgres查询（总计，每次通话）比相应的响应时间快约20x-50x。为什么这么慢？！？

背景信息：

我在webfaction上运行了一个实时tastypie API（共享实例，1 gig ram :(）用于我们的移动应用.Django 1.8，Python 2.7,0.12.2.dev0 tastypie，PostgreSQL 9.4。，CentOS7
db有大约40个表，~2gigs，6k用户（可能有1/3是＆＃39;活动＆＃39;），db位于dbs的单独共享webfaction框中。
虽然我们在api中确实有一些过程代码，但许多慢速调用只是对用户资源的GET - 最大/最慢是〜50kb记录，JSON响应中约350个对象。这次调用的postgres时间约为20-50ms，快速专用开发服务器上DHC的最快时间约为2秒 - 2gig ram，2 procs--现场约4秒，最慢约为10-16秒框。
在Apache / mod_wsgi上运行，HTTPS，（apache的基准很快），没有gzip。 httpd.conf设置似乎很好。

简而言之：

99％的时间花在了tastypie.resources.wrapper上 - 我还没有搞乱这段代码。这些调用只是调用返回资源。
数据库查询很快
网络服务器似乎很快。

诊断：

Django调试工具栏（用于在dev专用框上最慢的最慢操作调用）

用户CPU时间1926.979毫秒

系统CPU时间27.074毫秒

总CPU时间1954.053毫秒

经历的时间1980.884毫秒

上下文切换71自愿，44非自愿

的httpd.conf

LoadModule authz_core_module modules/mod_authz_core.so

LoadModule dir_module        modules/mod_dir.so

LoadModule env_module        modules/mod_env.so

LoadModule log_config_module modules/mod_log_config.so

LoadModule mime_module       modules/mod_mime.so

LoadModule rewrite_module    modules/mod_rewrite.so

LoadModule setenvif_module   modules/mod_setenvif.so

LoadModule wsgi_module       modules/mod_wsgi.so

LoadModule unixd_module      modules/mod_unixd.so

...

KeepAlive Off

SetEnvIf X-Forwarded-SSL on HTTPS=1

ServerLimit 1

StartServers 1

MaxRequestWorkers 5

MinSpareThreads 1

MaxSpareThreads 3

ThreadsPerChild 5

...

WSGIApplicationGroup %{GLOBAL}

WSGIDaemonProcess djangoapp processes=2 threads=8 python-path=...

WSGIProcessGroup djangoapp

WSGIRestrictEmbedded On

WSGILazyInitialization On

活动服务器上的Opbeat （这个抓取有更多/更长的数据库查询，我正在测试删除selecte_related（）/ prefetch_related（） - 它们帮助了数据库查询时间，但没有多少关闭总时间）：

Wtf，10张发布图片的声誉？

最后的想法：

tastypie这么慢吗？当然不是。虽然更好的盒子运行它〜更快，但是花了2秒才能完成db 20ms的操作是否现实？
是的，当我把它放在一个更快，专用的开发盒上时，时间会有所下降，但它们仍然是执行SQL调用所需时间的10-50倍，例如：对于资源GET来说，它们仍然是2秒，这对于db＆lt; 50毫秒。所以，它似乎不仅仅是资源问题，AFAIK。
我尝试链接到亚马逊RDS postgres db，但它的时间比db呼叫慢20倍（微/免费等级），而且总往返时间也慢一些。
感谢您的帮助和兴趣 -

Answer 1

在我的调查中，var leaseList = (from l in leases.tblfLeaseDetails join a in leases.tblfAuthorizations on l.Lease_Detail_ID equals a.Lease_Detail_ID into la from jla in (from aj in leases.tblfAuthorizations where aj.Lease_Detail_ID == l.Lease_Detail_ID orderby aj.Authorized_Date descending select aj).Take(1).DefaultIfEmpty() join p in leases.tblfPayments on l.Lease_Detail_ID equals p.Lease_Detail_ID into lp from jlp in (from pj in leases.tblfPayments where pj.Lease_Detail_ID == l.Lease_Detail_ID orderby pj.Payment_Date descending select pj).Take(1).DefaultIfEmpty() join v in leases.tblvVendors on l.Vendor_ID equals v.Vendor_ID into lv from jlv in lv.DefaultIfEmpty() join c in leases.tblvCounties on l.County_ID equals c.County_ID into lc from jlc in lc.DefaultIfEmpty() select new LeaseViewModel() { Lease_Detail_ID = l.Lease_Detail_ID, Vendor_Name = jlv.Vendor_Name, County = jlc.County, Authorization = jla.Authorized, Payment_Date = jlp.Payment_Date }).Distinct()速度很慢，因此功能Tastypie很慢。

我以这种方式从django.core.urlresolvers.reverse辞职并修补resource_uri：

django_app /猴/ tastypie.py

Tastypie

django_app /猴/的初始化的.py

from __future__ import absolute_import from django.core.exceptions import ObjectDoesNotExist from tastypie.bundle import Bundle from tastypie.exceptions import ApiFieldError def dehydrate(self, bundle, for_list=True): if not bundle.obj or not bundle.obj.pk: if not self.null: raise ApiFieldError( "The model '%r' does not have a primary key and can not be used in a ToMany context." % bundle.obj) return [] the_m2ms = None previous_obj = bundle.obj attr = self.attribute if isinstance(self.attribute, basestring): attrs = self.attribute.split('__') the_m2ms = bundle.obj for attr in attrs: previous_obj = the_m2ms try: the_m2ms = getattr(the_m2ms, attr, None) except ObjectDoesNotExist: the_m2ms = None if not the_m2ms: break elif callable(self.attribute): the_m2ms = self.attribute(bundle) if not the_m2ms: if not self.null: raise ApiFieldError( "The model '%r' has an empty attribute '%s' and doesn't allow a null value." % (previous_obj, attr)) return [] self.m2m_resources = [] m2m_dehydrated = [] # TODO: Also model-specific and leaky. Relies on there being a # ``Manager`` there. m2ms = the_m2ms.all() if for_list else the_m2ms.get_query_set().all() for m2m in m2ms: m2m_resource = self.get_related_resource(m2m) m2m_bundle = Bundle(obj=m2m, request=bundle.request) self.m2m_resources.append(m2m_resource) m2m_dehydrated.append(self.dehydrate_related(m2m_bundle, m2m_resource, for_list=for_list)) return m2m_dehydrated def _build_reverse_url(self, name, args=None, kwargs=None): return kwargs.get('pk') def get_via_uri(self, uri, request=None): bundle = self.build_bundle(request=request) return self.obj_get(bundle=bundle, pk=uri) def build_related_resource(self, value, request=None, related_obj=None, related_name=None): """ Returns a bundle of data built by the related resource, usually via ``hydrate`` with the data provided. Accepts either a URI, a data dictionary (or dictionary-like structure) or an object with a ``pk``. """ self.fk_resource = self.to_class() kwargs = { 'request': request, 'related_obj': related_obj, 'related_name': related_name, } if isinstance(value, Bundle): # Already hydrated, probably nested bundles. Just return. return value elif isinstance(value, (basestring, int)): # We got a URI. Load the object and assign it. return self.resource_from_uri(self.fk_resource, value, **kwargs) elif isinstance(value, Bundle): # We got a valid bundle object, the RelatedField had full=True return value elif hasattr(value, 'items'): # We've got a data dictionary. # Since this leads to creation, this is the only one of these # methods that might care about "parent" data. return self.resource_from_data(self.fk_resource, value, **kwargs) elif hasattr(value, 'pk'): # We've got an object with a primary key. return self.resource_from_pk(self.fk_resource, value, **kwargs) else: raise ApiFieldError("The '%s' field was given data that was not a URI, not a dictionary-alike and does not have a 'pk' attribute: %s." % (self.instance_name, value))

django_app /的初始化的.py

def patch_tastypie(): from tastypie.fields import ToManyField, RelatedField from tastypie.resources import Resource, ResourceOptions from monkey.tastypie import dehydrate, _build_reverse_url, get_via_uri, build_related_resource setattr(ToManyField, 'dehydrate', dehydrate) setattr(Resource, '_build_reverse_url', _build_reverse_url) setattr(Resource, 'get_via_uri', get_via_uri) setattr(ResourceOptions, 'include_resource_uri', False) setattr(RelatedField, 'build_related_resource', build_related_resource)

它并不完美，但加速from __future__ import absolute_import from .monkey import patch_tastypie patch_tastypie() 10-20％

Django Tastypie Postgres缓慢的服务器响应

1 个答案:

django_app /猴/ tastypie.py

django_app /猴/的初始化的.py

django_app /的初始化的.py