现象:

某系统通过单点登录(SSO) 技术验证用户登录。用户在SSO 系统上通过验证后,跳转到某系统的主页上面。而跳转的时间很长,约1分钟以上。

分析步骤:

在问题复现时抓取Hang dump 进行分析:

1) 找到用户登陆的调用堆栈

0:071> kb

RetAddr           : Args to Child                                                           : Call Site

000007fe`f81889e5 : 00000000`0d379e30 00000000`0d379490 00000000`0d378ba0 00000000`00000000 : MSVCR100_CLR0400!memcpy+0x266

000007fe`f818915c : 00000000`0d378b70 000007fe`f8251a30 00000000`0000252c 000007fe`f398d1c8 : clr!StackFrameIterator::ProcessCurrentFrame+0x56a

000007fe`f818936a : 00000000`00000000 00000000`0d378b70 000007fe`f398d19c 00000000`0d378b70 : clr!StackFrameIterator::NextRaw+0x35c

000007fe`f8188d8c : 00000000`0d379420 00000000`00000002 00000000`00000002 00000000`0d378f40 : clr!StackFrameIterator::Next+0x22

000007fe`f826e2a7 : 00000000`0e0936d0 00000000`0e0936d0 00000000`00000000 00000000`00000000 : clr!Thread::StackWalkFramesEx+0x9e

000007fe`f83350f0 : 00006dae`0a62919f 00000000`0e0936d0 00000000`00000000 00000000`00000000 : clr!Thread::ReadyForAsyncException+0x197

000007fe`f833503b : 00000000`0e0936d0 00000000`00000028 00000000`0e0936d0 000007fe`f87cec00 : clr!Thread::HandleThreadAbort+0x6c

000007fe`f83352d7 : 00000000`00000000 00000000`037bc050 00000000`0e0936d0 000007fe`f87cece0 : clr!CommonTripThread+0x18

000007fe`f81b6615 : 000007fe`f81b6470 00000000`00000000 00000000`00001ad6 00000001`00000028 : clr!FC_GCPoll+0x107

000007fe`f398d1c8 : 00000001`5ff74050 00000000`00001296 00000001`5ff76c08 00000000`00000000 : clr!Buffer::BlockCopy+0x1a5

000007fe`f36b932a : 00006dae`d26d74e7 000007fe`f87cdfc0 00000000`0d37dce8 00000000`00000000 : System_Xml_ni!System.Xml.XmlTextReaderImpl.ShiftBuffer(Int32, Int32, Int32)+0x28

000007fe`f36b8c6d : 00000000`0d37b4d0 00000001`5ff76c08 00000014`00054cfe 000007fe`f718f13e : System_Xml_ni!System.Xml.XmlTextReaderImpl.ParseText(Int32 ByRef, Int32 ByRef, Int32 ByRef)+0x19a

000007fe`f36b8a87 : 00000002`3067ffe0 000007fe`f36c0cdb 000007fe`f37578c0 00000002`30680008 : System_Xml_ni!System.Xml.XmlTextReaderImpl.ParseText()+0x6d

000007fe`f36c02f9 : 00000001`5ff740b0 000007fe`f36bfd6d 00000001`5ff74060 00000001`5ff74050 : System_Xml_ni!System.Xml.XmlTextReaderImpl.ParseElementContent()+0x27

000007fe`f3703caa : 00000001`5ff73a30 00000002`6f9e4320 00000001`5ff74038 00000001`5ff74040 : System_Xml_ni!System.Xml.XmlLoader.LoadNode(Boolean)+0xf9

000007fe`f37036e0 : 00000001`5ff74038 00000001`5ff74040 00000001`5ff738e8 00000000`0d37b670 : System_Xml_ni!System.Xml.XmlLoader.LoadDocSequence(System.Xml.XmlDocument)+0x4a

000007fe`f370308d : 00000001`5ff738e8 00000002`7f992078 00000001`5ff738e8 00000000`0d37b6f0 : System_Xml_ni!System.Xml.XmlDocument.Load(System.Xml.XmlReader)+0x90

000007ff`004007f6 : 00000000`23a3db85 000007fe`f71f1590 00000000`00000000 00000000`00000000 : System_Xml_ni!System.Xml.XmlDocument.Load(System.String)+0xcd

000007ff`0040039c : 00000001`5ff732b0 00000002`6f9e4320 00000001`8f98ee20 80000000`00000001 : XXXXXX_Sql_Common!Common.XmlHelper.InsertNode(System.String, System.String, Boolean, System.String, System.Collections.Hashtable, System.Collections.Hashtable)+0xb6

000007ff`00400060 : 00000002`0f980e00 00000001`5ff72c48 00000001`3f98b328 000007fe`f8266279 : XXXXXX_Sql_Common!Common.ErrorLog.Insert(System.String, System.String, System.String)+0x30c

000007ff`004defbc : 00000002`0f980e00 00000001`5ff72ba8 00000001`3f98b328 00000000`0d37c2c0 : XXXXXX_Sql_Common!Common.ErrorLog.Insert(System.String, System.Exception, System.String)+0x60

000007fe`f82665ed : 00000000`0e0936d0 00000000`0e0936d0 000007ff`004def74 00000000`0d37c370 : XXXXXX_Web!EasyMail.Web.login.Page_Load(System.Object, System.EventArgs)+0x19ec

000007fe`f82663f2 : 00000000`0377e3a0 000007ff`004def74 00000000`0d37dea0 000007ff`004cbe98 : clr!ExceptionTracker::CallHandler+0x1c1

000007fe`f8266342 : 00000000`0d37dea0 00000000`0d37bc80 00000000`0377e3a0 00000000`0d37dea0 : clr!ExceptionTracker::CallCatchHandler+0x7e

00000000`76ec9d8d : 000007ff`004de400 00000000`0d37dea0 00000000`0d37c2c0 00000000`0d37bc80 : clr!ProcessCLRException+0x2d6

00000000`76eb8a2c : 00000000`0d380000 00000000`0d37c2c0 00000206`0005af30 000007fe`f81e9b05 : ntdll!RtlpExecuteHandlerForUnwind+0xd

000007fe`f82686a0 : 00000000`0d37dea0 00000000`0000bad0 00000000`0d37d960 00000000`0e0936d0 : ntdll!RtlUnwindEx+0x539

000007fe`f826865c : 00000000`00000000 00000000`0377e3a0 00000000`0d37c940 00000000`0d37dea0 : clr!ClrUnwindEx+0x40

00000000`76ec9d0d : 000007ff`004de481 00000000`0d37dea0 00000000`0d37d330 00000000`0d37c940 : clr!ProcessCLRException+0x2a0

00000000`76eb91af : 00000000`0d380000 000007fe`cd224604 00000000`0005af30 00000000`036ece50 : ntdll!RtlpExecuteHandlerForException+0xd

00000000`76eb97a8 : 00000000`0d37d960 00000000`0d37d330 00000000`00000001 00000000`00000000 : ntdll!RtlDispatchException+0x45a

000007fe`fd0b9e5d : 00000000`0e0936d0 00000000`00000001 00000000`00000001 00000000`0e0936d0 : ntdll!RtlRaiseException+0x22f

000007fe`f8266d1d : 00000000`0e0936d0 00000000`00000001 00000000`0d37dbf1 00000001`5ff72ba8 : KERNELBASE!RaiseException+0x39

000007fe`f826f91e : 00000000`0d37dbd8 00000001`5ff72ba8 00000000`0e0936d0 00000001`5ff72ba8 : clr!RaiseTheExceptionInternalOnly+0x363

000007fe`f826f76b : 00000000`ffb07948 00000000`00000001 00000000`0e0936d0 00000000`0e0936d0 : clr!Thread::UserAbort+0x19a

000007fe`f71b5929 : 00000002`7f992078 00000001`5ff72b90 00000000`00000000 00000000`00000000 : clr!ThreadNative::Abort+0x14b

000007fe`cd19b9a6 : 00000000`ffb45ad0 00000001`dfe872a8 00000001`8f98edc0 00000000`00000000 : mscorlib_ni!System.Threading.Thread.Abort(System.Object)+0x39

000007ff`004de481 : 00000002`0f980da0 00000001`dfe86a90 00000001`3f98b328 80000000`00000000 : System_Web_ni!System.Web.HttpResponse.End()+0x166

000007fe`fad79c09 : 00000001`ef9f1b18 00000001`ef9f1b18 00000001`3f98add0 00000000`0d37e680 : XXXXXX_Web!XXXXXX.Web.login.Page_Load(System.Object, System.EventArgs)+0xeb1

000007fe`cd1b9217 : 00000001`efa2bfb8 000007fe`cd19e96b 00000000`00000000 00000000`00000000 : System_Web_RegularExpressions_ni!System.Web.Util.CalliHelper.EventArgFunctionCaller(IntPtr, System.Object, System.Object, System.EventArgs)+0x19

000007fe`cd1b4d38 : 00000001`efa01d90 00000000`ffb68778 00000000`ffb68501 000007fe`cd19ad55 : System_Web_ni!System.Web.UI.Control.LoadRecursive()+0x47

000007fe`cd1b4011 : 00000001`ef9f1b18 000007fe`cd1b6601 00000000`00000001 000007fe`cd1a4f38 : System_Web_ni!System.Web.UI.Page.ProcessRequestMain(Boolean, Boolean)+0xbf8

000007fe`cd1b3ebd : 00000001`ef9f1b18 00000002`7f9980a0 00000000`ffb68501 00000000`00000004 : System_Web_ni!System.Web.UI.Page.ProcessRequest(Boolean, Boolean)+0xc1

000007fe`cd1b2cb7 : 00000001`ef9f1b18 000007fe`cd19fc2a 000007ff`00143cf0 000007fe`cd1bc313 : System_Web_ni!System.Web.UI.Page.ProcessRequest()+0x10d

000007ff`004dc5e3 : 00000000`0d37e850 00000001`efa01d90 00000000`ffb683c0 00000000`0d37e8d0 : System_Web_ni!System.Web.UI.Page.ProcessRequest(System.Web.HttpContext)+0xa7

000007fe`cd1bc7a1 : 00000001`ef9f1b18 00000000`ffb45810 00000001`3fa5bb88 00000000`00000000 : App_Web_0khihdrb!ASP.login_aspx.ProcessRequest(System.Web.HttpContext)+0x33

000007fe`cd1891fe : 00000000`ff9c0001 00000000`ffa11980 00000000`ffb683c0 00000000`00000001 : System_Web_ni!System.Web.HttpApplication+CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()+0x271

000007fe`cd19d49a : 00000001`3fa59cc8 00000001`3fa5bc50 00000000`0d37eab0 000007fe`cd29fd68 : System_Web_ni!System.Web.HttpApplication.ExecuteStep(IExecutionStep, Boolean ByRef)+0x10e

000007fe`cd1886e1 : 00000001`3fa5b9a0 00000000`00000000 00000002`7f9980a0 00000000`0d37ebb0 : System_Web_ni!System.Web.HttpApplication+ApplicationStepManager.ResumeSteps(System.Exception)+0x20a

000007fe`cd18d6ae : 01ce7e07`d83d1609 00000000`ffa6e3b8 00000000`00000000 00000000`00000004 : System_Web_ni!System.Web.HttpApplication.System.Web.IHttpAsyncHandler.BeginProcessRequest(System.Web.HttpContext, System.AsyncCallback, System.Object)+0xf1

000007fe`cd18c377 : 00000000`ff9bf918 00000000`ffb44b30 00000000`0d37ebf0 00000000`00000000 : System_Web_ni!System.Web.HttpRuntime.ProcessRequestInternal(System.Web.HttpWorkerRequest)+0x26e

000007fe`cd90f80d : 00000000`ffa68ed8 00000000`00000000 000007fe`f71ab630 000007fe`f87ce8b0 : System_Web_ni!System.Web.Hosting.ISAPIRuntime.ProcessRequest(IntPtr, Int32)+0x1c7

000007fe`f8249b9e : 00000000`0124fda0 00000000`01338310 00000000`00000002 00000000`0d37f330 : System_Web_ni!DomainNeutralILStubClass.IL_STUB_COMtoCLR(Int64, Int32, Int32 ByRef)+0x1d

000007fe`f8249782 : 00000000`0383a7d0 000007fe`f81e8244 00000000`0d37f0a8 00000000`00000000 : clr!COMToCLRDispatchHelper+0x4e

000007fe`f8249686 : 00000000`00000000 000007fe`cd11a308 00000000`ffa68ed8 00000000`0d37f2d0 : clr!COMToCLRWorkerBody+0x1ca

000007fe`f82495a2 : 00000000`00000002 00000000`00000000 00000000`0d37f3f0 00000000`00000000 : clr!COMToCLRWorkerBody+0xd6

000007fe`f8249e85 : 00000000`00000000 00000000`037733f0 00000000`00000002 00000000`00000000 : clr!COMToCLRWorkerDebuggerWrapper+0x22

000007fe`f8249b47 : 00000000`0e0936d0 00000000`0d37f2d0 00000000`012d8400 00000000`00000001 : clr!COMToCLRWorker+0x44b

000007fe`e1f122d6 : 00000000`0124fda0 00000000`01338310 00000000`00000002 00000000`0d37f330 : clr!GenericComCallStub+0x57

000007fe`e1f12e06 : 00000000`00000001 00000000`0e91aa10 00000000`00000000 00000000`0d37f950 : webengine4!HttpCompletion::ProcessRequestInManagedCode+0x1e8

000007fe`e1f12dc3 : 00000000`01338310 00000000`00000000 ffffffff`fffffffe 00000000`00000000 : webengine4!HttpCompletion::ProcessCompletion+0x5c

000007fe`f82413d5 : 000007fe`e1f12da0 00000000`0d37f870 00000000`00000000 000007fe`f89cdfa0 : webengine4!CorThreadPoolWorkitemCallback+0x24

000007fe`f8240908 : 00000000`0e0936d0 00000000`00000001 00000000`00000000 00000000`d73646db : clr!UnManagedPerAppDomainTPCount::DispatchWorkItem+0x181

000007fe`f834b7bf : 00000000`00000001 00000000`0ecd3c01 00000002`00000804 00000003`001a001a : clr!ThreadpoolMgr::NewWorkerThreadStart+0x2e5

000007fe`f8349b56 : 00000000`00000000 00000000`00000000 00000000`00000000 00000000`00000000 : clr!ThreadpoolMgr::WorkerThreadStart+0x3b

00000000`76d9652d : 00000000`00000000 00000000`00000000 00000000`00000000 00000000`00000000 : clr!Thread::intermediateThreadProc+0x7d

00000000`76ecc521 : 00000000`00000000 00000000`00000000 00000000`00000000 00000000`00000000 : kernel32!BaseThreadInitThunk+0xd

00000000`00000000 : 00000000`00000000 00000000`00000000 00000000`00000000 00000000`00000000 : ntdll!RtlUserThreadStart+0x1d

在堆栈中,以上标红的部分有一个Thread.Abort() 调用,这会引发TheadAbortException 异常的抛出。

2) 提取异常对象进行查看:

0:071> !do 00000001`5ff72ba8

Name:        System.Threading.ThreadAbortException

MethodTable: 000007fef72b6ef0

EEClass:     000007fef6df1860

Size:        160(0xa0) bytes

File:        C:\Windows\Microsoft.Net\assembly\GAC_64\mscorlib\v4.0_4.0.0.0__b77a5c561934e089\mscorlib.dll

Fields:

MT    Field   Offset                 Type VT     Attr            Value Name

000007fef72b6738  400004b        8        System.String  0 instance 0000000000000000 _className

000007fef72b7760  400004c       10 ...ection.MethodBase  0 instance 0000000000000000 _exceptionMethod

000007fef72b6738  400004d       18        System.String  0 instance 0000000000000000 _exceptionMethodString

000007fef72b6738  400004e       20        System.String  0 instance 000000015ff72c48 _message

000007fef72d9bc8  400004f       28 ...tions.IDictionary  0 instance 0000000000000000 _data

000007fef72b6b00  4000050       30     System.Exception  0 instance 0000000000000000 _innerException

000007fef72b6738  4000051       38        System.String  0 instance 0000000000000000 _helpURL

000007fef72b5890  4000052       40        System.Object  0 instance 000000015ff72d50 _stackTrace

000007fef72b5890  4000053       48        System.Object  0 instance 0000000000000000 _watsonBuckets

000007fef72b6738  4000054       50        System.String  0 instance 0000000000000000 _stackTraceString

000007fef72b6738  4000055       58        System.String  0 instance 0000000000000000 _remoteStackTraceString

000007fef72bc620  4000056       88         System.Int32  1 instance                0 _remoteStackIndex

000007fef72b5890  4000057       60        System.Object  0 instance 0000000000000000 _dynamicMethods

000007fef72bc620  4000058       8c         System.Int32  1 instance      -2146233040 _HResult

000007fef72b6738  4000059       68        System.String  0 instance 0000000000000000 _source

000007fef72c3318  400005a       78        System.IntPtr  1 instance                0 _xptrs

000007fef72bc620  400005b       90         System.Int32  1 instance       -532462766 _xcode

000007fef72b6248  400005c       80       System.UIntPtr  1 instance      7fef71b5929 _ipForWatsonBuckets

000007fef72eb600  400005d       70 ...ializationManager  0 instance 000000015ff72c70 _safeSerializationManager

0:071> !do 000000015ff72c48

Name:        System.String

MethodTable: 000007fef72b6738

EEClass:     000007fef6e3ed68

Size:        40(0x28) bytes

File:        C:\Windows\Microsoft.Net\assembly\GAC_64\mscorlib\v4.0_4.0.0.0__b77a5c561934e089\mscorlib.dll

String:      正在中止线程。

Fields:

MT    Field   Offset                 Type VT     Attr            Value Name

000007fef72bc620  4000103        8         System.Int32  1 instance                7 m_stringLength

000007fef72bb160  4000104        c          System.Char  1 instance             6b63 m_firstChar

000007fef72b6738  4000105       10        System.String  0   shared           static Empty

>> Domain:Value  00000000037733f0:000000015f980488 000000000383a7d0:000000015f980488 <<

3) 根据堆栈显示,异常对象抛出之后,被程序代码捕获并通过XXXXXX_Sql_Common!Common.ErrorLog.Insert() 记录下来:

000007fe`f398d1c8 : 00000001`5ff74050 00000000`00001296 00000001`5ff76c08 00000000`00000000 : clr!Buffer::BlockCopy+0x1a5

000007fe`f36b932a : 00006dae`d26d74e7 000007fe`f87cdfc0 00000000`0d37dce8 00000000`00000000 : System_Xml_ni!System.Xml.XmlTextReaderImpl.ShiftBuffer(Int32, Int32, Int32)+0x28

000007fe`f36b8c6d : 00000000`0d37b4d0 00000001`5ff76c08 00000014`00054cfe 000007fe`f718f13e : System_Xml_ni!System.Xml.XmlTextReaderImpl.ParseText(Int32 ByRef, Int32 ByRef, Int32 ByRef)+0x19a

000007fe`f36b8a87 : 00000002`3067ffe0 000007fe`f36c0cdb 000007fe`f37578c0 00000002`30680008 : System_Xml_ni!System.Xml.XmlTextReaderImpl.ParseText()+0x6d

000007fe`f36c02f9 : 00000001`5ff740b0 000007fe`f36bfd6d 00000001`5ff74060 00000001`5ff74050 : System_Xml_ni!System.Xml.XmlTextReaderImpl.ParseElementContent()+0x27

000007fe`f3703caa : 00000001`5ff73a30 00000002`6f9e4320 00000001`5ff74038 00000001`5ff74040 : System_Xml_ni!System.Xml.XmlLoader.LoadNode(Boolean)+0xf9

000007fe`f37036e0 : 00000001`5ff74038 00000001`5ff74040 00000001`5ff738e8 00000000`0d37b670 : System_Xml_ni!System.Xml.XmlLoader.LoadDocSequence(System.Xml.XmlDocument)+0x4a

000007fe`f370308d : 00000001`5ff738e8 00000002`7f992078 00000001`5ff738e8 00000000`0d37b6f0 : System_Xml_ni!System.Xml.XmlDocument.Load(System.Xml.XmlReader)+0x90

000007ff`004007f6 : 00000000`23a3db85 000007fe`f71f1590 00000000`00000000 00000000`00000000 : System_Xml_ni!System.Xml.XmlDocument.Load(System.String)+0xcd

000007ff`0040039c : 00000001`5ff732b0 00000002`6f9e4320 00000001`8f98ee20 80000000`00000001 : EasyMail_Sql_Common!Common.XmlHelper.InsertNode(System.String, System.String, Boolean, System.String, System.Collections.Hashtable, System.Collections.Hashtable)+0xb6

000007ff`00400060 : 00000002`0f980e00 00000001`5ff72c48 00000001`3f98b328 000007fe`f8266279 : EasyMail_Sql_Common!Common.ErrorLog.Insert(System.String, System.String, System.String)+0x30c

000007ff`004defbc : 00000002`0f980e00 00000001`5ff72ba8 00000001`3f98b328 00000000`0d37c2c0 : EasyMail_Sql_Common!Common.ErrorLog.Insert(System.String, System.Exception, System.String)+0x60

000007fe`f82665ed : 00000000`0e0936d0 00000000`0e0936d0 000007ff`004def74 00000000`0d37c370 : EasyMail_Web!EasyMail.Web.login.Page_Load(System.Object, System.EventArgs)+0x19ec

000007fe`f82663f2 : 00000000`0377e3a0 000007ff`004def74 00000000`0d37dea0 000007ff`004cbe98 : clr!ExceptionTracker::CallHandler+0x1c1

4) 通过进一步检查,发现记录日志的文件在D:\XXXX\SysLog\ErrorLog.XML

0:071> !do 00000002`6f9e4320

Name:        System.String

MethodTable: 000007fef72b6738

EEClass:     000007fef6e3ed68

Size:        86(0x56) bytes

File:        C:\Windows\Microsoft.Net\assembly\GAC_64\mscorlib\v4.0_4.0.0.0__b77a5c561934e089\mscorlib.dll

String:      D:\XXXX\SysLog\ErrorLog.XML

Fields:

MT    Field   Offset                 Type VT     Attr            Value Name

000007fef72bc620  4000103        8         System.Int32  1 instance               30 m_stringLength

000007fef72bb160  4000104        c          System.Char  1 instance               44 m_firstChar

000007fef72b6738  4000105       10        System.String  0   shared           static Empty

>> Domain:Value  00000000037733f0:000000015f980488 000000000383a7d0:000000015f980488 <<

原因分析:

通过以上分析步骤,可以了解到代码的执行流程大致如下:

a) XXXXXX_Web!XXXXXX.Web.login.Page_Load() 在执行HttpWebResponse.End() 时抛出了ThreadAbortException 异常;

b) 该异常抛出后被程序代码捕获;

c) 捕获的异常信息通过XXXXXX_Sql_Common!Common.ErrorLog.Insert() 方法写入到位于D:\XXXX\SysLog\ErrorLog.XML 的文件中;

首先,页面在执行代码时抛出异常就是不正确的。通过查询KB 了解到,这是一个已知问题:

http://support.microsoft.com/kb/312629

KB 中已经给出了不抛出异常的方法,即使用Response.Redirect() 方法的一个重载:

Response.Redirect(url, false);

其次,通过提取服务器上的日志文件,我们发现这个文件较大,约15MB。通过实际编写程序测试,在这个文件中插入一个异常信息,耗时较多:

这个15MB 的XML 文件在打开,保存是耗时较长。

结论:

由于登录页面在SSO 登录时采用了不恰当的页面跳转方法,导致页面抛出ThreadAbortException 异常,并引发页面打开一个体积较大的XML 文件进行读写。最终导致了页面跳转非常缓慢的现象。尤其是在多人同时访问时,导致了对XML 日志文件的争用。导致用户并发访问量越大,跳转速度越慢。

修复建议:

1) 使用Respons.Redirect(uri, false); 实现页面跳转;

2) 使用普通文本格式记录日志替代XML 格式,以便提高速度;

3) 使用Log4Net 等成熟日志组件记录日志;

随机推荐

  1. MySQL中文全文索引插件 mysqlcft 1.0.0 安装使用文档[原创]

    [文章+程序 作者:张宴 本文版本:v1.0 最后修改:2008.07.01 转载请注明原文链接:http://blog.zyan.cc/post/356/] MySQL在高并发连接.数据库记录数较多 ...

  2. Android之网络请求库

    自己学习android也有一段时间了,在实际开发中,频繁的接触网络请求,而网络请求的方式很多,最常见的那么几个也就那么几个.本篇文章对常见的网络请求库进行一个总结. HttpUrlConnection ...

  3. SVG关注复杂图形的网页绘制技术

    SVG 是使用 XML 来描述二维图形和绘图程序的语言. 学习之前应具备的基础知识: 继续学习之前,你应该对以下内容有基本的了解: HTML XML 基础 如果希望首先学习这些内容,请在本站的首页选择 ...

  4. Javascript DOM 01 基础篇

    DOM基础   DOM是什么        答:文件对象模型(Document Object Model,简称DOM),DOM可以以一种独立于平台和语言的方式访问和修改一个文档的内容和结构!来自网络 ...

  5. idea2015的使用心得

    今天打开myeclipse感觉里面全是project,也懒着换地方了,因为这些代码还要时常看,索性安装了idea试试水,感觉还不错,用起来并不比myeclipse差,跟webstorm差不多,他俩就是 ...

  6. Memcached安装使用教程及常见问题

    一.Windows下安装memcahed 1.下载memcache的windows稳定版,解压放某个盘下面,比如在c:/memcached2.在终端(也即cmd命令界面)下输入"c:/mem ...

  7. RequireJS中的require返回模块

    requirejs中定义AMD模块规则如下: define(function(){ var ProductManager={ Create:function(){ console.log(" ...

  8. 第十八节、基于传统图像处理的目标检测与识别(HOG+SVM附代码)

    其实在深度学习中我们已经介绍了目标检测和目标识别的概念.为了照顾一些没有学过深度学习的童鞋,这里我重新说明一次:目标检测是用来确定图像上某个区域是否有我们要识别的对象,目标识别是用来判断图片上这个对象 ...

  9. FM算法(二):工程实现

    主要内容: 实现方法 Python实现FM算法 libFM   一.实现方法 1.FM模型函数 变换为线性复杂度的计算公式: 2.FM优化目标 根据不同的应用,FM可以采用不同的损失函数loss fu ...

  10. thinkphp5 composer

    前提:已安装composer 1.安装包 https://packagist.org/?query=thinkphp ,tp的各种安装包 2.安装 //安装命令, composer create-pr ...