quickfix-developers

[Quickfix-developers] Intermittent disconnects on Solaris

[<kri...@rb...>]

I have isolated the cause of the intermittent disconnects caused by QuickFI=
X on Solaris. The problem was due to the use of the I_NREAD ioctl to determ=
ine whether a readable socket was EOF or not.

In certain circumstances which seem to involve high network traffic and low=
 machine load, I_NREAD will return zero for a readable socket that actually=
 has data. In such cases, QuickFIX would erroneously close the socket.

I replaced the I_NREAD code in socket_disconnected() one byte recv() with t=
he MSG_PEEK flag. This appears to have resolved this rather troublesome iss=
ue for us in production.

I will send patches against 1.9.4 for this fix, as well as other changes re=
quired to get QuickFIX to compile on Solaris/SunPRO 5.3 w/Roguewave STL, af=
ter I have tested them with SunPRO and the default STL, as well as gcc on S=
olaris.

Regards,

- Kris

Utility.cpp
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
OLD
---
bool socket_disconnected( int s )
{ QF_STACK_PUSH(socket_disconnected)

  unsigned long read;
#ifdef _MSC_VER
  ioctlsocket( s, FIONREAD, &read );
#elif defined(USING_STREAMS)
  ioctl( s, I_NREAD, &read );
#else
  ioctl( s, FIONREAD, &read );
#endif
  return read =3D=3D 0;

  QF_STACK_POP
}
NEW
---
bool socket_disconnected( int s )
{ QF_STACK_PUSH(socket_disconnected)

#if defined(_MSC_VER) || !defined(USING_STREAMS)
  unsigned long read;
  #ifdef _MSC_VER
    ::ioctlsocket( s, FIONREAD, &read );
  #else
    ::ioctl( s, FIONREAD, &read );
  #endif
  return read =3D=3D 0;
#elif defined(USING_STREAMS)
  char byte;
  return ::recv (s, &byte, sizeof (byte), MSG_PEEK) <=3D 0;
#endif

  QF_STACK_POP
}


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Re: [Quickfix-developers] Intermittent disconnects on Solaris

[Caleb E. <cal...@gm...>]

On Mon, 21 Mar 2005 19:02:19 -0000, kri...@rb...
<kri...@rb...> wrote:

> I have isolated the cause of the intermittent disconnects caused by QuickFIX on Solaris. The problem was due to the use of the I_NREAD ioctl to determine whether a readable socket was EOF or not.
> 
> In certain circumstances which seem to involve high network traffic and low machine load, I_NREAD will return zero for a readable socket that actually has data. In such cases, QuickFIX would erroneously close the socket.
> 
> I replaced the I_NREAD code in socket_disconnected() one byte recv() with the MSG_PEEK flag. This appears to have resolved this rather troublesome issue for us in production.
> 

Shouldn't QuickFIX just rely on recv returning 0 to detect a socket
disconnect, instead of relying on this ioctl?  I've never seen a
socket-based application using this technique to detect disconnects
before.  Clearly its not 100% reliable.

-- 
Caleb Epstein
caleb dot epstein at gmail dot com

Re: [Quickfix-developers] Intermittent disconnects on Solaris

[Oren M. <or...@qu...>]

Yeah, I agree.

--oren

----- Original Message ----- 
From: "Caleb Epstein" <cal...@gm...>
To: <kri...@rb...>
Cc: <qui...@li...>; <Bar...@gs...>
Sent: Monday, March 21, 2005 1:20 PM
Subject: Re: [Quickfix-developers] Intermittent disconnects on Solaris


> QuickFIX Documentation: 
> http://www.quickfixengine.org/quickfix/doc/html/index.html
> QuickFIX FAQ: http://www.quickfixengine.org/wikifix/index.php?QuickFixFAQ
> QuickFIX Support: http://www.quickfixengine.org/services.html
>
> On Mon, 21 Mar 2005 19:02:19 -0000, kri...@rb...
> <kri...@rb...> wrote:
>
>> I have isolated the cause of the intermittent disconnects caused by 
>> QuickFIX on Solaris. The problem was due to the use of the I_NREAD ioctl 
>> to determine whether a readable socket was EOF or not.
>>
>> In certain circumstances which seem to involve high network traffic and 
>> low machine load, I_NREAD will return zero for a readable socket that 
>> actually has data. In such cases, QuickFIX would erroneously close the 
>> socket.
>>
>> I replaced the I_NREAD code in socket_disconnected() one byte recv() with 
>> the MSG_PEEK flag. This appears to have resolved this rather troublesome 
>> issue for us in production.
>>
>
> Shouldn't QuickFIX just rely on recv returning 0 to detect a socket
> disconnect, instead of relying on this ioctl?  I've never seen a
> socket-based application using this technique to detect disconnects
> before.  Clearly its not 100% reliable.
>
> -- 
> Caleb Epstein
> caleb dot epstein at gmail dot com
>
>
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