[Spread-users] Problem with Java client

[Jarosław Nozderko]

Hi Ryan, Theo,

 thanks a lot for your responses.
I can't access CVS through SSH at the moment, so I've added manually 
setTcpNoDelay(true) in connect() and listener.join() in stopListener()
to version from 3.17.3. 

It's OK now - message is delivered, and LEAVE is reported.

However, it didn't fix another problem - when I kill Spread 
dameon, User (java test client) is not notified (spuser correctly
exits) and obviously crashes after any further attempt to communicate
(SocketException: Broken pipe).

Then I removed setTcpNoDelay(true) and replaced it with 
setSoLinger(true, x), for several x (1,10,100,1000).
It seems to be unpredictable a bit - it happened once
to work for x=1000, in general it does not. Seriously, since this is
timeout in sec



Disabling 



Regards,
Jarek 

 

> -----Wiadomość oryginalna-----
> Od: Ryan Caudy [mailto:rcaudy at gmail.com] 
> Wysłano: 18 sierpnia 2005 02:32
> Do: Theo Schlossnagle
> DW: Jarosław Nozderko; spread-users at lists.spread.org
> Temat: Re: [Spread-users] Problem with Java client
> 
> My reason for considering TCP_NODELAY is to avoid holding 
> onto data longer than necessary, hopefully leaving the buffer 
> empty when the socket is closed.  Regardless, I think it's an 
> appropriate setting for the Java API to use, the same as the C API.
> 
> From the description of SO_LINGER read after reading Theo's 
> response, we should be using it in both the Java and C APIs.  
> It seems like a more correct way to solve Jaroslaw's problem, 
> as well as a generally good thing to use regardless, 
> considering the kind of guarantees we're trying to preserve.
> 
> Cheers,
> Ryan
> 
> On 8/17/05, Theo Schlossnagle <jesus at omniti.com> wrote:
> > Ryan Caudy wrote:
> > 
> > >It sounds to me like there's some sort of buffering going 
> on in the 
> > >Java client at the socket level.
> > >
> > >If I had to guess, I would say that this is because the 
> Spread Java 
> > >API isn't using TCP_NODELAY.  The C API is, and hence wouldn't be 
> > >subject to the same problem, assuming that my hypothesis 
> is correct.
> > >
> > >Attached to this message is a patch to SpreadConnection.java 
> > >(generated against the latest CSV version) which should set this 
> > >socket option.
> > >
> > >Please let me know if this helps.
> > >
> > >
> > TCP_NODELAY effect how the socket reacts when you send data on it.  
> > Not how it reacts when you close it.
> > 
> > Look at setsockopt(.... SO_LINGER).  and in C make sure you 
> shutdown() 
> > the socket before you call close. (read the shutdown man page).
> > 
> > If you just call close() on a socket, you can certainly loose data 
> > you've written to it that has yet to be transmitted.
> > 
> > 
> http://java.sun.com/j2se/1.4.2/docs/api/java/net/Socket.html#setSoLing
> > er(boolean,%20int)
> > 
> > Best regards,
> > 
> > Theo
> >
>