Re: [pgadmin-support] connection dropping continued

[Andreas Pflug]

Markus Wollny wrote:

Hi!

 

-----Ursprüngliche Nachricht-----
Von: Andreas Pflug [mailto:[EMAIL PROTECTED]
Gesendet: Dienstag, 17. Februar 2004 17:40
An: Josh Endries
Cc: [EMAIL PROTECTED]; Markus Wollny
Betreff: Re: [pgadmin-support] connection dropping continued
   

 

This is *not* an pgAdmin issue, any other app will suffer the same 
problem if crossing that firewall. 
   

You're absolutely right insofar as this is not _caused_ by PGAdmin III;
other apps (we're using some oldish version of SQL Navigator to connect
to an Oracle 8i DB) show the exactsame behaviour.
 

Your network is broken, contact your 
system administrator to fix the firewall. We're using libpq, which 
doesn't offer such keep-alive option, because it relies on 
TCP/IP which 
by definition delivers a solid connection, unless aborted 
deliberately 
by a malfunctioning firewall or router.
   

I wouldn't call that malfunctioning, 

So call it ill-configured.

the behaviour of the firewall is
intended and does make sense, as it would open some possibilities for
DOS-attacks if there would be no timeout.
So even though it's not caused by PGAdmin III, it could be resolved in
the application level without the need to interfere with firewalls - 

Wrong sight; the firewall is the interferer, screwing up tcpip. Simply 
let it forward according to RFCs, and everything's fine.

and
I think that there must be a lot of people who don't have sufficient
access to their firewalls or routers in order to resolve the issue
there. 

I'm not saying that this is a vital feature for PGAdmin III to have, I'm
not saying that the software is crappy because the connection times out.
All I'm saying is that some sort of keep-alive-mechanism would be a
handy feature to have in PGAdmin III. And there's really no need to
establish some complicated mechanism on the network-protocol level to
get the desired results
Wrong way; it's extra effort to *kill* the connection!

, a simple "select 1;" issued every 30 odd
seconds to all opened databases would be absolutely sufficient, I should
think. If that feature is off by default and can be switched on (and
maybe the interval adjusted according to needs), no one would be
bothered by it either.
 

We can not and thus will not implement app level keep-alives.
You can try to head over to pgsql-bugs or pgsql-hackers, to recommend 
implementing that in libpq, and you certainly will get the same answer: 
FIX THE FIREWALL!
The server is waiting for tcp/ip disconnect, which is never coming 
because the firewall eats this, resulting in backends waiting to death. 
Again: you'll have to request your sysadmin to fix the firewall, at 
least on that pgsql port for internal use. Timeouts simply don't make 
sense here. You won't have DOS attacks internally, I hope (if you do, 
locate the aggressor, and eliminate him).

Regards,
Andreas
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