Re: [Fwd: Re: JDBC driver bug?]

I can confirm that this is an issue in JDK 1.5 (a/k/a Java5) in
Windows. This is not the fault of postgres, but like others have
suggested, it is with reverse DNS lookup. It affects all TCP
connections.

If you connect to an IP address it attempts to look up the name,
resulting in these delays. To confirm, add the ip address with
some name to the hosts file, normally in the
system32\drivers\etc directory under your main windows
directory.

-Kevin


>>> Csaba Nagy <nagy(at)ecircle-ag(dot)com> 09/22/05 9:46 AM >>>
I'm forwarding this to the list too. It's best to hit "reply to all"
when replying to mails to the postgres lists...

-----Forwarded Message-----
From: Csaba Nagy <nagy(at)ecircle-ag(dot)com>
To: yoursoft(at)freemail(dot)hu <yoursoft(at)freemail(dot)hu>
Subject: Re: [JDBC] JDBC driver bug?
Date: Thu, 22 Sep 2005 16:42:30 +0200

OK, in this case you might have a problem of reverse DNS. Depending on
how the JDBC driver is using the Java networking code it might happen
that Java tries to look up the host name for the IP.

In any case if there's different behavior when you run locally against
when you run from another host on the network, it is quite obviously
network related.

Try to use the host name instead of the IP and make sure the IP can be
resolved locally (on linux put it in /etc/hosts, on Windows in lmhosts I
guess, but I didn't touch a windows for quite long time).

HTH,
Csaba.

On Thu, 2005-09-22 at 16:23, yoursoft(at)freemail(dot)hu wrote:
> Dear Csaba,
>
> Thanks, for you fast answer.
> I use the following format of the connection: con =
> DriverManager.getConnection("jdbc:postgresql://10.1.1.1/dbname", "user",
> "pwd");
> I think with the direct IP address not need to use the DNS server. It is
> true?
>
> Regards,
> Ferenc
>
> Csaba Nagy wrotte:
>
> >This kind of problems usually are caused by your network/networking code
> >and not postgres itself. I bet there's some DNS resolution overhead and
> >the different java versions you're using have different DNS
> >resolution/caching policies. I would take a look at DNS as a first
> >suspect.
> >
> >HTH,
> >Csaba.
> >
> >
> >On Thu, 2005-09-22 at 15:25, yoursoft(at)freemail(dot)hu wrote:
> >
> >
> >>Dear Developers,
> >>
> >>First, sorry my bad English.
> >>My platform:
> >>- postgresql 8.0.3 and 8.0.0 with SuSE Linux.
> >>- java 1.5 update 4 (problem with it), java 1.4.2 (working without problem)
> >>- jdbc 3 driver 312 (latest stable)
> >>
> >>I found the following problem:
> >>If I connect to the database from local host with java 1.5, or with java
> >>1.4.2 from other box everything is good (connection time <1 sec).
> >>When I connect to the database on other box, there is slow connection
> >>(5-6 sec).
> >>
> >>If you have any other question, please mail it.
> >>
> >>Regards,
> >> Ferenc