Re: long logon times through sqlnet

From: Mark Brinsmead <>
Date: Wed, 1 Apr 2009 19:50:31 -0600
Message-ID: <>

Don't ask me. Ask the Original Poster. :-)

As far as DNS is concerned, I was actually thinking of the DNS (client) software on the database server, not on the client workstation. Although * either* could be a potential candidate.

The client needs to look up the IP address for the database server; the database server needs to reverse-lookup the host name of the client (from its IP). Commonly DNS is configured with 2 or more servers, which are queried in a fixed order. If the "primary" DNS server used at either end is offline (or unreachable) you will experience a long timeout, typically in the range of 15 to 45 seconds, before your DNS client tries the secondary server.

For the DNS theory to hold any weight, the 30 second timeouts experienced by the O.P. would have to be very consistent, although, if somebody is shutting down and restarting DNS servers, you could see consistent 30 second timeouts for a few minutes or hours, followed by a return to normal.

Anyway, its only a guess, and -- as I said before -- far from the only possible explanation for the reported symtpoms.

On Mon, Mar 30, 2009 at 9:59 PM, Amar Kumar Padhi <>wrote:

> Mark,
> some basic listener Qs -
> Is the database and listener on the same server?
> Is the connect time always 30 secs, or it is intermittently happening?
> On the server itself, what happens if you log in as non-sys user with full
> alias (abc/abc_at_test), does it still take time?
> On one of the client pc, remove server name and put the server Ipaddress
> address in tnsnames.ora and try (to bypass DNS), does still take time?
> Thanks
> Amar
> -original message-
> Subject: Re: long logon times through sqlnet
> From: "Mark Brinsmead" <>
> Date: 31-03-2009 06:58
> 30 seconds? Sounds a lot like a DNS timeout.
> From the database server, are you able to reverse-lookup the IP of the
> server you are logging in from?
> Of course, this is only a guess -- there are many other possible causes.
> On Mon, Mar 30, 2009 at 9:38 AM, Dba DBA <
> >wrote:
> > Oracle 10.1.latest patch
> > OS: Tru 64
> >
> > oracle does not have 10.2 for tru 64.
> >
> > This just started to happen. We have not changed anything. If we login
> from
> > the command line on the server and bypass sqlnet logon time is normal. If
> we
> > go through the listener logon time is 30 seconds. We are not out of
> memory
> > or at any resource limits. We have a ticket with Oracle but they are
> > pointing all over the place.
> >
> > for some reason they have not asked for a sqlnet trace. I just got one
> and
> > I don't see anything in it so I am sending it to support. I ran an AWR
> > report and do not see any waits outside the norm. This tells me that the
> > issue is happening before you get to the database. so it is a listener
> > issue.
> >
> > is there any other type of trace I should run? OS level? Or log file to
> > look at to help diagnose this?
> >
> --
> Cheers,
> -- Mark Brinsmead
> Senior DBA,
> The Pythian Group

-- Mark Brinsmead
  Senior DBA,
  The Pythian Group

Received on Wed Apr 01 2009 - 20:50:31 CDT

Original text of this message