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Re: tnsnames and sqlnet connectivity question

From: Tim Gorman <>
Date: Sat, 26 Oct 2002 08:08:48 -0800
Message-ID: <>

tnsnames and sqlnet connectivity questionThe socket 6521 cannot be active on "apollo", so you'll either have to take the TNS Listener down along with the instance or restart the TNS Listener so that it is not listening on that socket after taking the instance down. Taking the entire "apollo" machine down is another way to accomplish this... :-)

It seems reasonable that the TNS Listener should have functionality to fail immediately (or there should be a configurable timeout) with some kind of error message if the desired database instance isn't available, but it doesn't seem to work that way.

The "listener.ora" parameter CONNECT_TIMEOUT_<lsnr-name> seems like it should be a good candidate for this, but instead it seems to be a timer in the TNS Listener that starts when a connection request first starts and ends when connection is established. In other words, it is a protection mechanism against slow clients or slow WANs tying up the TNS Listener process on each connection attempt, establishing an upper-limit in which to completely establish a connection. The default value of "0" seconds means "indefinite". Unfortunately, this all doesn't seem to translate into functionality where the TNS Listener process "times itself out" if it can't establish the connection within a certain period, oddly enough...

C'est la vie...

  suppose I have an entry like this in tnsnames.ora ...

(ADDRESS = (PROTOCOL = TCP)(HOST = apollo)(PORT = 6521))
(ADDRESS = (PROTOCOL = TCP)(HOST = aquarius)(PORT = 6521))

  I try to connect to ESSNCS and (assume) apollo instance is down, it seems   sqlnet takes a long time to see if it will connect to apollo and then   connect to aquarius. But if apollo machine is down (i.e. no network   connectivity), it promptly goes to aquarius.

  How can we reduce the time that sqlnet waits to make a connection to apollo   and immediately goes to aquarius? I'd like that time to be about 5 to 6   seconds ...


  Rajendra Jamadagni MIS, ESPN Inc.   Rajendra dot Jamadagni at ESPN dot com   Any opinion expressed here is personal and doesn't reflect that of ESPN Inc.   QOTD: Any clod can have facts, but having an opinion is an art!
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Author: Tim Gorman

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Received on Sat Oct 26 2002 - 11:08:48 CDT

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