RE: SQL*Net - Connection Timeout

From: Justin Cave (DDBC) <>
Date: Fri, 29 Feb 2008 16:26:26 -0700
Message-ID: <FF249C724A53714DBE741B2AAF8CA346012DBE61@EXCHANGE.ddbc.local>

I believe that the timeout is controlled at the TCP/IP level.

Can you look at the problematic machine and see if someone has decided to be clever an muck with the default TCP/IP settings? For example, lots of logic is based on the TcpInitialRTT parameter, which includes the warning

"This parameter controls the initial time-out used for a TCP connection request and initial data retransmission on a per-interface basis. Use caution when tuning with this parameter because exponential backoff is used. Setting this value to larger than 3 results in much longer time-outs to nonexistent addresses."

Justin Cave
Distributed Database Consulting, Inc.

[] On Behalf Of Moore, Paul Sent: Friday, February 29, 2008 11:16 AM To:
Subject: SQL*Net - Connection Timeout

I have a problem with a remote database, where any attempt to connect to that database from one particular client hangs indefinitely (more precisely, for longer than I have been willing to wait to see if it's actually "hours" rather than "forever" :-)) The inability to connect from this particular client isn't a major problem, but having jobs which attempt to connect hang indefinitely rather than fail with a TNS timeout error is.
I have looked through the SQL*Net reference, and asked colleagues, but I cannot find any way of setting a parameter to say that the client (OCI, actually Python with cx_Oracle) connection should timeout after XXX seconds, regardless. Is there such a setting anywhere? The connection attempt is part of a long-running process, so I cannot simply kill the hung process. Running the connection in a thread and giving up waiting after a timeout sort of works, but the thread stays there, hung, and as time goes on the process accumulates hung threads. I'd really, really like to avoid having to re-engineer my process to spawn subprocesses for each connection (especially as this is on Windows where spawning subprocesses is a bit of a pain compared to using threads).
Has anyone got any suggestions?
Paul Moore
Oracle DBA Support
Atos Origin UK Ltd
Daresbury Court
Tel: +44 (0)1928 598537


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Received on Fri Feb 29 2008 - 17:26:26 CST

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