RE: Dead Connect detect
- From: "Bobak, Mark" <Mark.Bobak@xxxxxxxxxxxx>
- To: "Richard.Goulet@xxxxxxxxxxx" <Richard.Goulet@xxxxxxxxxxx>, "Jorgensen, Finn" <Finn.Jorgensen@xxxxxxxxxxxxxxxxx>, "oracle-l@xxxxxxxxxxxxx" <oracle-l@xxxxxxxxxxxxx>
- Date: Mon, 4 Apr 2011 13:00:01 -0400
Ok, well, I don't see a question in #1.
As to #2, DCD can work in one of two ways. Given a set firewall timeout value,
you can set SQLNET.EXPIRE_TIME to a value less than your firewall timeout, and
it will function as a keepalive. That is, connections will be preserved, or,
kept alive. On the other hand, if you *want* the connections to get whacked
after the firewall timeout, then set SQLNET.EXPIRE_TIME to something slightly
longer than your firewall timeout period, and DCD works more as it's named.
That is, it will detect the dead connections, and clean them up.
Hope that helps,
-Mark
From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On
Behalf Of Goulet, Richard
Sent: Monday, April 04, 2011 11:21 AM
To: Jorgensen, Finn; oracle-l@xxxxxxxxxxxxx
Subject: RE: Dead Connect detect
OK, I've two questions:
1) I'm using Redhat Linux
2) I don't want the firewall settings to be exceeded so sending a packet
just to keep the connection open is not desired. What is is to find those that
are dead & clean up on the Oracle side.
Dick Goulet
Senior Oracle DBA/NA Team Leader
________________________________
From: Jorgensen, Finn [mailto:Finn.Jorgensen@xxxxxxxxxxxxxxxxx]
Sent: Monday, April 04, 2011 10:07 AM
To: Goulet, Richard; 'oracle-l@xxxxxxxxxxxxx'
Subject: RE: Dead Connect detect
Dick,
Gwen Shapira did a presentation at Hotsos 2011 that involved this type of
scenario. 2 of the proposed solutions were as follows (copy and paste from her
presentation) :
Another solution will be to modify kernel parameter net.ipv4.tcp_keepalive_time
to a value lower than the firewall timeout values. This should give the TCP
keepalive a chance to keep the connection alive.
A third solution can be to use SQLNET keep-alive parameter
SQLNET.EXPIRE_TIME that allows Oracle to send its own keep-alive probes
from the server to the client, normally sent every 10 minutes. These probes will
also keep the connection a live and not allow the firewall to disconnect it.
Thanks,
Finn
From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On
Behalf Of Goulet, Richard
Sent: Monday, April 04, 2011 9:52 AM
To: oracle-l@xxxxxxxxxxxxx
Subject: Dead Connect detect
All,
Many years ago (version 9.2) I toyed with this capability of SQL*Net
without much luck. Has anyone toyed with it in recent times (11.1.0.7) with
much success??? I'm facing an issue where we have web servers in a DMZ that
connect back to the database and the firewall has a 24 hour idle timeout, so I
end up having to manually disconnect some sessions every day.
Dick Goulet
Senior Oracle DBA/NA Team Leader
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