Re: Orphan database connections
- From: "Jeffrey Beckstrom" <jbeckstrom@xxxxxxxxx>
- To: "oracle-l-freelist" <oracle-l@xxxxxxxxxxxxx>, "Chris Taylor" <christopherdtaylor1994@xxxxxxxxx>
- Date: Thu, 05 Sep 2019 10:21:59 -0400
We tried this with a database on Windows and the problem reproduces there, so
not just a Linux database issue.
This does not happen on any of our Windows 7 PCs.
Installed a Trial version of Toad yesterday. Created a connection and then
closed the Windows. Toad correctly cleaned up after itself.
Oracle is leaning towards a client OS / Network issue since nobody else is
experiencing this. Just don't know where to look.
Chris Taylor <christopherdtaylor1994@xxxxxxxxx> 9/5/19 10:10 AM >>>
That's very puzzling what you are seeing.
So the client window did in fact close it's connection as far as it was
concerned and cleaned up the socket.
But the server allowed the socket to remain open on its side. So, it's not a
client problem and appears to be server -side.
Chris
On Thu, Sep 5, 2019, 6:55 AM Jeffrey Beckstrom <jbeckstrom@xxxxxxxxx> wrote:
Yes it was.
Chris Taylor <christopherdtaylor1994@xxxxxxxxx> 9/4/19 11:34 PM >>>
That looks like your socket died / ended on the workstation because the only
socket you have open is to port 22 after you kill the window.
Was it still open on the DB ?
Chris
On Wed, Sep 4, 2019 at 2:47 PM Jeffrey Beckstrom <jbeckstrom@xxxxxxxxx> wrote:
Before close window:
C:\WINDOWS\system32>netstat -anob |findstr -i 65237 - My putty session???
TCP zz.z.z.zzz:65237 xx.zz.zz.z:22 ESTABLISHED 13080
C:\WINDOWS\system32>netstat -anob |findstr -i 65235
TCP zz.z.z.zzz:65235 xx.xx.xx.x:1521 ESTABLISHED 12676
After close the window:
C:\WINDOWS\system32>netstat -anob |findstr -i 65237
TCP zz.z.z.zzz:65237 xx.xx.xx.x:22 ESTABLISHED 13080
C:\WINDOWS\system32>netstat -anob |findstr -i 65235
C:\WINDOWS\system32>
Chris Taylor <christopherdtaylor1994@xxxxxxxxx> 9/4/19 3:21 PM >>>
Try this:
1. Use sqlplus as your test subject
2. Open sqlplus and connect to the db on the windows 10 client
3. Open the db server do a netstat -anop | grep -i <your clients ip_address>
(you should find a port open that maps to your workstation ip)
4. Open a command prompt on your windows client and do a netstat -anob |
findstr -i port# (from step 3)
5. Close the sqlplus window (not exit the program)
6. Do another netstat -anob | findstr for the port# and check the status ... if
its in TCP_TIMEDWAIT then its a time_wait indefinite issue
... if the socket is actually dead/gone on the client, then I am at a loss
... if the socket is showing CLOSE_WAIT then you might have a tcp close wait
time issue (not sure the param that controls that on windows off top of my head
however)
Chris
On Wed, Sep 4, 2019 at 2:01 PM Jeffrey Beckstrom <jbeckstrom@xxxxxxxxx> wrote:
As a test, I installed Quest Toad (trial) and performed test. Upon closing the
Window the database connections were terminated. Could be that Toad captured
the close Window command and cleaned up after itself before terminating.
A packet trace shows Toad sending a "FIN" to the database while Oracle's
programs send a "RST" as the final transmission.
Chris Taylor <christopherdtaylor1994@xxxxxxxxx> 9/4/19 12:18 PM >>>
Tcp_timedwaitdelay indefinite perhaps?
Something in the TCP stack keeping the socket open on the clients PC
Chris
On Wed, Sep 4, 2019, 10:57 AM Jeffrey Beckstrom <jbeckstrom@xxxxxxxxx> wrote:
We are in the very early stages of a desktop migration to Windows 10. To date,
only 3 IT personnel that use Oracle have a Windows 10 PC. Of those, two are
experiencing a problem. If you are in SQL Plus or SQL Developer and do not
exit/close the connection prior to closing the application's window, the
database connection remains after the program is terminated. This does not
occur on any of our Windows 7 desktops. We have not been able to identify a
difference between the PC that does terminate the database connection upon the
window being closed and the two that do not. All of our PCs start from a
standard image.
Oracle is suggesting looking at the network, however, all of the PCs are inside
the firewall and if in SQL PLus you state "exit" or in SQL Developer you right
click the connection and choose disconnect, the connections are terminated. The
issue only arises on 2 out 3 PCs if just close the Window without taking any
other actions first.
Any suggestions on what may be the cause? Does Windows 10 not send a
termination message and thus you now have ensure you break the connection
manually?
Jeffrey Beckstrom
Lead Database Administrator
Information Technology Department
Greater Cleveland Regional Transit Authority
1240 W. 6th Street
Cleveland, Ohio 44113
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