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From: KK CHN <kkchn.in@gmail.com>
Date: Fri, 4 Oct 2024 09:59:33 +0530
Message-ID: <CAKgGyB91QVCOFp+3vAcMDAauAPQ+TOVWrJxwcVAtYxaLxXaz4Q@mail.gmail.com>
Subject: CLOSE_WAIT pileup and Application Timeout
To: pgsql-general <pgsql-general@postgresql.org>
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List,

I am facing a  network (TCP IP connection closing issue) .

Running a  mobile tablet application, Android application to update the
status of vehicles fleet say around 1000 numbers installed with the app on
each vehicle along  with a  vehicle tracking  application server solution
based on Java and Wildfly with  PosrgreSQL16 backend.

The mobile tablets are installed with the android based vehicle
tracking app which updated every 30 seconds its location fitted inside the
vehicle ( lat long coordinates) to the PostgreSQL DB through the java
backend application to know the latest location of the vehicle and its
movement which will be rendered in a map based front end.

The vehicles on the field communicate  via 443 to   8080 of the Wildfly
(version 27 ) deployed with the vehicle tracking application developed with
Java(version 17).


*  The mobile tablet communicates to the backend application over mobile
data (4G/5G SIMS). *

The  running vehicles may disconnect  or be unable to send the location
data in between if the mobile data coverage is less or absent in a
particular area where data coverage is nil or signal strength less.

The server on which the backend application runs most often ( a week's
time  or so) shows connection timeout and is unable to serve tracking  of
the vehicles further.

When we restart the  Wildfly server  the application returns to normal.
again the issue repeats  after a week or two.

In the Server machine when this bottleneck occurs  I am seeing  a lot of
TCP/IP CLOSE_WAIT   ( 3000 to 5000 ) when the server backend becomes
unresponsive.

What is the root cause of this issue ?   Is it due to the android
application unable to send the CLOSE_WAIT ACK due to poor mobile data
connectivity ?


 If so, how do people  address this issue ?  and what may be a fix ?

 Any  directions / or reference material most welcome.

Thank you,
Krishane

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<div dir=3D"ltr">List,<div><br></div><div>I am facing a=C2=A0 network (TCP =
IP connection closing issue) .</div><div><br></div><div>Running a=C2=A0 mob=
ile tablet application, Android application to update the status of vehicle=
s fleet say around 1000 numbers installed with the app on each vehicle alon=
g=C2=A0 with a=C2=A0 vehicle tracking=C2=A0 application server solution bas=
ed on Java and Wildfly with=C2=A0 PosrgreSQL16=C2=A0backend.</div><div><br>=
</div><div>The mobile tablets are installed with the android=C2=A0based veh=
icle tracking=C2=A0app which updated every 30 seconds its location fitted i=
nside the vehicle ( lat long coordinates) to the PostgreSQL DB through the =
java=C2=A0 backend application to know the latest location of the vehicle a=
nd its movement which will be rendered in a map based front end.=C2=A0</div=
><div><br></div><div>The vehicles on the field communicate=C2=A0 via 443 to=
=C2=A0 =C2=A08080 of the Wildfly (version 27 ) deployed with the vehicle tr=
acking application=C2=A0developed with Java(version 17).</div><div><br></di=
v><div><br></div><div><b>=C2=A0 The mobile tablet communicates to the backe=
nd application over mobile data (4G/5G SIMS).=C2=A0</b></div><div><br></div=
><div>The=C2=A0=C2=A0running vehicles may disconnect=C2=A0 or be unable to =
send the location data in between if the mobile data coverage is less or ab=
sent in a particular area where data coverage is nil or signal strength=C2=
=A0less.=C2=A0</div><div><br></div><div>The server on which the backend app=
lication runs most often (=C2=A0a week&#39;s time=C2=A0 or so) shows connec=
tion timeout and is unable to serve tracking=C2=A0 of=C2=A0 the vehicles fu=
rther.</div><div><br></div><div>When we restart the=C2=A0 Wildfly server=C2=
=A0 the application returns to normal.=C2=A0 again the issue repeats=C2=A0 =
after a week or two.=C2=A0</div><div><br></div><div>In the Server machine w=
hen this bottleneck occurs=C2=A0 I am seeing=C2=A0 a lot of=C2=A0 TCP/IP CL=
OSE_WAIT=C2=A0 =C2=A0( 3000 to 5000 ) when the server backend becomes unres=
ponsive.=C2=A0</div><div><br></div><div>What is the root cause of this issu=
e ?=C2=A0 =C2=A0Is it due to the android application unable to send the CLO=
SE_WAIT ACK due to poor mobile data connectivity ?=C2=A0</div><div><br></di=
v><div><br></div><div>=C2=A0If so, how do people=C2=A0 address this issue ?=
=C2=A0 and what may be a fix ?=C2=A0=C2=A0</div><div><br></div><div>=C2=A0A=
ny=C2=A0 directions / or reference material most welcome.=C2=A0</div><div><=
br></div><div>Thank you,</div><div>Krishane</div><div><br></div><div><br></=
div><div><br></div><div><br></div><div><br></div></div>

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