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From: Francesco Benetton <frabe1579@gmail.com>
Date: Fri, 4 Oct 2024 13:41:16 +0200
Message-ID: <CACJJLizTMX=yYfScuoPZ0=tfh5wdd3P09pSYnBu+Bsh6C6=CLw@mail.gmail.com>
Subject: Re: CLOSE_WAIT pileup and Application Timeout
To: KK CHN <kkchn.in@gmail.com>
Cc: pgsql-general <pgsql-general@postgresql.org>
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If I understand clearly, postgresql is used as a Data server for the
backend, and so the Android app does not connect directly to postgresql.
The first idea is a problem on closing or recycling the connection by the
backend after executing the request. Maybe wrong client connection pooling
settings?

Il ven 4 ott 2024, 06:29 KK CHN <kkchn.in@gmail.com> ha scritto:

> 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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<p dir=3D"ltr">If I understand clearly, postgresql is used as a Data server=
 for the backend, and so the Android app does not connect directly to postg=
resql.<br>
The first idea is a problem on closing or recycling the connection by the b=
ackend after executing the request. Maybe wrong client connection pooling s=
ettings? </p>
<br><div class=3D"gmail_quote"><div dir=3D"ltr" class=3D"gmail_attr">Il ven=
 4 ott 2024, 06:29 KK CHN &lt;<a href=3D"mailto:kkchn.in@gmail.com">kkchn.i=
n@gmail.com</a>&gt; ha scritto:<br></div><blockquote class=3D"gmail_quote" =
style=3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><di=
v 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 mobile=
 tablet application, Android application to update the status of vehicles f=
leet say around 1000 numbers installed with the app on each vehicle along=
=C2=A0 with a=C2=A0 vehicle tracking=C2=A0 application server solution base=
d 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 vehi=
cle tracking=C2=A0app which updated every 30 seconds its location fitted in=
side the vehicle ( lat long coordinates) to the PostgreSQL DB through the j=
ava=C2=A0 backend application to know the latest location of the vehicle an=
d 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>
</blockquote></div>

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