Re: CLOSE_WAIT pileup and Application Timeout

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(dot)in(at)gmail(dot)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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