On Mon, Oct 7, 2024 at 12:07 AM Alvaro Herrera <alvherre@xxxxxxxxxxxxxx> wrote:
On 2024-Oct-04, KK CHN wrote:
> 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).
It sounds like setting TCP keepalives in the connections between the
Wildfly and the vehicles might help get the number of dead connections
down to a reasonable level. Then it's up to Wildfly to close the
connections to Postgres in a timely fashion. (It's not clear from your
description how do vehicle connections to Wildfly relate to Postgres
connections.)
Where do I have to introduce the TCP keepalives ? in the OS level or application code level ?
[root@dbch wildfly-27.0.0.Final]# cat /proc/sys/net/ipv4/tcp_keepalive_time
7200
[root@dbch wildfly-27.0.0.Final]# cat /proc/sys/net/ipv4/tcp_keepalive_intvl
75
[root@dbch wildfly-27.0.0.Final]# cat /proc/sys/net/ipv4/tcp_keepalive_probes
9
[root@dbch wildfly-27.0.0.Final]#
7200
[root@dbch wildfly-27.0.0.Final]# cat /proc/sys/net/ipv4/tcp_keepalive_intvl
75
[root@dbch wildfly-27.0.0.Final]# cat /proc/sys/net/ipv4/tcp_keepalive_probes
9
[root@dbch wildfly-27.0.0.Final]#
These are the default values in the OS level. Do I need to reduce all the above three values to say 600, 20, 5 ? Or need to be handled in the application backend code ?
Any hints much appreciated..
I wonder if the connections from Wildfly to Postgres use SSL? Because
there are reported cases where TCP connections are kept and accumulate,
causing problems -- but apparently SSL is a necessary piece for that to
happen.
No SSL in between Wildfly (8080 ) to PGSQL(5432). Both the machines internal lan VMs in the same network. Only the devices on the field (fitted on the vehicles) communicate to the application backend via a public URL :443 port then it connectes to the 8080 of wildfly then the java code connects the database server running on 5432 on the internal LAN network.
--
Álvaro Herrera 48°01'N 7°57'E — https://www.EnterpriseDB.com/
Thou shalt study thy libraries and strive not to reinvent them without
cause, that thy code may be short and readable and thy days pleasant
and productive. (7th Commandment for C Programmers)
