How to produce: - Simple install pgsql 11 on CentOS from yum repo of postgresql.org - init the cluster - start the server - wait some time
The query you show is not executed merely due to the passage of time. Something is executing that query. It is probably a monitoring tool.
Since procpid was removed back in version 9.2, the monitoring tools seems massively out of date. It is possible this tool has buggy code to detect the version, and concludes that v11 is prior to 9.2. But that seems unlikely to be broken by v11 but not by v10. Do you have the same problem in v10?
Figure out what your monitoring tool is and report the bug to its maintainer.
