pg_statsinfo.pid was not removed on PostgreSQL stop using systemctl

[Tomoaki Sato]

Hi,
When I stopped PostgreSQL using systemctl, pg_statsinfo.pid was not removed. You can reproduce it as follows:

# yum -y install pg_statsinfo-12.0-1.pg12.rhel7.x86_64.rpm
# su - postgres
$ /usr/pgsql-12/bin/initdb -E UTF8 --no-locale
$ cat >> $PGDATA/postgresql.conf <<EOF
shared_preload_libraries = 'pg_statsinfo'
log_filename = 'postgresql-%Y-%m-%d_%H%M%S.log'
EOF
$ exit
# systemctl start postgresql-12
# ls /var/lib/pgsql/12/data | grep .pid
pg_statsinfo.pid
postmaster.pid
# systemctl stop postgresql-12
# ls /var/lib/pgsql/12/data | grep .pid
pg_statsinfo.pid

As above, postmaster.pid has been removed, but pg_statsinfo.pid has not. When I stopped PostgreSQL using pg_ctl, pg_statsinfo.pid was removed as follows:

# su - postgres
$ /usr/pgsql-12/bin/pg_ctl start
$ ls $PGDATA | grep .pid
pg_statsinfo.pid
postmaster.pid
$ /usr/pgsql-12/bin/pg_ctl stop
$ ls $PGDATA | grep .pid

Is it a bug in pg_statsinfo?

Best regards,
Tomoaki Sato