intermittent issue with windows 7 service manager not able to correctly determine or control postgresql 9.4

Hi All,

I've got several machines running windows 7 which have postgresql 9.4 installed as a service, and configured to start automatically on boot. I am monitoring these services with zabbix and several times a week I get a notification that the postgresql-x64-9.4 service has stopped.

When I login to the machine, the service does appear to be stopped;


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However when I check the database, I can query it ok;

C:\Program Files\PostgreSQL\9.4>bin\psql.exe -U postgres -c "SELECT count(*) from media;" association
Password for user postgres:
  count
---------
 1167846
(1 row)

If I try to start the service from the service manager, I see the following error in the logs;

2016-04-30 05:03:13 BST FATAL:  lock file "postmaster.pid" already exists
2016-04-30 05:03:13 BST HINT:  Is another postmaster (PID 2556) running in data directory "C:/Program Files/PostgreSQL/9.4/data"?

The pg_ctl tool seems to correctly query the state of the service and return the correct PID;

C:\Program Files\PostgreSQL\9.4>bin\pg_ctl.exe -D "C:\Program Files\PostgreSQL\9.4\data" status
pg_ctl: server is running (PID: 2556)

The other thing that seems to happen is the pgadmin3 tool seems to have lost the ability to control the service as all the options for start/stop are greyed out;

The only option to get the control back is to kill the processes in the task manager or reboot the machine.

Any suggestions on what might be causing this?

Thanks,

Tom