Re: how to terminate a process when kill fails

Johnson, Shaunn wrote:
>
> Running PostgreSQL 7.2.1 on RedHat Linux 7.2.
>
> I think I may have asked before, but I never got an answer
> that told me one way or another -
>
> How can I kill processes without kill -9 <pid> and
> ruining the database?
>
> I've tried restarting postgreSQL hoping that it cleans up
> a few things. I've tried to simply kill the processes that
> were running. Nothing happens; nothing dies. I don't see
> much of anything in the messages / log files.
>
> Any suggestions?

Use kill -9. Do a:

killall -9 postgres
killall -9 postmaster

The tip message

'Don't kill -9 the postmaster'

is old and was added when havoc could be caused by an old
postgres backend process. Consider the scenrio:

1. postmaster started
2. postgres started (Session #1)
3. postmaster killed (-9)
4. postmaster restarted
5. postgres started (Session #2)

Now there isn't any synchronization between Sesison #1 and
Session #2 at all, which would lead to data corruption. This
scenario was fixed a long time ago (7.1?). The whole 'Don't kill
-9 the postmaster' comment was actually a tongue-in-cheek remark
by me regarding a parallel discussion of RedHat init scripts.
The corruption possibility has long-since been fixed. Since I've
seen FUD claiming PostgreSQL doesn't have sufficient
crash-recovery because of the tip, I suggest the tip be changed to:

'Feel free to kill -9 the postmaster'

Mike Mascari
mascarm(at)mascari(dot)com