Re: Server instrumentation for 8.1 - Mailing list pgsql-hackers

From Magnus Hagander
Subject Re: Server instrumentation for 8.1
Date
Msg-id 6BCB9D8A16AC4241919521715F4D8BCE6C748F@algol.sollentuna.se
Whole thread Raw
In response to Server instrumentation for 8.1  (Andreas Pflug <pgadmin@pse-consulting.de>)
Responses Re: Server instrumentation for 8.1  (Andreas Pflug <pgadmin@pse-consulting.de>)
Re: Server instrumentation for 8.1  (Alvaro Herrera <alvherre@surnet.cl>)
List pgsql-hackers
> >>- There was a pg_kill_backend function in pre-8.0, but it
> was dropped
> >>because "it's too dangerous". Incidentially, I've been in
> the situation
> >>more than once where I needed to kill a backend process
> that was running
> >>wild; alternatively, I'd have to shutdown the whole server.
> I had to do
> >>this on the linux console with kill -9 (fortunately I did
> have access),
> >>or using the win32 task manager (same). This appears even more error
> >>prone to me than to point to the malicious process and kill
> it (through
> >>pgadmin/pg_kill_backend)
> >
> >
> > Certainly.  But this was dropped because Tom couldn't get
> the bugs out (as I
> > recall) and make it "safe" to use, even for the superuser.
>
> Hm, don't remember that, AFAIR it was removed after a
> discussion between
> Tom and Dave that kill -9 would stress a code path that still isn't
> elaborated too much. But in the situations mentioned above, I
> took the
> risk and would like a function for that.

Not kill -9. Kill -9 is "safe" because it causes a complete restart of
the postmaster (it's the same as a backend crash, really). Kill -INT is
also safe, because it does a simlpe query cancel.

kill -TERM is the unsafe one. It is also the one most people use.

//Magnus


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