Re: canceling query - Mailing list pgsql-hackers-win32

From Magnus Hagander
Subject Re: canceling query
Date
Msg-id 6BCB9D8A16AC4241919521715F4D8BCE34B7A0@algol.sollentuna.se
Whole thread Raw
In response to canceling query  ("Merlin Moncure" <merlin.moncure@rcsonline.com>)
List pgsql-hackers-win32
> > It should die once it tries to send data down the TCP connection,
> > though. Since the other end of the socket is gone. Do you
> know if your
> > query gets that for, or is it still executing?
>
> Still executing.  CPU load high, and pg_stat_activity reports
> that particular query running on that particular backend.

Ok. If you have the time/CPU to spare, it would be intersting to see if
it goes down once it starts sending results to the frontend (which is
gone).


> > There really should be no need to bring down the entire postmaster.
>
> Yes...Isn't it possible to set up your app so that it can't
> be brought down by the task manager?  (IIRC this may only be
> possible with
> services)  Of course, this is not a good idea until there is
> a proper cancel.

No, this can't be done.
A GUI program can be set to ignore close requests, but you cannot
prevent it from being killed from the "processes" tab. Unless you put in
a kernel driver there to prevent it, and that's not going to happen :-


> My personal design philosophy is to try and keep normal query
> execution time < 1 sec, so I'm not overly concerned about
> this.  I'm just beating on the postmaster to see what can
> come up with.

Oh yes, this kind of testing is defintly what we need now.

//Magnus

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