Re: 9.3 feature proposal: vacuumdb -j # - Mailing list pgsql-hackers

From Andres Freund
Subject Re: 9.3 feature proposal: vacuumdb -j #
Date
Msg-id 201201171504.47925.andres@anarazel.de
Whole thread Raw
In response to Re: 9.3 feature proposal: vacuumdb -j #  (Jaime Casanova <jaime@2ndquadrant.com>)
List pgsql-hackers
On Tuesday, January 17, 2012 01:33:06 PM Jaime Casanova wrote:
> On Tue, Jan 17, 2012 at 7:23 AM, Andres Freund <andres@anarazel.de> wrote:
> > On Tuesday, January 17, 2012 01:18:53 PM Susanne Ebrecht wrote:
> >> I would prefer to have an option that the user is able to tell on how
> >> much cores it should be shared. Something like --share-cores=N.
> > 
> > Uhm. -j # does exactly that or am I missing your point?
> 
> not really.
> 
> if you have 12 cores and you say -j 12 you would have 1 process per
> core, with Susanne's suggestion, AFAIUI, you can say -j 12
> --shared-cores=6... so you would only use 6 cores of the 12 and have 2
> processes per core
I don't really get what that should do. If vacuumdb itself is a limit in any 
form in this we did something *very* wrong (in my opinion using processes for 
this is pointless anyway. Using async queries seems to be much easier for this 
special case. Especially for distributing individual commands.).
I don't really see how you could enforce sharing cores on the server side 
(well, there are cpusets, but were sure not introduce usage of that just for 
vacuumdb).

Andres


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