Re: [Maposmatic-dev] maposmatic.org unreachable ?

[Maxime Petazzoni]

* Jeroen van Rijn <address@hidden> [2013-04-04 21:54:46]:

> On Thu, Apr 4, 2013 at 9:35 PM, David MENTRÉ <address@hidden>wrote:
> 
> > Hello Maxime,
> >
> > Le 04/04/2013 20:45, Maxime Petazzoni a écrit :
> >
> >  Isn't postgresql vacuum process supposed to do that? Do we need a
> >>> >cleanup process at application level?
> >>>
> >> Vacuum takes an exclusive lock on the database and takes (interestingly)
> >> longer than doing a full planet import.
> >>
> >
> > Yes, that's strange! Those database issues are out of my knowledge but I
> > nonetheless think this vacuum behaviour should not occur.
> 
> 
> At the very least I think it's an interesting test case to bring the
> Postres/PostGIS guys in on, we might have stumbled onto an edge case in
> vacuum performance.

Not really, it's just the way vacuum works, and on a database that big
it takes a very long time, which we can't afford.

> I was also thinking along these lines. If the growth is because of the lack
> of vacuuming and the vacuuming takes this long because it's never been done
> after the initial import (I know full import disables it), it may very well
> be that suspending renders and minutely updates every hour and triggering a
> vacuum, it'll bring the database size down in minutes flat.

The main issue is that we do have vacuum turned off otherwise upgrades
were too slow. Now that we have SSDs though, I can try turning it back
on after the full import and see if that helps.

I've started a new import today, I'll let you know how it goes.

/Max
-- 
Maxime Petazzoni <http://www.bulix.org>
 ``One by one, the penguins took away my sanity.''
Writing software in California

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