Re: [GSoC2014] Patch ALTER TABLE ... SET LOGGED

From: Fabrízio de Royes Mello <fabriziomello(at)gmail(dot)com>
To: Robert Haas <robertmhaas(at)gmail(dot)com>
Cc: Alvaro Herrera <alvherre(at)2ndquadrant(dot)com>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Andres Freund <andres(at)2ndquadrant(dot)com>, Heikki Linnakangas <hlinnakangas(at)vmware(dot)com>, Thom Brown <thom(at)linux(dot)com>, Christoph Berg <cb(at)df7cb(dot)de>, Pgsql Hackers <pgsql-hackers(at)postgresql(dot)org>, Stephen Frost <sfrost(at)snowman(dot)net>
Subject: Re: [GSoC2014] Patch ALTER TABLE ... SET LOGGED
Date: 2014-08-22 19:44:33
Message-ID: CAFcNs+pN8ee2E5an=kCD2M-hK1r+ix5xcpjWFJYszDepS6tR+g@mail.gmail.com
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On Fri, Aug 22, 2014 at 4:22 PM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
>
> On Fri, Aug 22, 2014 at 2:32 PM, Alvaro Herrera
> <alvherre(at)2ndquadrant(dot)com> wrote:
> > Fabrízio de Royes Mello wrote:
> >> Em sexta-feira, 22 de agosto de 2014, Alvaro Herrera <
> >> alvherre(at)2ndquadrant(dot)com> escreveu:
> >>
> >> > Fabrízio de Royes Mello wrote:
> >> >
> >> > > I forgot to mention... I did again a lot of tests using different
> >> > > replication scenarios to make sure all is ok:
> >> > > - slaves async
> >> > > - slaves sync
> >> > > - cascade slaves
> >> >
> >> > On v13 you mean?
> >> >
> >> Exactly!
> >
> > Great. Pushed. Thanks for the patch.
>
> Hmm. I confess to not having paid enough attention to this, but:
>
> 1. Loggedness is not a word. I think that "persistence" or
> "relpersistence" would be better.
>

I changed to "Persistence"...

> 2. The patch seems to think that it can sometimes be safe to change
> the relpersistence of an existing relation. Unless you can be sure
> that no buffers can possibly be present in shared_buffers and nobody
> will use an existing relcache entry to read a new one in, it's not,
> because the buffers won't have the right BM_PERSISTENT marking. I'm
> very nervous about the fact that this patch seems not to have touched
> bufmgr.c, but maybe I'm missing something.
>

Because of this concern I implement a solution pointed by Andres [1].

Regards,

[1]
http://www.postgresql.org/message-id/20140717230220.GK21370@awork2.anarazel.de

--
Fabrízio de Royes Mello
Consultoria/Coaching PostgreSQL
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>> Github: http://github.com/fabriziomello

Attachment Content-Type Size
change-loggedness-to-persistence.patch text/x-diff 4.0 KB

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