| From: | Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com> |
|---|---|
| To: | Jim Nasby <Jim(dot)Nasby(at)bluetreble(dot)com> |
| Cc: | Alvaro Herrera <alvherre(at)2ndquadrant(dot)com>, Robert Haas <robertmhaas(at)gmail(dot)com>, Kyotaro HORIGUCHI <horiguchi(dot)kyotaro(at)lab(dot)ntt(dot)co(dot)jp>, Michael Paquier <michael(dot)paquier(at)gmail(dot)com>, Bruce Momjian <bruce(at)momjian(dot)us>, Jeff Janes <jeff(dot)janes(at)gmail(dot)com>, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>, Andres Freund <andres(at)anarazel(dot)de>, Simon Riggs <simon(at)2ndquadrant(dot)com>, Josh Berkus <josh(at)agliodbs(dot)com>, Masao Fujii <masao(dot)fujii(at)gmail(dot)com>, Petr Jelinek <petr(at)2ndquadrant(dot)com>, Greg S <stark(at)mit(dot)edu>, "pgsql-hackers(at)postgresql(dot)org" <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Freeze avoidance of very large table. |
| Date: | 2016-02-02 02:42:16 |
| Message-ID: | CAD21AoDQJ455FdkVJbskxkUNsemQzS3bq-jw+Ahw5UJKma4NCw@mail.gmail.com |
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| Lists: | pgsql-hackers |
On Tue, Feb 2, 2016 at 10:15 AM, Jim Nasby <Jim(dot)Nasby(at)bluetreble(dot)com> wrote:
> On 2/1/16 4:59 PM, Alvaro Herrera wrote:
>>
>> Masahiko Sawada wrote:
>>
>>> Attached updated version patch.
>>> Please review it.
>>
>>
>> In pg_upgrade, the "page convert" functionality is there to abstract
>> rewrites of pages being copied; your patch is circumventing it and
>> AFAICS it makes the interface more complicated for no good reason. I
>> think the real way to do that is to write your rewriteVisibilityMap as a
>> pageConverter routine. That should reduce some duplication there.
>
This means that user always have to set pageConverter plug-in when upgrading?
I was thinking that this conversion is required for all user who wants
to upgrade to 9.6, so we should support it in core, not as a plug-in.
>
> IIRC this is about the third problem that's been found with pg_upgrade in
> this patch. That concerns me given the potential for disaster if freeze bits
> are set incorrectly.
Yeah, I tend to have diagnostic tool for visibilitymap, and to exactly
compare VM between old one and new one after upgrading postgres
server.
I've implemented a such tool that is in my github repository[1].
I'm thinking to add this tool into core(e.g., pg_upgrade directory,
not contrib module) as testing function.
[1] https://github.com/MasahikoSawada/pg_visibilitymap
Regards,
--
Masahiko Sawada
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