Re: Freeze avoidance of very large table. - Mailing list pgsql-hackers

From Masahiko Sawada
Subject Re: Freeze avoidance of very large table.
Date
Msg-id CAD21AoDB-J1b=fs63HFu7hMJ7zoH-B5W7RgqT=7Eds7uObqz0A@mail.gmail.com
Whole thread Raw
In response to Re: Freeze avoidance of very large table.  (Masahiko Sawada <sawada.mshk@gmail.com>)
Responses Re: Freeze avoidance of very large table.
List pgsql-hackers
On Tue, Feb 2, 2016 at 11:42 AM, Masahiko Sawada <sawada.mshk@gmail.com> wrote:
> On Tue, Feb 2, 2016 at 10:15 AM, Jim Nasby <Jim.Nasby@bluetreble.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.

I misunderstood. Sorry for noise.
I agree with adding conversion method as a pageConverter routine.

This patch doesn't change page layout actually, but pageConverter
routine checks only the page layout.
And we have to plugin named convertLayout_X_to_Y.

I think we have two options.

1. Change page layout(PG_PAGE_LAYOUT_VERSION) to 5. pg_upgrade detects
it and then converts only VM files.
2. Change pg_upgrade plugin mechanism so that it can handle other name
conversion plugins (e.g., convertLayout_vm_to_vfm)

I think #2 is better. Thought?

Regards,

--
Masahiko Sawada



pgsql-hackers by date:

Previous
From: Michael Paquier
Date:
Subject: Re: silent data loss with ext4 / all current versions
Next
From: Oleg Bartunov
Date:
Subject: Re: [PATCH] Phrase search ported to 9.6