Re: Freeze avoidance of very large table.

On Tue, Feb 2, 2016 at 11:42 AM, Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com> wrote:
> 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.

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