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

From Sawada Masahiko
Subject Re: Freeze avoidance of very large table.
Date
Msg-id CAD21AoDi8ws01hTP4Bn9ohF5__ej5T11RHx6G-Hmy9mZY_Jf5w@mail.gmail.com
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In response to Re: Freeze avoidance of very large table.  (Andres Freund <andres@anarazel.de>)
Responses Re: Freeze avoidance of very large table.
List pgsql-hackers
On Wed, Apr 22, 2015 at 12:02 AM, Andres Freund <andres@anarazel.de> wrote:
> On 2015-04-21 23:59:45 +0900, Sawada Masahiko wrote:
>> The page as frozen could have the dead tuple for now, but I think to change
>> to that the frozen page guarantees that page is all frozen *and* all
>> visible.
>
> It shouldn't. That'd potentially cause corruption after a wraparound. A
> tuple's visibility might change due to that.

The page as frozen could have some dead tuples, right?
I think we should to clear a bit of FrozenMap (and flag of page
header) on delete operation, and a bit is set only by vacuum.
So accordingly, the page as frozen guarantees that all frozen and all visible?

Regards,

-------
Sawada Masahiko



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