Re: Idea for getting rid of VACUUM FREEZE on cold pages

On Thu, May 27, 2010 at 3:15 PM, Kevin Grittner
<Kevin.Grittner@wicourts.gov> wrote:
> Jesper Krogh <jesper@krogh.cc> wrote:
>
>> Couldn't pages that are totally filled by the same transaction, be
>
>> frozen on the initial write?
>
> As far as I'm aware, that can only be done if:
>
> (a)  The tuples were written within the same transaction which
> created or truncated the table.
>
> *or*
>
> (b)  The writing transaction and all transactions concurrent to it
> have completed by the time the page is about to be written.

Actually, I think this is true only in case (b).  In case (a), you
mess up visibility with respect to other command-IDs within the
transaction.

--
Robert Haas
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