Re: crash-safe visibility map, take three

Heikki Linnakangas <heikki.linnakangas@enterprisedb.com> writes:
> On 30.11.2010 19:22, Tom Lane wrote:
>> But having said that, I wonder whether we need a full-page image for
>> a WAL-logged action that is known to involve only setting a single bit
>> and updating LSN.

> You have to write a full-page image if you update the LSN, because 
> otherwise the next update that comes along will not write a full page image.

Um.  Drat.  I was thinking about the replay side, where I think it would
actually work --- but you're right, it would break the logic on the
generation side.  Unless you want to put in some kind of flag saying
"this was only a visibility bit update, any bigger update still needs
to write an FPI".
        regards, tom lane