Re: VACUUM always makes all pages dirty

On 10/24/07, Heikki Linnakangas <heikki(at)enterprisedb(dot)com> wrote:
>
>
> Yeah, it's definitely a HOT-introdued thing. Vacuum calls
> heap_page_prune on every page, and this in heap_page_prune is dirtying
> the buffer:
>
> > else
> > {
> > /*
> > * If we didn't prune anything, we have nonetheless
> updated the
> > * pd_prune_xid field; treat this as a non-WAL-logged
> hint.
> > */
> > SetBufferCommitInfoNeedsSave(buffer);
> > }
>
> I don't have time to dig deeper at this moment. I'll take a look later
> today, unless someone beats me to it. We obviously don't want to call
> SetBufferCommitInfoNeedsSave if we didn't really change the pd_prune_xid
> field.
>
>
I am looking at it. We must not call SetBufferCommitInfoNeedsSave unless
we make any state changes to the page.

Thanks,
Pavan

--
Pavan Deolasee
EnterpriseDB http://www.enterprisedb.com