| From: | Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com> |
|---|---|
| To: | Pavan Deolasee <pavan(dot)deolasee(at)gmail(dot)com> |
| Cc: | pgsql-hackers <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: visibility maps and heap_prune |
| Date: | 2008-12-06 14:38:02 |
| Message-ID: | [email protected] |
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| Thread: | |
| Lists: | pgsql-hackers |
Pavan Deolasee wrote:
> ISTM that the PD_ALL_VISIBLE flag and the visibility map bit can be set at
> the end of pruning operation if we know that there are only tuples visible
> to all transactions left in the page.
Right.
> The way pruning is done, I think it
> would be straight forward to get this information.
Is it? I thought about that a bit while writing the patch, but didn't
see any obvious way to do it. Except by adding a loop through all tuples
on the page, but that's extra overhead. I think we're looping through
all tuples in the pruning, but it's not quite obvious.
If you see a straightforward way, please submit a patch!
--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com
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