| From: | Heikki Linnakangas <heikki(at)enterprisedb(dot)com> |
|---|---|
| To: | Martijn van Oosterhout <kleptog(at)svana(dot)org> |
| Cc: | ITAGAKI Takahiro <itagaki(dot)takahiro(at)oss(dot)ntt(dot)co(dot)jp>, "Jim C(dot) Nasby" <jim(at)nasby(dot)net>, pgsql-hackers(at)postgresql(dot)org |
| Subject: | Re: Another idea for dealing with cmin/cmax |
| Date: | 2006-09-29 09:59:13 |
| Message-ID: | 451CEE71.40600@enterprisedb.com |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
Martijn van Oosterhout wrote:
> On Fri, Sep 29, 2006 at 09:35:31AM +0100, Heikki Linnakangas wrote:
>> We could get rid of t_hoff, because we should always be able to
>> calculate the header size. Then we're down to 18 bytes.
>
> Without t_hoff, how do you know the size of the null bitmap? You could
> probably do it only if you assume the null bitmap, if present, always
> covers all the columns...
I think we assume that already. heap_form_tuple reserves space for the
bitmap like this:
if (hasnull)
len += BITMAPLEN(numberOfAttributes);
--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Martijn van Oosterhout | 2006-09-29 10:05:15 | Re: Another idea for dealing with cmin/cmax |
| Previous Message | Martijn van Oosterhout | 2006-09-29 09:52:59 | Re: Another idea for dealing with cmin/cmax |