| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Christopher Kings-Lynne <chriskl(at)familyhealth(dot)com(dot)au> |
| Cc: | Hannu Krosing <hannu(at)skype(dot)net>, Hackers <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Order by optimisations? |
| Date: | 2005-07-15 04:59:44 |
| Message-ID: | 7590.1121403584@sss.pgh.pa.us |
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| Lists: | pgsql-hackers |
Christopher Kings-Lynne <chriskl(at)familyhealth(dot)com(dot)au> writes:
> OK, so what's going on here?
> usa=> explain select * from users_myfoods_map where user_id=1 and
> date='2003-11-03' order by date;
> QUERY PLAN
> -------------------------------------------------------------------------------------------------------------------
> Sort (cost=4.84..4.85 rows=2 width=22)
> Sort Key: date
> -> Index Scan using users_myfoods_map_user_id_date_key on
> users_myfoods_map (cost=0.00..4.83 rows=2 width=22)
> Index Cond: ((user_id = 1) AND (date = '2003-11-03'::date))
> (4 rows)
Well, date evidently isn't the high-order key of this index. But why
exactly are you worried about a sort of 2 rows?
regards, tom lane
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