| From: | Simon Riggs <simon(at)2ndquadrant(dot)com> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | ITAGAKI Takahiro <itagaki(dot)takahiro(at)oss(dot)ntt(dot)co(dot)jp>, pgsql-patches(at)postgresql(dot)org |
| Subject: | Re: 'Index Full Scan' for Index Scan without Index Cond |
| Date: | 2006-06-06 15:03:44 |
| Message-ID: | 1149606224.2621.515.camel@localhost.localdomain |
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| Lists: | pgsql-patches |
On Tue, 2006-06-06 at 10:31 -0400, Tom Lane wrote:
> Simon Riggs <simon(at)2ndquadrant(dot)com> writes:
> > Perhaps we should call it 'Ordered Scan' so that it is completely
> > different from 'Index Scan'?
>
> It's not an either/or proposition; the planner could be using the index
> for both selectivity and ordering.
Good point, but Itagaki's aim was to look at the ordering-only
situation, which I think would benefit from separate wording.
> This discussion is also overlooking
> the possibility that a partial index is being used for its predicate
> (again, possibly in combination with explicit index quals and/or
> interest in the sort order).
Assuming its possible, of course. I wasn't able to verify that code just
by eyeballing it, so it doesn't surprise me if you say there are issues.
--
Simon Riggs
EnterpriseDB http://www.enterprisedb.com
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