| From: | Bruno Wolff III <bruno(at)wolff(dot)to> |
|---|---|
| To: | "Jim C(dot) Nasby" <jim(at)nasby(dot)net> |
| Cc: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, pgsql-general(at)postgresql(dot)org |
| Subject: | Re: Analyze not doing anything? |
| Date: | 2004-02-10 13:06:10 |
| Message-ID: | 20040210130610.GA24722@wolff.to |
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| Lists: | pgsql-general |
On Mon, Feb 09, 2004 at 18:39:48 -0600,
"Jim C. Nasby" <jim(at)nasby(dot)net> wrote:
> Hrm, I didn't realize that. Is it in the docs anywhere? I didn't see it
> in Chapter 11... I'm particularly interested in why NULL/NOT NULL isn't
> indexable.
>
> Are where clauses on indexes like
>
> email_contrib__team_id btree (team_id) WHERE (team_id IS NOT NULL)
>
> still valid/usefull? If I wanted to create the converse of that index,
While IS NULL and IS NOT NULL are not indexable, they can be used as
restrictions for partial indexes. If the matching clause is used in
a where clause, then the partial index could potentially be used
for executing the query.
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