| From: | "Bramandia Ramadhana" <bramandia(at)gmail(dot)com> |
|---|---|
| To: | "Gregory Stark" <stark(at)enterprisedb(dot)com> |
| Cc: | "Heikki Linnakangas" <heikki(dot)linnakangas(at)enterprisedb(dot)com>, pgsql-hackers(at)postgresql(dot)org |
| Subject: | Re: Block nested loop join |
| Date: | 2008-10-10 08:45:30 |
| Message-ID: | 700260640810100145k14610225k36e668be18ea6225@mail.gmail.com |
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| Thread: | |
| Lists: | pgsql-hackers |
Thanks for the clarifications.
Just for curiosity, is there any reason of not having block nested-loop join
implementation? Is it rarely useful?
As far as I am aware of, in the case of cross product of two tables, block
nested-loop join is the most efficient algorithm.
Regards,
Bramandia R.
On Fri, Oct 10, 2008 at 3:30 PM, Gregory Stark <stark(at)enterprisedb(dot)com>wrote:
>
> Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com> writes:
>
> >> Does postgresql support block nested loop join?
> >
> > Nope.
>
> We do support Hash Join though so I think the only difference is that we
> can't
> use the hash join for cartesian joins.
>
> --
> Gregory Stark
> EnterpriseDB http://www.enterprisedb.com
> Ask me about EnterpriseDB's PostGIS support!
>
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