Thread: Quick pointer required re indexing geometry

Witting a box@>point function easy. Having a spot of trouble trying to
figure out where and how to graft this into the GiST stuff. Could
someone please point me in the general direction?

Thanks.

Hi,

Paul Matthews <plm@netspace.net.au> writes:
> Witting a box@>point function easy. Having a spot of trouble trying to
> figure out where and how to graft this into the GiST stuff. Could
> someone please point me in the general direction?

You want index support for it, I suppose?

Without index support (but needed anyway), you implement your code in a
C module then make it visible from SQL. I'm not sure you're asking help
for the C part so don't expand, please ask more if needed:

CREATE OR REPLACE FUNCTION box_contains_point(box, point)
RETURNS bool
AS 'MODULE_PATHNAME'
LANGUAGE 'C' IMMUTABLE STRICT;

CREATE OPERATOR @> (LEFTARG    = box,RIGHTARG   = point,PROCEDURE  = box_contains_point,COMMUTATOR = '<@',RESTRICT   =
contsel,JOIN      = contjoinsel
 
);
COMMENT ON OPERATOR @>(box, point) IS 'box contains point?';


Now for adding support for index lookups, you have to see documentation
about OPERATOR CLASS and OPERATOR FAMILY. I guess you need to make a
family out of point and box if none already exists, add the @> operator
there and point to your function.

I'm unclear if you need to add it to an OPERATOR CLASS too and which, so
I won't risk into writing the commands. Cross datatype indexing support,
as far as I've understood, is tied together with operator families.

Hope this helps, regards,
-- 
dim

Dimitri Fontaine wrote:<br /><blockquote cite="mid:87vdkuh2vk.fsf@hi-media-techno.com" type="cite"><pre wrap="">Paul
Matthews<a class="moz-txt-link-rfc2396E" href="mailto:plm@netspace.net.au"><plm@netspace.net.au></a> writes:
</pre><blockquotetype="cite"><pre wrap="">Witting a box@>point function easy. Having a spot of trouble trying to
 
figure out where and how to graft this into the GiST stuff. Could
someone please point me in the general direction?   </pre></blockquote><pre wrap="">
You want index support for it, I suppose? </pre></blockquote> Yes<br /><blockquote
cite="mid:87vdkuh2vk.fsf@hi-media-techno.com"type="cite"><pre wrap="">Without index support (but needed anyway), you
implementyour code in a
 
C module then make it visible from SQL.  ...cut... 
COMMENT ON OPERATOR @>(box, point) IS 'box contains point?'; </pre></blockquote> All done but the comment part :-)
<br/><blockquote cite="mid:87vdkuh2vk.fsf@hi-media-techno.com" type="cite"><pre wrap="">
 
Now for adding support for index lookups, you have to see documentation
about OPERATOR CLASS and OPERATOR FAMILY.
Hope this helps, regards, </pre></blockquote> Thanks overlooked CLASS and FAMILY in my hurry. Hopefully that is where
theproblem is.<br /><br /> What I am hoping to do is provide a "real" patch to make box@>point available for all.
Butwe can get to that later. A lot of code in pgsql, but not much in the way of comments.<br />