Tom Lane [mailto:tgl@sss.pgh.pa.us] Wrote:

> There's no HOWTO for rtree either. Again, my point is not
> that one couldn't be written; it's that we would probably be
> better off spending the effort on a HOWTO for gist.

No, but the _current_ implementation of the rtree operators are ver much
self explaining and need no howto.

Union(x,y) = x + y
Intersect(x,y) = the values that are present in both x and y, or
_overlapping_region_
Size(x) = the size of the area/length of the line, number of elements,
etc...

Now, how simple is that compared to gist?

I for one, is yet to produce a working example of something as simple as
indexing an array of 2 elements [x y] represented by a custom type as
'[x y]' in string format (returned by type_out) internally stored as a
char[2], so that I can fetch all rows where [x y] = ':y' (:y meaning 2nd
element in array, x: meaning first element in array.

I chose this as something simple to play with, having no practical
application for me, but to get an understanding of gist,.... For now,. I
have put it in the too hard basket.

I did however in about half a day implement rtree support for inet/cidr
(ipv4 only) as you might recall.

Kind Regards,

John


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"John Hansen" <john@geeknet.com.au> writes:
> No, but the _current_ implementation of the rtree operators are ver much
> self explaining and need no howto.

That reasoning no doubt explains why we don't have *any* rtree-like
opclasses that got the left/overleft/right/overright semantics right
the first time :-(.

Greg Stark is right that the GIST API could probably be simpler ---
in particular it would be interesting to see if we could offer a
default picksplit function that most opclasses could use. But that
doesn't mean that the rtree API is exactly trivial.

regards, tom lane

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