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Re: Questions about GIS functionality (vs MySQL, InnoDB, PostGIS...)


06.08.2012 15:32, Henrik Ingo wrote:
On Mon, Aug 6, 2012 at 2:14 PM, Alexey Botchkov <holyfoot@xxxxxxxxxxxx> wrote:
It seems MySQL 5.6.1 also supports accurate arithmetic now, not just the old bounding box arithmetic. Ie ST_*() functions. http://dev.mysql.com/doc/refman/5.6/en/functions-for-testing-spatial-relations-between-geometric-objects.html#functions-that-test-spatial-relationships-between-geometries

They do have the exact spatial functions.
I meant not all of them work properly. Particularly cases when nodes or edges of different shapes coincide
can produce inpredictable results.

Right. But even if you do it in 2 steps, it's still transparent to the
user. Apparently in PostGIS, unless you use a rectangle for searching,
it won't use the index at all. So you have to explicitly supply first
a rectangle, then AND combine it with the shape you really want.
(Which works, you can easily get the MBR for your shape, but very
annoying to have to do it explicitly.)

We suppose the query optimizer should do that, so you just specify your complicated
shape and Maria takes the MBR internally for the index.
The 'spatial' optimizer isn't too smart yet, still can handle simple ST_Intersection() queries.

Ah, that's good news. When that is done, the only complaint really
would be no support for InnoDB. Which one can live with but still
worth mentioning as most MySQL usage is InnoDB-only nowadays.


Best regards.