[postgis-devel] temporal indexing
Chris Hodgson
chodgson at refractions.net
Thu Aug 9 08:57:20 PDT 2007
You need to get the float minx,maxx, miny, maxy values out of the
geometry's bbox and put them into the cube constuctor. Then convert your
datetime value into a unix-timestamp format (ie. number of seconds since
the epoch date) and use that as the third value of the cube, both as the
min and the max (unless of your you have both start and end date values).
Also, note that there is a trick or two to get the functional indexing
to work. This is because cube constructor or one of the functions it
calls is not marked as "non-volatile" and postgres doesn't allow you to
index a volatile function's result.
Chris
Elena Camossi wrote:
> Hi Paul,
>
> does the cube constructor syntax allow to build a cube on geometric and
> temporal columns?
> I'm asking because all what I have found in the manual is the
> possibility to construct cube on float values.
>
> Best regards,
> -Elena
>
> On 8/8/07, *Paul Ramsey* <pramsey at refractions.net
> <mailto:pramsey at refractions.net>> wrote:
>
> I have had good success building a functional index on the cube
> constructors. That way you can have the cube index while not carrying
> the extra weight of a cube object in every tuple.
>
> Chris Hodgson wrote:
> > In order to build the cube index you will need to add an additional
> > column of type 'cube'
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>
> --
>
> Paul Ramsey
> Refractions Research
> http://www.refractions.net
> pramsey at refractions.net <mailto:pramsey at refractions.net>
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