[geos-devel] fastunion aggregate

[strk]

pramsey wrote:
> strk wrote:
> 
> > If 'fastunion' is a good name for you I'll commit, so we can test
> > togheter. 
> 
> Lets think about this. If the fastunion in fact takes up no more space 
> than the regular union, then perhaps we can simply use it with the name 
> as the geomunion(A,B)?
> 
> Then we have:
> 
> geomunion(A,B)
> geomunion(recordset)
> memgeomunion(recordset) for the future slow'n'steady version?

I can do the following:
	- commit changes to geomUnion() for soon-memory-release
	- commit support routines for "fast" union
	- post on the mailing list SQL query to enable/disable "fast" union
In this way we can test both of them on different dataset.

Fundamentally the point is the the "WORST" case memory occupation
will be about the same, while the "BEST" case memory occupation
will be MUCH less with the old code.

Imagine 3000 square polygons whose union makes a rectangle :)
Old way will take up  (releasing memory soon) a rectangle size memory.
New way will take up 3000 * square size memory (before staring to release it)

What do you think ?

--strk;