[geos-devel] fastunion aggregate

[Paul Ramsey]

Go for it.
P.

strk wrote:

> 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;
> 
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      | Paul Ramsey
      | Refractions Research
      | Email: pramsey at refractions.net
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