[pgpointcloud] RLE and SIGBITS heuristics

[Sandro Santilli]

On Wed, Apr 15, 2015 at 08:31:45PM +0200, Rémi Cura wrote:
> From what I understand pgpointcloud is much faster to uncompress zip than
> to compress it.
> (roughly about 3 times)

That's supposedly the norm with deflate compression, to be faster
at decompressing (and probably true for most other compression schemes).

How do you test decompression speed ?

I found my initial naive attempt of using PC_FilterEquals to be misleading
as the result of PC_FilterEquals is again a patch, and the patch is
compressed again using the schema-determined compression.

This means that PC_FilterEquals( PC_Uncompress(p), ... ) returns a
_compressed_ patch, incurring in both decompression and compression
costs.

I'm not sure this is a sane behavior.

--strk;