[pdal] pgpointcloud selector filter and max_capacity

[Howard Butler]

> On Feb 4, 2015, at 3:37 AM, Oscar Martinez Rubi <O.MartinezRubi at tudelft.nl> wrote:
> 
> 2 - There seems to be a hardcoded maximum of 400 points per patch in the pgpointcloud writer. I know that is the recommended patch size but for massive point clouds I use larger number which use to be possible with older PDALs but not anymore.

> About the capacity I found out that i need to specify the capacity in both writter and chipper.

Because of the way PDAL used to work, you needed to specify the patch size on both the writer and the filters.chipper. That doesn't have to be the case anymore (but still is). The issue that's left is how to communicate the filter's capacity down to the pgpointcloud writer...

I would note that during my tests, there was a huge performance penalty for patches greater than a database page size due to the way that toast works [1]. With compression turned on, this will allow you to have more points per patch, but I think you still want their total storage to be less than the page size if you can help it.

Howard


[1] http://www.postgresql.org/docs/9.4/static/storage-toast.html