[postgis-devel] Validity flag

Daniel Baston dbaston at gmail.com
Sat Mar 5 14:17:13 PST 2016

If I'm not mistaken, we don't have any way of knowing where to find the
data at the end without traversing the entire geometry.  If you have a
GEOMETRYCOLLECTION with many elements, it could take a lot of operations to
find where your 1 byte is located...


On Sat, Mar 5, 2016 at 4:55 AM, Sandro Santilli <strk at keybit.net> wrote:

> On Fri, Mar 04, 2016 at 10:19:22AM -0800, Paul Ramsey wrote:
> > I think the right answer is to have an "extended info" flag on the
> > main flags slot, which, if present indicates a spare 8 bytes will be
> > inserted into the header before the bounding box. This could hold less
> > commonly used flags, like the validity values (which we would have
> > room to represent as yes, no, and unknown), solidity values, and so
> > on. It will require a bit of work on the serializer/deserializer, but
> > not a lot.
> >
> > If you're OK w/ the idea, I will implement a branch of it.
> Could you argument a bit about why you think having 8 bytes at the
> beginning is to be preferred over having 1 byte at the end ?
> --strk;
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